Hey,
We receive very informed “Your Shot” responses from knowledgeable builders all over the world. It dawned on me one day to gather the good ones and archive them as if they were jewels discovered on a beach. Actually, for a rider who’s broke down they’re worth more than diamonds.
I’m going to save hot, informative “Your Shot” letters daily and post them here under various categories. We’ll do our best to file these is a way that’s most useful. I’ll create categories and alphabetize them for easy find. As this grows, we may come up with more user-friendly technically wise ways to post them, but until them, here goes.
Wait just a minute. Like most areas on Bikernet, there will be some fun added from time to time. I’m not tellin’ what time… Just hang on:
The 32-amp system is stock on all '89 and later carbureted 1340 models. The 32-amp system fits all '84-88 FLT, FLHT, AND FXR (wet clutch models. It will not fit '84-'88 Softails.
The 22-amp kit fits '82 and earlier 1200/1340 FL, FX, and FLT. Came stock on '83-'88 models.
You're right. You can't mix up the leads to the regulator. Just make sure not to use the hot wire that goes to the battery or the ground strap.
LONG STORY…
Brother died, friend inherited scooter, friend could never part with scooter, but friend is clueless when it comes to maintenance. Bike won't run, friend brings bike to me, please make bike run as best as can, thanks, ok.
Motor is relatively fresh. Been converted to 12 electrics, a whole 5.5 amp battery, probably very dead. Someone rigged a 40 mil CV Keihin on there, but the intake doesn't look like it seals very well, bike has been totally rigged by previous owner. But as I remember, this bike ran like a bastard for the old fucker. Course, it was his bike, and he knew every nut and bolt.
I need to make it a little more user freindly, just enough so that it will start, after sitting for a while, run for a few miles, and start again. What are the first things one would do to a Pan to make it run a little more reliably?
It's got new points and condenser, gap is good, plugs are new, etc., plus the basic 12 volt conversion is done. I'm perfectly willing to spend some money to get this thing running well, but I don't want to throw money away. What's the best carb? I've got some butterfly Keihins laying around……..
What kind of upgrades are available for the charging system? It's kick only, of course. What's the best battery that can fit in a 5 1/4″ long, by 6 1/2″ high, by 3-4inch wide horseshoe tank? Got a Yuasa 12N12A-4A-1 in there now. Any help appreciated. Dutch.–Dutch
BRAKE LIGHT BLUES
Ok, you replaced the switches but nothing changed. Don't worry about the anti dive shit or the calipers they are only symptoms of the problem not the cause. Troubleshooting is an art. But it's just a matter of understanding the problem and finding the cause. First off you should have a manual for your bike. If you don't STOP RIGHT HERE AND GO GET ONE! We'll wait for you to get back.
Now that you have a manual, you can follow the wires to the brake switch (either one) and from there to “wherever it goes”. Now that is probably to a little black box that controls the actual lights, and hopefully the anti dive dew-hicky. There is an old saying in the electronics world, “garbage in, garbage out”. This adapts nicely to a lot of problems.
If you have a volt meter get it, if not go down to the auto parts store and get one of the those little “continuity checkers”. It's a light bulb. Find out if you are getting 12V into the black box when you apply the brakes (yes, key on). Check the connectors while you are there. If you are not blowing fuses I wouldn't spend a bunch of time doing it, but look for damaged wires. Wherever they bend or move, like at the neck, you could have a broken or damaged wire. They do get pinched.
My ‘98 Sporty developed a problem right off the bat when the wires they hide under the headlight cowl rubbed thru the insulation…Anyway if you have a good signal into the box and the fuckers don't light it could be bad. Notice, I said, “could.” Look at the wiring diagram again. Does anything else tie into the wire before it gets to the blinker module (the black box)? That's how I would go about it after I eliminate loose connections or bad wires. Believe me, when I tell you, after 26 years of doing component level troubleshooting, I have never seen a part fix itself.
Electronic components are never intermittent unless they have a mechanical portion. And then that’s the problem. If you EVER have an electrical problem that comes and goes do not waste money changing electric parts. Find the bad connection, period. Now that I have made a generality, yes I know there is always at least one exception.
TACH HOOK-UP
Ok here we go…Night train into Fat boy, the tubes for the fatboy are 2 inches under what the Night train uses, you have to compensate for that with new longer tubes……. Tach, if it's an electronic tachometer it will work on the bike, the cables from the ignition provide one for the tach (depending on the ignition) some H-D models have a plug so all you do is match female-male……
Don't matter how you connect to it, a coil fires with the same signal. You should be able to hook up a tach for Harley's. I wouldn't think of cutting up the connector at the coil though. Just follow the wire, you did get a manual with wiring diagrams right, and find a nice spot to splice it. Use a fucking soldering iron and some heat shrink. Put a little RTV on the solder joint before you shrink the tubing over it to seal it from the weather.
But before you do ANYTHING look at the wiring diagram in the manual. It probably already has a dedicated wire in the wiring bundle for a tach. After all H-D wants you to add one, one of theirs. The wire is probably there and just needs to be pulled loose so you can connect to it.
If you use crimp splices and get stranded don't blame me.
BLINKER BLUES
If the new blinkers are LED and you didn't change anything else the H-D blinker module is the problem. It needs lots of current to work right. The stock bulbs draw AMPS of current, the LED's only milliamps. Almost certainly 1/10 or less of what the HD blinker module needs.
Don't go get a “load equalizer”, it's just a plastic box with some resistor in it to throw away a bunch of current as heat. That of course causes them to burn up a lot. Get a new blinker module to replace the factory unit. There are MANY on the market. Most allow you to use the blinkers as brake lights also to aid in being seen. A great investment in your life.
BLINKER TIPS
Blinker, it's a matter of resistance, the new bulbs don't complete the sequence, get a badlands load equalizer, if using the blinkers (hazards) get the equalizer 2….
