Sportsters…… I love ’em. Light, tight, quick, and always ready for a street brawl.There’s just one problem: The availability of aftermarket parts. Although theaftermarket industry has yet to fully embrace the Sportster rider as a marketingforce, Baker Drivetrain is one company that is bucking the trend.
What you see before you is the recently released Baker XL6 6-speedtransmission for your Sportster or Buell. I’ve had this one in my bike for just acouple weeks now, and I’ve got to say – this is THE TICKET for anyonescreaming down the highway or wanting to raise some eyebrows in betweenstop lights.
The unit comes packaged in polystyrene and complete with transmission,shifting drum, forks, pins, low-effort detent spring, a template for minor casemods and installation instructions.
My test sled was my Softail Sportster, built just last year. It’s a 1200 XL with astock 30-tooth pulley on the secondary. At 80 mph, it feels like you’re doing 65with about a 550 rpm drop. The top gear is a .86 overdrive, as opposed to thestock 1-to-1 gear ratio of the stock unit. This is interesting because it gives youbarn burners out there the option to drop the tooth count on the secondary pulley,gain about 8 percent torque through the gears, and still retain the stock overallgear ratio at the top end. It’s also got a trap door about as thick as the armor ona battleship. As anyone who races Sportster motors knows, the week point ofthe stock engine is the trap door. Baker’s is made of about a 1-inch-thick pieceof T-6061 billet and it’s about five times stronger than the stock door.
So, let’s get to the installation.
First, we remove the shifting arm from the outside of the primary and remove theprimary cover to reveal what you see above. At this point, we need to removethe clutch basket.
With the help of a spring compressor from Custom Chrome, we remove the diaphragm spring.
We now have access to the two shaft nuts that have to be removed to allow forremoval of the primary chain, clutch and front rotor/sprocket assembly. You willneed an impact wrench and a couple large sockets to get these off. The impact/air wrench takes advantage of the inertia of the motor and basically bangs thenuts off rapidly without you having to hold or jam the assembly while you muscleit off with a torque wrench. There is one thing to note – the transmission mainshaft nut is a counter clockwise thread, so don’t beat on it all day in the wrongdirection trying to get it off.
For this project, the rotor was placed back on the front shaft just to keep itsomewhere clean, but you can take it off for working in this area. It’s magneticand wanted to stay on the stator, so we gave it a good tug and it came right off.
What you are looking at in the photo above is the stock shifter prawl, detentplate, detent and detent spring. The stock plate is held on with a spring clip. Asyou will see later, the Baker model is held on with a screw.
Remove the detent plate, shifter prawl and detent spring (loose in the photoabove) and get ready to unbolt the four bolts on the trap door.
Once you unbolt the four bolts holding on the trap door, the entire cartridgeassembly is removed by pulling it toward you. The stock unit is above. Note thedoor thickness and webbing on the cast piece.
Once you have the unit out, you can see the stock 5th main gear (still in thecase) with the main shaft, counter shaft and shift drum bearings still in the case.Note the template at the top – we’ll get to that in a minute.
The next step is to modify the case. Baker sends a template to guide a diegrinder or Dremel tool to make clearance for the 6th gear, which is sunk into thetrap door. We mounted the template (as shown in the previous photo) andisolated the area with some shop towels. This is a messy process, so you wantto make sure you keep the shavings OUT of the case.
To properly modify the case, use a Dremel tool or a die grinder with a mediumburr. The cut you will make must follow the contour of the template as shown. Theback-cut must run about 3/4 of an inch. I went back 1 inch just to be sure. YouDON’T want the gear in contact with the case. When complete, remove the rags,blow it out with air and clean with a brake cleaner or other solvent to flush out allthe shavings.
Now we’re ready to prep the transmission. We must remove the stock 5th gearand place it on the Baker countershaft. It is held in place with a snap ring, so itwill be helpful to have a good set of snap ring pliers. YOU MUST PUT THEGEAR ON IN THE SAME ORIENTATION AS STOCK. Wear patterns occur inthese gears and you need to keep the wear patterns in the same orientation asbefore.
Next, we must place the shift forks on the drum and mount them in place usingthe drum pins and cotter pins supplied with the kit. The manual details the exactorientation of the forks.
The forks are then put into place over the two shafts as shown above. The newdetent plate is then fastened onto the end of the drum on the right hand side.This photo gives you an idea of how thick the door actually is. You can also seehow the top gear set is recessed into the door. At this point, you will also need tore-attach the detent, which restrains the detent plate.
The shifter prawl also needs about .100 inch ground off the tip to make clearance on the new door.
Next, the gear set was slid back into position in the case and bolted down.
The prawl was put back in place and adjusted per the service manual, and thelow effort detent spring was installed. I highly recommend you get a Harleyservice manual for this job. Adjusting the shifter prawl and the proper bolttorques are all critical to reassembly.
The clutch basket, front sprocket and diaphragm spring are then re-installed,and you are ready to re-mount the primary case. Remember to get a newprimary gasket and hold it in place with a little grease to make re-assemblyeasier. Torque down your primary cover, adjust the primary chain per the servicemanual for proper play and you’re ready to rock.
A couple of side notes. If you have a pre-1991 XL, ask Baker about upgradingyour 5th gear to eliminate any gear whine. Reverse pattern shift drums are alsoavailable for those who like to upshift by slamming their foot down, rather thanpulling it up.
Later – Digital