BIKE SHUTS OFF INTERMITTENTEDLY
A brother, Chrispfrid’s, scooter shuts once in awhile. It could be fuel supply or electrical. I suggested checking grounds for an electrical solution. If a ground connection, especially on a rubbermounted bike, comes loose or is rusty, it can break connection with vibration or under ideal circumstances. Usually when a rider is escaping a mad husband, mother or father. Here’s some other responses:
I've been down this road myself.
Let me tell you a little story. I had a '91 1200 Sportster that would just quit running,I would be running along then boom DEAD.I was Stationed at Davis-Monthan AFB in Tucson at the time and was riding to San Berdoo about twice a month. The Dealer in Tucson had it for a week and could not find anything wrong with it. Then I was riding through Fontana one day and it up and quit. Lucky for me, I was a block from the H-D dealer. I pushed it to the service shop, they took it in and gave me a ride home. As soon I got in the door the dealer called. My bike was fixed. The Battery Ground wire was bad, took the mechanic five minutes to check it and five minutes to fix it, the ride home was ten minutes.
Goes to show, always check the easy stuff. It was my fault. I had taken the wiring apart so I could get the rearpainted black. I bought my Sporty through the Military Sales program and they sent a red one. I wanted black but I was hungry for a new Harley and always liked Sportys.That mechanic gave me a piece of advice electrical troubleshooting is like plumbing, you got a source (power) and a drain (the ground).
good luck.
–Drifter
HE SAYS FUEL LINES CAUSED IT
I've had inline fuel filters cause those symptoms. If you have a good screen on your petcock you don't need an inline filter anyway.
FTW,
–Stroker
CHECK YOUR GAS CAPS
Hey Chrisp : Check your gas caps . They gotta be vented . Every time you go for a ride crack one open before you start 'er up and see if that solves your problem . Two minutes is too soon for the fuel in your fuel line to start boiling because it's too close to one of your jugs, I would think .
If I was you, I'd have a look into that also .
–Art Parry
NO FUEL PROBLEM
Hey Chrispfrid,
Bandit's right. No easy way to find the problem. I doubt it's a fuel problem, though, especially in view of the fact that you've changed everything out. The only thing you DIDN'T mention was whether or not your fuel float and the valve it controls are OK. Sometimes they stick. Sometimes the valve needle isn't set in the hole of the float correctly.
Though this probably isn't your problem, I had a buddy with an old bike that had a weird problem with the float. Turns out the float was one of those old brass, soldered jobs. It had a tiny pinhole in it. So, the guy would park his old shovel. The gas would run out of the carb like it often did in those days. Carb float bowl would be empty. Cool. Messy, but no real problem for a bike that was already lubricating the street for 1/2 block in each direction whenever it was parked.
So he'd want to go for a ride. He'd upright the bike off the kickstand, and turn on the gas, after a few miles the carb float would fill with fuel and sink to the bottom of the bowl, making the engine suddenly run really rich, puke black smoke and sputter. We looked all over that electrical system and couldn't find a thing (duh).
Finally after looking at the carb about the 11th time, one of the garage layabouts (the guy had free beer in his garage…it was always crowded over there) started playing with the float, which had been laying on a newspaper by the bike. He shakes the thing and hears gas sloshing around inside. We'd found the problem. A new float and my bud was good to go. See? Layabouts actually are a good thing sometimes. Just make sure you've got enough beer around and lawn chairs set up far enough away from your workbench so you don't trip over their size 13s as they're giving you generally useless advice.
The problem with YOUR bike is probably electrical. One thing you can do is get in a dark garage, turn your ignition on, and start wiggling wires. Sometimes you see a tiny arc. Don't run the engine in a dark, closed garage, or you'll solve the problem in a way you never thought you would.
I can see the headlines now, “Biker Found Dead, Slumped Over Motorcycle, Victim of Apparent Bizarre Secret Sexual Ritual”.
Wife says, “I Never Knew He Was Like That.”
If you don't see arcs, idle your baby in the driveway and just start wiggling stuff. And DO check that ignition switch. It's mechanical. Mechanical things go south, especially on Harleys. That switch should be a little warm, maybe after the bike runs for a while, but if it's HOT you've probably found the problem….Don't forget the wires under the tank and in the headlight shell if you can't find anything else.
One other thing. If memory serves me right, your bike has breakers instead of fuses. Next time your bike stalls, if possible, get your ugly mug down close to the bike, near the seat, and listen. A few seconds after the bike quits you might here a quiet little click of a breaker resetting. If one of your breakers is resetting, figure out which one it is. Then you've narrowed the problem down to the circuit(s) that breaker is protecting. You've got an intermittent short somewhere (bare wire connector touching the frame or a ground wire or other bare wire directly). Now, at least you'll know where to look, and what to look for.
Don't forget, the problem MIGHT be the breaker itself. When they get old, they can trip at too low a current load. Breakers are pretty simple devices, but they are mechanical, and can get old, corroded and crappy, and start doing weird shit.
Good breakers can and will save your bike! Basically, what happens when you have a short in your electrical system is that it turns part of your wiring harness into a light-bulb filament. It's gonna get hot and burn up if something isn't done, and done quickly. A breaker senses that additional load in several different ways, but the most common design is for the thing to sense a heat build-up(it actually gets hot, like a fuse). Instead of melting, like a fuse, a tiny switch to open, breaking (that's why they call it a “breaker”) the circuit before real damage is done. After the breaker cools down, it resets closed again. That's the click you might hear. Harley has had some problems with breakers over the years, so that might be it…but keep reading.
As for what you're experiencing, if the breaker for your ignition circuits gets hot, or vibrates too much, or there's a little moisture built up inside it, whatever, and trips, your engine quits mysteriously. A few minutes later, just as mysteriously, you'll be able to start the thing again (the breaker has reset). Hmmmm…sound familiar?
Just to make things more complicated, be aware that a short in, say, your taillight, for example, can actually cause your engine to quit under the right circumstances. Just like the big blackout in the Northeast a few years ago, a bad circuit can cause a breaker to trip, which causes another circuit to misbehave causing THAT breaker to quit. And on and on. Cascading breakers.
I've actually seen old bikes with electrical problems that had a few breakers in them that sounded like popcorn. The breakers started popping like a pinball machine, setting and resetting various parts of the wiring harness, until we found the problem. In one case the owner had put an accessory wire on the positive battery terminal to run a radio or something. The connector would touch the frame only when he was under way. The main breaker would sense the short connection and trip. Everything would go dark. The guy would roll to a stop, lights, engine, everything dead. Thirty seconds later, when the breaker reset and the connector was no longer touching the frame, he could roll again– For a few minutes. We finally spotted the place where the bare edge of the connector was about 1/8 inch from a frame tube, and you could see where the paint had disappeared from arcing and friction.
Good Luck!
–Hiway
VAPOR LOCK CHECK
To Chrispfrid:
Check for vapor-lock. The next time it acts up (if you can catch it in time), pop your gas cap and see if the bike responds. Even if you don't catch it and it still dies, pop the cap and then see if your bike will fire back up.
Having sealed the tanks, it's possible you've partly clogged the ventilation. Or your gas cap could be defective. But first; check and see if popping the cap helps at all.
Good luck man
CARB BLUES
CV/THUNDER SLIDE CARB TUNING
Your bike IS running a bit rich. My bike was set up exactly like yours for a long time, until I got cams and some other stuff. Thunderslides make your bike run rich, but not across the RPM spectrum, so it's difficult to tune out the richness without knowing how you ride.
If you're running “a little” rich, it won't hurt your bike, BUT it will blue your pipes a bit more quickly. Harleys actually don't have much problem running a little rich, but running too lean will damage your engine pretty quickly from too much heat. If you look at your plugs, they should be a nice neutral greyish/brown color. If they're white, you're running too lean. If they're dark grey/black, too rich. On a TwinCam, the two plugs should be the same color (older dual-fired bikes with mechanical advances often ran differently from front cylinder to back to the point that many riders would even use different heat range plugs in the cylinders).
To figure out how you're running, go get yourself a plug wrench. Go find a straight road a couple of miles long and cop free. Get your bike warmed up, and then go down that road at about 70 or so in top gear. You're right in the middle of your power band and RPM range if you do that. Pull in the clutch, cut your engine off (don't let the engine go back to idle). Roll to a stop and pull your plugs. Now what color are they? Adjust your main jet accordingly. One thing you can try BEFORE changing jets is to move your jet needle down one notch (you have a stock carb, right?) That'll lean things a bit. Get a manual. The procedure to do that is in there… None of what I've suggested is very hard for a decent mechanic, but if you need to look in the shop manual to see a picture of a exotic tool like a screwdriver so you can find it in your toolbox, you may want to get help from your local shop.
About that exhaust popping, if you have stock carb and cams, you have an exhaust leak, like Bandit says. The easy way to find it is to run your engine, and use a cigarette or if you're a born-again hippie, some incense, or something else that will create a stream of smoke. Hold the smoke generating device around the joints of the exhaust system (make sure the bike is heated up) as you rev the engine a little. You should see disturbances in the smoke when you're near the leak.
Make sure everything is tight. If things seem tight, and your exhaust still pops, you probably need to replace the exhaust gasket where the pipes meet the head. Be careful about cranking down on the bolts. Do it evenly, from side-to-side, in three stages and use a torque wrench. If you bust or strip one of those studs, you're in for some seriously expensive repairs.
The clamps on where your mufflers clamp on to the header pipes can really be cranked down on, usually. Make sure those are tight, too!
Ride!
WHAT WILL WINTER DO TO MY CARB?
Grape Ape is pretty much right. If your bike is running OK in the summer, don't rejet it for the winter. Your CV Carb is a good one and will work pretty well in most conditions.
Grape Ape is probably right about the coughing and sputtering. It's due to ice in the veturi throat of the carb. Ready for a small physics lesson? OK.
When air (or any gas for that matter) is compressed, it gets hot. Ever put your hand on an air-compressor tank when it's running? Warm, isn't it? On the other hand, when air pressure is released it cools down. Ever notice how the metal end of an air hose gets cool if you let air out of it for a while? Or how a rattle can of paint gets cold as you use it? There's all kinds of rules here, named after the guys that originally discovered the effects, but just take my word for it. This is the way it works.
So, in your carb, when air goes through the tight throat of the venturi, the pressure drops as the velocity of the air increases (OK. OK. It's called the Bernoulli Effect). The carb is designed to do this so the air flow will pull fuel from the float bowl with slight vacuum. At low RPMs you have high vacuum and the chance for icing is very good. If the air is moisture-laden, you actually get a tiny little rain storm inside your carb. If it's cold enough, that water coming out of the air stream freezes into ice, causing blockage. Your bike coughs and sputters because it can't breath.
In the movie Grape was talking about, Jimmy Stewart (playing Charles Lindbergh) caused the backfiring to heat the carb and melted the ice. In modern piston-driven airplanes there's actually a lever called “Carb Heat”. You pull this lever out and it opens some vents around the exhaust manifold that vent hot air back to the carb area, to prevent this sort of icing, stumbling, and stalling. Pilots are a lot more concerned about this since they're flying at altitudes where it's cold, and the air is thin. If YOU have engine trouble you can pull over and signal for help. If a pilot has engine trouble you can usually tell he needs help by the flaming wreckage… Catch my drift?
Solution for YOU? Put 'er in the garage for a while before you start her. If you don't want to do that, get a heating pad and wrap it around the carb/air cleaner for a while. Maybe even a hot-water bottle. Or have your girfriend put one boob on each side of the carb for 1/2 hour before you go for a ride. That should keep things warm enough, although, if you take the last option, I'm guessing YOUR LIFE is gonna get real cold and icy for a while. Once you start the engine, the heat from the engine should compensate for the heating pad (hard to say, since we don't know what your air-cleaner set-up is like).
Riders ride TwinCams in the winter all the time with little or no problem. You get her warmed up right and she'll take care of you (just like a good woman).
Ride!
Twin Cam cylinders on an Evo?
Nope. Don't do it. Not only would you have to bore the cases, as Bandit says, there are other problems, too. Twin Cam bore x stroke is different (it's shorter stroke, wider bore). Not only would you have to do all kinds of case machining, but you'd have to change your pushrods, crank, lifters, and a bunch of other stuff. If you did manage to get all that done, you're going to have to fab custom motor mounts to get the top of the engine bolted into the frame properly, if you're going to put the new monster in an Evo frame (shorter engine).
Also, there are oil return passages in the Twin Cam cylinders and cases that don't exist in the Evo, and the way the two engines deal with oil vapor internally, and back pressure from the stroking pistons is completely different. The pushrod angles are completely different, since the Evo uses a single cam and the Twin Cam uses, well, twin cams. You'd have to experiment with pushrods of the right size. These angles cause an adittional problem of the pushrod barrels not sealing properly because the barrels would hit the heads at the wrong angle, allowing the cork or rubber gaskets to squirm. Now, how about that intake manifold, and rejetting the carb? And the combustion chambers are completely different shapes. I could go on and on……
I'm guessing, just running up the machining and other costs in my head, by the time you got done, you'd be pretty close to the price of a good, used Twin Cam engine. But then you'll have to figure out how to mate it up with your Evo-style tranny, and figure out the electrics, since Twin Cams use an entirely different electrical system for ignition timing than Evos. But now it's getting crazy….
If you're doing this just to say you've done it (wouldn't be the first time someone has done something just to prove it could be done) then go for it, but bring a roll of dead presidents big enough to choke a really big horse.
Really, your best bet, if you're looking for a bigger displacement engine is to either just get your cylinders bored by someone who knows how to bore motorcycle cylinders (it's different than boring a car engine block), or go see one of your friendly aftermarket dealers. Evos have been around a long time, and the aftermarket pony-boosting upgrade parts are rock-solid, tried and true. It'll be a lot cheaper in the long run, and a lot less of a headache.
If you're trying to go on the cheap, for a boring job of a couple of hundred, another hundred or so for some new pistons, wrist pins, and rings to fit the new bore, and then a new gasket set, and maybe some bigger carb jets, and you're good to go. No muss. No fuss.
TWIN CAM AND EVO OIL FILTERS
Yes Sir, Running a twin cam filter on an evo is bad business it will restrict the flow and make oil build up in the block and spit oil out of the breathers and most certainly damage the motor . it is true that running a evo filter on a twin cam will result in more flow due to less filtration, I am not sure that is better but I don't think it will hurt anything. I am not surprised that the guys at the dealer wont recommend anything other than the stock replacement equipment ( due to liability ). The Devil
HEAD GASKET PROBLEMS
If you are blowing head-gaskets, be sure you have changed the studs. Evo style motors need the studs changed each build, or at least every other build. Also, if you have high compression pistons, overbored cylinders, etc. you may have to have stud inserts installed in the cases. If you want a trouble free top end, just plan on having the inserts installed along with good high compression studs and any quality head gasket will do, even a stock one.
I am lucky enough to have a friend who knows what he's doing install them for me cheaper than I would have spent on a install kit. Just take the top end apart to save the shop time and you some money. Also, be sure to FLUSH the motor real good so any of the driillings won't get caught up in any bearings before even thinking about firing it up! Johnny,
Glad to hear the dealer stood up and took responsibility for the crash. If you didn't do the three things I told ya to, I'm guessing the dealer probably called the district rep to see what he was liable for, after you complained, and the district rep told him to get his shit together. The Harley hierarchy is pretty strict, and the district reps can kick some serious ass if they want to. Any time there's a question about how to deal with a situation that's going to get pricey, you can bet the dealership called the rep.
When I worked at the dealership in San Francisco, we had a similar situation happen. The delivery company was delivering brand new bikes to us in 2003. As luck would have it, the minimum-wage kid who's job it was (he worked for the trucking company) to roll the bikes off the flatbed truck dropped a brand new $25K SE Screamin' Eagle Deuce (remember the black and gold ones?) on its side. Of all the Buell Blasts he coulda dropped…NOOOOOO..he drops the most expensive bike on the truck.
So, we call Harley to find out what to do (most dealers will call the district rep to get a judgement call). The district rep said, “Fix it. No questions asked. We'll deal with insurance later.” Some bolt on chromy stuff was scratched. No biggie. Easily replaced. The real problem with that bike was that the frame was dinged. Not bent, just the gold powder coat was scratched under the primary case, where you wouldn't even see it if it wasn't pointed out to you. You can't patch powdercoat. We had to completely disassemble the bike and put in a new gold powdercoated frame, just for a 1/2 inch scratch. Frames normally take about 6 to 8 weeks to get on order from the factory. This one was delivered in just over 2 weeks. Harley wouldn't have it any other way.
The customer was pissed at the dealership, even though it wasn't our fault, but he was OK with the situation later when the owner gave him some discounts on stuff, just to be a nice guy. And we fixed the bike good as new. At Harley's direction.
You hear a lot of bad stories about Harley. A lot of them are deserved. Others aren't. Sometimes they come through like the company we expect them to be. Funny how you don't hear about that much…..
I worked in a good dealership where the owner was all about treating customers right. Yeah, he probably charged to much for his bikes, but when it came to him standing up and doing the right thing for service and warranty, he was one of the best. On the other hand, I've visited dealerships that just plain sucked. The employees were clueless and treated customers like shit.
I'm kind of on the fence about this whole FTF thing. I think what the problem is that it's not the factory that's abusing customers (they're too busy suing the competition). It's the dealerships that are abusing people.The factory controls the way the stores look and how much the bikes cost, but they can't control some bonehead salesman's shitty attitude. With Victory and some of the other companies breathing down Harley's neck, and Harley itself now making enough bikes to pretty much meet demand, the dealership employees had better lighten up…
Ride!
EXHAUST PROBLEMS
REVERSION CONES OR BAFFLES
Bandit's right, those cones work pretty well under the right circumstances. Bandit's fix of cutting up some baffles works better, for my money. Check out this website:
http://www.bigcitythunder.com/
There's a really good section in there called “Exhaust: The How and Why”. It should enlighten you.
The thing about having the baffles down at the end of your pipes allows for some gas compression and other magic that rings (which is what those cones are) right next to your heads doesn't allow.
To be really honest with you, the stock heads on TwinCams don't breath very well. Twin Cams are bigger, displacement-wise than Evos, and yet the ports are smaller (thanks to the EPA). I wouldn't add any restrictions right next to the heads. You'll experience some significant power loss, I'm guessing. If memory serves right, those cones were for Evo and earlier bikes. The company may be selling them for Twin Cams, but it wouldn't be the first time a company kept marketing something that was of marginal actual value.
Here's a basic lesson in the way your gasses flow through your heads. In a 4-stroke engine there are, well, 4 strokes. If you look at one of those animated cartoons, everything is very neat and tidy, with each valve opening to let gasses go where they should. Neither valve is ever opened at the same time as the other one. That all works well and good if your engine is idling.
Once you really get rolling though, performance engines actually need to have both the intake and exhaust valve open at the same time during parts of the stroke. It helps with something called scavenging. Scavenging is when the departing exhaust gasses create a slight vacuum in your cylinder and actually help pull the new fuel/air mixture in for the next big bang.
Obviously you want to have a little scavenging, but you don't want to pull the charge through TOO fast. If you do that, you don't have a full volumetric charge when the valves close and the spark plug fires, resulting in a crappy-running engine. It's gotta be JUST right. So, you want to have a baffle. But the baffle has to be designed right to prevent reversion.
What happens with “reversion” is that the departing exhaust gas pulses hit something (like a misplaced baffle) and bounce back up the header pipe, to collide with the next pulse of exhaust gases, ruining the scavenging affect, and causing your engine to run like crap at certain speeds. This can be noticed by weird “hunting” or flat spots in your acceleration, among other things.
Exhaust pipe technology is a bit science and a bit magic, and a whole lot of experimenting. Anyone can make drag pipes. Not everyone can make an exhaust system that works.
Take Tunderheaders. Not that I have any particular love for them above other exhaust systems that are just as good, but you'll notice, for instance, in Thunderheaders that the baffle isn't straight across the pipe. It's at a steep angle. This is to diffuse the exhaust gas “lump” and prevent it from bouncing back, full force, up the pipe. So if you can't get a Thunderheader or other good exhaust system, what do you do?
Drag pipes (straight pipes) are meant to allow free flow of exhaust gasses for drag bikes, so they're really good (assuming your bike is tuned for it, which most street bikes AREN'T) at redline. But they run like crap down in the lower RPMs. Put a baffle in a drag pipe, and you'll get better low end torque, but your top end will suffer. How much time do you, as a street rider, spend at top end? Very little, I bet. So, get yourself some baffles like they show on the above website and start experimenting.
Now the secret is that you have to get just the right amount of back pressure from your baffle, and you have to set the baffle in the pipe in just the right place so that the pulses bouncing off the baffle are not slamming into your exhaust pulses as they exit the head. It sounds simple, but it isn't. You'll have to play with it a while.
Bandit's suggestion will work pretty well. A little back pressure for a street bike is a good thing. You'll be surprised how much better your bike will run, and it's likely your popping problem will almost disappear.
Maybe you're worried about cosmetics of putting a bolt in your beautiful pipes to hold the baffle in? Drill the hole at the point half-way between horizontal and vertical (225 degrees). You'll be surpised how hard it is to see.
Ride!
Hiway
REVERSION CONES ARE COOL!
That was a pretty good explanation of the how's and why's of an exhaust system. Just one problem. The part about the “power cones”. There is NO way that adding power cones will cut power in any engine. Period.
Following the supplied exhaust system explanation, everyone can see the advantage of having a exhaust that pulls a bit of the mixture out of the cylinder. Oh, the exhaust and intake valves are open a small number of degrees, at the same time. It's called overlap. Valve timing is fixed by the cams. It doesn't change through the RPM range, as was at least implied.
Anyway, when the exhaust valve opens the pressure in the cylinder (caused by a variety of things from piston movement to heat and gas expansion) pushes the exhaust out of the port. Keeping the physical size of the port smaller keeps the velocity up, remember the venturi in your carb? This velocity helps to pull more gas out of the cylinder, as the peak pressure drops off very rapidly. Motors like the Shovelheads don't make as much power (but can with mods and RPM) partially due to the ports being too large and the gas moving slowly (relative terms). The smaller ports in the TC are part of the reason they make a LOT more power than the older design. Inch for inch.
Now take a modified engine with open exhaust. As the valve opens the gas dumps into a big hole. It expands to fill the space and the velocity goes way down. Bad thing for scavenging, performance follows. The cones keep the exhaust gas from “seeing” this big space by creating a small pressure lump. Not a big restriction though so it's doesn't hurt below light speed. The cone also does something else, it creates a venturi, just outside the valve. Again increased velocity, good scavenging, good performance. The exhaust systems seem pretty simple at first glance. Don't let that fool you. There are many things to know and I sure don't know them all. There are two pressure waves to design for. They travel at different speeds, very different. There is a heat driven pressure wave and a sonic wave to design for. I let the big guy's to the brain work. It hurts too much. But something I can understand are dyno numbers, exhaust emissions tests, cyclinder temperature comparisons, ok there's a bunch of stuff you can look at to make a decision about your exhaust. Or, you can trust the people who make their living doing it. For the most part I do that.
I'm starting drift and ramble so I'll stop now 🙂
–Dago
ABOUT THOSE CONES
Uhhh.. OK. I agree with you on some points, and agree others need to be clarified. You definitely know what you're talking about. I would dig finding a bar and doing some bench racing with you. But I want to make my own points.
First, let's talk about the powercones and the pressure drop they create. What you're talking about (the pressure drop) is called the Bernoulli Effect. An increase in velocity creates a decrease in pressure AT THE VENTURI (the throat of the powercone or carb). Upstream of the venturi, if the thing isn't placed right, you can actually have a DECREASE in gas velocity, caused by the pulses of the engine, the shape of the port (or whatever the gas is going through), etc. Unlike non-compressible fluids like water (in engineering terms, gasses are compressible fluids) something happening in a venturi does not necessarily have a positive affect on things upstream. The pressure drop is an indicator of gasses upstream not moving as fast as in the veturi area. If the veturi is not designed or placed correctly, it becomes restrictive. That was the point I was trying to make. Ever seen someone put a velocity stack on a bike and it starts to run weird? That's what I'm talking about. It SHOULD make things better, right? Not always…..
One of the things that Jerry Branch (a guy who's been tuning Harleys for longer than most of us have been alive) does is to show how the shape and angles of a venturi throat can affect air flow around it. I've seen where he checks the vacuum (usually measured in inches of water) in a veturi and around it. Venturi will be pulling a pretty good vacuum, but the area just in front of it isn't doing so good, due to turbulence, pressure waves, and other things. He then puts some dollops of clay around the venturi. Immediate pressure drop and velocity increase, causing better flow throughout the system. What that indicates is that if the area “upstream” of the venturi isn't designed right, the venturi will actually cause problems in overall flow, even though there is a significant pressure drop right in the veturi. So, how does that work with powercones?
If the powercone is in the right place, it CAN help with scavenging, but you have to be careful that the powercone is specifically designed for, and placed in the correct place in the header area. Frankly, I'm skeptical about them when it comes to TwinCams. If you've got numbers that bear out the facts that they work, and increase USABLE HP and torque, then I'll buy you a beer and apologize to you and Willie G, and the makers of powercones for my heresy.
Second, I didn't mean to imply that cam timing changes as the RPMs change. It most definitely doesn't (at least not in Harleys…but in some late model cars it actually DOES, believe it or not). However, the cams' effects on the airflow does change as the velocity of the gasses passing by the valves and through the heads change. That's why different cam grinds (profiles) have different effects at different RPM ranges. You're absolutely right that lift, overlap, duration and timing are all factors in the way your engine makes power and when. Agree with you completely there. And of course, the cam profile must match the engine design, or you'll actually make matters worse. Maybe being a little humorous, but you put a cam for a AHDRA bike in a stock twin cam, and tell me how she runs…hmmmmm…or not.
Exhaust system are a big factor, too. How many people do YOU know have bought that really cool exhaust system for their bike, only to find it doesn't do much. Why? Well, you know…all KINDS of reasons, but all of them come down to how the gasses are flowing through the system.
Now for the thing about TwinCam heads. Twincam heads DO make more power than EVO or previous heads. No argument there. They do that for a lot of reasons. The shape of the combustion chamber for one (but let's not go there, today), the size and angles of the valves. The bore. The stroke. On and on.
The point is that they could make a lot MORE power if they weren't so restrictive. Yes, they DO increase velocity in the small exhaust port areas, but the general common knowledge from S&S, Branch Flowmetrics, and even Harley-Davidson themselves is that they'd do a lot better with bigger exhaust valves and better ports. You'll note, for instance, that all performance companies are selling less restrictive heads. Even Harley has a Screamin' Eagle catalog (you have to ask for it) which has heads that have 1340 (Evo) style ports for Twincams. These heads are for “race applications only”, but we all know that that means.
I've had friends that have put these bad boys on their bikes, and there is a definite, significant power increase. The engine simply breaths better. While there's a lot to be said for tuned ports, a tuned port that's too small doesn't do you much good, right? So, if you think about it, if you've got an exhaust area that's increasing velocity due to its size, and you add even more restriction with powercones….well, I'm guessing it won't be too good.
Of course, one of the traps that many Harley riders fall into is to buy a bunch of performance parts that are each quite good, but don't work well together, creating an engine that's tempremental and persnickety as a race horse.
We've all had friends that have spent butt-loads of money on the engines, looking for that max horsepower number, only to find that the HP is made at redline, so the bike dogs until it's really rolling…. Gotta pay attention to EVERYTHING..
The overall thing that Brian should keep in mind is that these mods should be done by taking the whole view of what your'e doing to the engine, and making sure everything will work together. It always concerns me when someone find a single thing in a catalog and thinks that will take care of business. Brian apparently HAS fallen into the trap of modifying the engine without a plan. If he didn't, he wouldn't be getting the symptoms (black puffs of smoke, popping, stumbling) that he is. I'm just trying to keep him from throwing good money after bad.
I absolutely, positively agree with you on the reversion pressure-wave thing. YES, there are two types of waves coming back up the pipe. The reason I didn't really go into it was because I was making a point about drag pipes and baffles. And besides, I barely understand that black magic myself (gotta do a lot more reading and talking about that before I'll stick my balls on the table for that one).
Now, Rebel, I'm not trying to piss you off. I'm just trying to get Brian some info. The thing to keep in mind is that there is no single right answer on this stuff. If there were such a thing, you might have one company out there, say S&S, who sold one set of cams, and one set of heads, and everyone would go there to get the performance they needed. It's a friggin' jigsaw puzzle, and you're right, EVERYTHING is important….and it IS complicated and sometimes hard to figure out. The best tuners in the world are STILL fucking around trying to find that perfect engine song….more power to 'em! There's also a lot of hacks, who will look you straight in the eye and tell you their product is the best thing to hit the street since the headlight. Those are the guys we need to keep an eye on.
Ride!
Phil's New Exhaust Is Popping On Deceleration
Phil,
Bandit's right. It's VERY likely you have an exhaust leak. At any rate, when trying to find ANY problem on a bike, always check the simple, cheap stuff first. You'd be surprised how many “serious” problems turn out to be something pretty easy to fix. A lot of riders will take their bikes in, all worried about their baby, only to have a shop charge them an hour's labor to tell them it took 45 minutes to find the problem and 10 minutes to fix it (plus 5 minutes to drink coffee and fill out the bill).
In your case, make sure all your exhaust fittings are tight, and tightened EVENLY. For instance, if you crank down on one bolt, and then the second, you're setting yourself up for a leak. Tighten one side a little, then the other, then back to the first side, and back to the second…until you get everthing tightened evenly. If it's a strap type clamp, make sure it's tight enough. You can usually really crank down on those, and rider often don't get them tight enough. Comprende?
What causes those pops is air being sucked INTO the exhaust system on decelleration. The air combines with gasses that are hot enough to burn, but don't normally have enough oxygen to ignite. With the addition of unexpected air from the leak, they ignite, causing the pop you're hearing. Under normal conditions, the gasses have cooled enough by the time they reach the end of the exhaust pipe so they don't ignite there.
If you're getting a pop on decelleration, get a cigarette or other smoke-generating device (don't use a joint…it's terribly illegal and a waste of good weed). Also, you want something that will generate a stream of smoke, like a cigarette. Setting the garage on fire to get a billowing cloud of smoke misses the point a bit, and won't help you find your leak.
Start your bike, and while it's idling, let the smoke from your cigarette waft by the various joints in the exhaust system. Maybe rev the bike a little while you're doing it.You will often find a place where the stream of smoke is disturbed by little puffs of exhaust coming through the leak. You've found your leak. If you've got everything tightened right, it COULD be a bad gasket. I know it's tempting to reuse gaskets that look OK, but keep in mind, once they've been used once and compressed, they may not seal right the second time around….
There are other reasons exhaust systems pop, too. You didn't say how your injectors were mapped or what cams you're using, but those can cause minor pops, too, that area result of cam overlap and injector mapping. What can happen with hot cams and remapped fuel injectors is a weird problem that takes some fixin'. Like I said, though, check the cheap stuff first.
Ride!
–HIWAY
ABOUT THAT SHOVEL PROBLEM
Have you checked the springs with your timing weights? It SOUNDS like your engine is either running really lean, like Bandit says, or your timing is too advanced. If the springs are weak, it'll advance your timing before it should, making your bike run really hot. There are several marks on a Shovel's flywheel. Are you sure you're set up with the right one? Check your manual. There were early wheels, late wheels and single fire wheels.
Check those things. But from the sounds of it, it's a lean condition. If you're having to mess with your idle screw the way you say, you've probably got a pretty good-sized intake leak…. Check your plugs. If one is white ashed and the other one isn't, the side with the white ash is where the leak is, between the manifold and the head. If they're BOTH white, your leak is probably between the carb body and the intake manifold…Easiest way I know of to check for leaks is to take a lit cigarette and let it smoulder near the intake manifold while the engine is running. Look to see if the cigarette smoke gets sucked in to a crack anywhere. DO NOT use a fatty to do this. It's incredibly illegal…….and a waste of good fatty.
Ride!
–Hiway
GLIDE REFILLS
By “procedure” do you mean how much oil, or how to do the fill? Bandit's right for the amount. Make sure you put exactly the same amount in both sides. If one is a little low, you'll get handling problems that'll drive you nuts.
How do you do it? First, you're going to have to drain the old oil, if you haven't already done so. Unscrew the screws on the sides at the bottom of each slider, let the oil drain. After you've drained the oil, put something up to block the squirt, and bounce the suspension a few times to get the last bits out. Put the drain screws back in.
Now get the front wheel off the ground. YOu MUST get the weight off the front of the bike. If you don't, you'll fire that bolt/ plug across the garage into the dark area behind the furnace, after it riochets off your forehead.
Remove the bolt/plugs in the top of the forks at the top of the triple trees. Pour the oil in. Put the bolts back in. This can be a bit difficult because of the spring tension, so what I often do is have a friend push on the bolt until I can get it to catch the threads in the top of the fork leg. You're ready to roll (after you get the bike back off the brick you propped it up on).
Ride!
–Hiway
STOCK FRAME OFFSETS
Joseph…
Yes, Dynas (and many other Harleys) have a built-in tire offset. There's nothing wrong with the frame or the bike. I've asked a lot of Harley company types why that is, and have gotten a lot of different stories. The one that pops up most often is that the offset at the rear tire allows the belt to line up without offsetting the engine/tranny, which would cause a weight distribution problem. By offsetting the tire, they allow the engine/tranny weight to stay center-line. The offset isn't enough to really affect handling to any degree a typical Harley rider would feel.
The symptom that is felt most often (not very often, but it does happen) is that the bike will oscillate back and forth slightly as you go down the road, as the gyroscopic effect compensates for the offset. MOST bikes oscillate (it's actually called gyroscopic precession) a little, but the rider rarely feels it because of bumps in the road and textures, and trying to avoid that lady on her cell phone in the Lexus that's drifting into your lane.
Since Harleys don't handle that well to begin with, and their steering is “slow” an offset is no big deal. Were there that kind of offset on a short wheel-based, quick-handling bike like a Buell, you'd have real tracking problems, with the bike wanting to flop down on one side, and not wanting to turn in the other direction, and the wobbling would be pretty pronounced. Big, long Harleys with lots of rake don't sweat it too much.
I had exactly the same experience you're having once on my Softail. A few years ago I was measuring things up to see if I could get a fat tire installed at the rear, and found an offset. I freaked out, thinking my frame was bent or something. The local Harley mechanic just laughed, patted me on the head, and told me to calm down, then explained everything to me (he does that a lot…at least I keep him laughing).
The interesting thing is that if you own one of the pre-2003 Harleys that have 130's stock on the rear, the 150 upgrade kit that Harley sells actually puts MORE offset in your rear wheel, so the fatter tire will still clear the belt. I've got one of those kits on my bike. I've noticed that the front tire wears off center, but other than that there are no bad things going on, as far as I can tell.
Ride!
–HIway
NorCal
THOSE DEER ARE DEADLY!
When I used to live in Wisconsin back in the 70's, I hit a medium-sized doe with my car one evening at dusk. The deer probably weighed maybe 80 lbs. I was going about 50 MPH. The deer peeled back the hood of my car, broke the whole front end out, and broke one of the motor mounts (by impacting the car, not by just going postal on it). This car was a full-sized, '70-something Ford Torino four-door, built like an M1 tank, like they used to build 'em in those days. Totalled the car (of course the car was only worth $500.00, so that might have had something to do with it). But that car went directly back to the recycle yard where I'd bought it in the first place. This time there was no reprieve.
Another night, a friend of mine caught one of those babies in his lap when he was out motoring around on his bike one night. Not only did it knock him off his bike, but the deer survived. They wound up all tangled up on the road together. The deer, in its panic, stomped the hell out of him before it finally found its feet and ran away…. This guy was about Bandit's size, and when I caught up with him the next day, he looked like, as they say, he'd tried to beat someone's fist to death with his face.
Most people don't know it, but deer hooves are sharp as razors, and deer are incredibly strong (remember, they can jump over a 6 foot fence without even getting a running start). You get up close and personal with Bambi, and she's gonna take you out.
I tell ya, whenever I ride in your neighborhood, or in areas where I know there are deer, I try to get off the road before dusk. They're cute, but they'll ruin your day if you tangle with one! Either the impact will get you, or you wobbling around in surprise and then going down will make your evening go south pretty quickly.
Ride!
OIL QUESTION
Oil question, we always use 70wt oil on our older bikes, like Florida our climate is almost always hot and 60 or 50 are too thin, more so when they reach very high temps, been using 70 forever, works fine….Kendall, Castrol or even revtech make very good 70 wt. Hope all this helps….
RAISIN PIE FILLING FOUND!
Hey Boss,
Karp's is now owned by H. C. Brill(CSM) and markets your Raisin Pie filling under their Henry & Henry brand name.
H&H CROWN FILLING # 3496 Raisin
You should be able to get it from your local bakery supply company or restaurant supply company.
H.C. Brill Company, Inc.
1912 Montreal Road
Tucker, GA 30084
770-938-3823
1-800-241-8526
–Stroker
John, S&S 113s like about 28 degrees of total ignition timing. At 3000 rpm, the F mark with the vertical line should be at the very front edge of the timing hole, actually just beyond the front edge. If you are static timing (engine not running) put the T:F mark at the same position (just disappearing at front edge of hole) and that should get you in the ballpark. Set advance to be all in around 2500 rpm or so, rev limit about 6200. We always recommend checking timing with a timing light at speed. Get yourself a long clear view timing plug and put a few extra threads on it (or cut back in a lathe) till it actually touches the flywheel and you should be able to view the mark nicely. James SimonelliJames SimonelliManagerCommunications & Events VOES Woes There is a lot of confusion as to what will happen if we shit-can the VOES switch on our Harley's ignition systems. I've heard folks say it could cause spark knock, it could give a ruff idle, it could cause poor acceleration, it could cause… Let us see if we can determine just what a vacuum advance does and maybe dispel some myths in the process. Vacuum advance whether mechanical or electronic performs the same function, it introduces a second advance curve to our ignition system timing. We start with a 'normal' advance curve based only on engine speed (RPM). Then under high vacuum conditions we 'switch' in the new timing curve which will increase the amount of advance, or decrease the rpm of the advance, or both depending on which ignition system we are using. So when do we 'switch' in this mysterious high vacuum timing curve. High vacuum is more a function of how far open the throttle plate is, than engine speed. If you have ever driven a manual shift car with one of those annoying “shift now” lights you know that if you accelerate the light goes out, no matter what your engine speed is. This imitates the action of the VOES switch. The shift light comes on at high vacuum. Open the throttle is low vacuum. Close the throttle is high vacuum. Just like the action of the car's shift light. By advancing the ignition timing when not accelerating it yields a more efficient burn and reduces exhaust emissions… ah, you knew the EPA would have something to do with this bag-of-snakes. So why not just leave the ignition advanced all the time? Because under high load conditions too much advance will cause pre-ignition and detonation (spark knock) that can lead to sever engine damage. Remember high load (acceleration) equals low vacuum. Under low vacuum we switch OUT the vacuum advance timing curve, it's all starting to make sense now. Now remember, if we leave the vacuum advance curve ACTIVE we cause spark knock. So if we shit-can the VOES switch we are always in the 'normal' advance curve which is tuned to NOT cause spark knock. Myth number one gone. The only way eliminating the VOES switch will cause spark knock is if you permanently force the ignition into the vacuum advance mode. Vacuum advance has little to no effect on ignition timing at a normal idle (around 900 rpm). Yes idle is a high vacuum condition, but remember it is an advance CURVE and is also based on engine speed. Myth number two down. Removing VOES can cause poor acceleration? Remember, the vacuum advance timing curve is 'switched' out under acceleration. Myth number three down. Ok, so just whatthefuck does eliminating the VOES do? When you're putting along at a steady speed you will have a little higher exhaust emissions with out it. That's about it. Yes, the cleaner burn can also affect gas mileage. However, considering many ignitions vacuum advance affec
