We grappled and struggled with the oil bag system for months, going back and forth. I studied bags in dressers, the serpentine baffles and the notion that the pump would initially pull the oil up outta the bag like siphoning gas from mom’s sedan.
Additional thoughts from a reader regarding ground clearance:Depends on the track, spring set-up, suspension set-up, tire pressure, strategy, wedge and wheel jacking, blah, blah, blah. Might know you would ask your southern friend that question. If you are looking for ground clearance and ground effects and such go to: Yes, I know it's long. Whatever the ground clearance, make sure it can roll left and rIght (lean angle) without touching the ground. I'd say 1.750 inches ground clearance but if one of the tire goes down, we don't want the frame to get on the ground as it's going to be bad enough anyway. –Pablo
Berry Wardlaw of Accurate Engineering sent me detailed engineering drawings from the biker bar down the street, Slippery Shirley's Saloon. Seems he was road testing his performance dresser, when he ran past a cop at over 100 and kept going. He stopped at this saloon and started drinking Jack Daniels and drawing oil bag interior designs. With the bar napkin blueprints in hand he walked into the sun to board his hot rod bagger. He was met with the cop who clocked him earlier. It all went downhill from there.
I went from cutting an oxygen bottle in half to studying Jap bike bellies. We fitted our nitrous bottle, the Hamster air dam and measured twice. We shit-canned the air dam, the NASCAR theme and the earlier, smaller Nitrous bottle mount. We decided to make the bottle fit as close to the top of the oil bag as possible. Then we measured twice again and rolled to the Wilmington Iron Works shop down the street.
It’s a cool old building and we told them the width needed to be 8 inches and the depth 1¾ inches, and it needed to be 26 inches long. We carefully bent a chunk of brass rod as a guide. They cut the piece out of the 14-gauge material we provided, then their brake wouldn’t bend anything over 24 inches. They hauled it down the street and called me from the shop, “Is the angle or the width critical?”
That was a damn good question.
“The width is more critical,” I responded.
The next day, the bend was available. The width was critical. If the angle had been more severe, we would've been cool, ‘cause we had some ground clearance to play with. But they went the other way flattening out our slab of sheet metal until it wouldn’t hold a half-quart of oil.
More and more I attempt to look at blunders or obstacles as benefits. They give us more time to contemplate design, refine structure or detail construction. We reviewed our concept again and decided to run a wider oil tank to the center of the bottom frame tubes on either side. I bent another chunk of 1/8-inch brass rod and rolled over to San Pedro Sheet Metal. Art could handle the task and in a couple of days I was looking at the initial shape or our baby, except he bent it out of 18-guage. That haunted me.
Now came the difficult part. We had to devise the interior serpentine baffles without schooling or a map, placement for the fittings, an aerodynamic bow and stern, fill cap, drain plug and mounting. First, I contacted Darin at Bungking.com for fittings and rubber mounting brackets. They do a helluva job. One kit is designed specifically for oil tanks with a fill cap, and three 1/8-inch pipe bungs. Jeremiah stopped at an auto parts and scored a drain plug with an interior magnet and I made the drain bung with ½-20 threads.
The tough part was placement, but we started with the baffles to prevent all the oil from slogging forward or to the stern and out of reach of the feed inlet. Then I made a template of construction paper for the nose and cut out the sections with a plasma cutter.
I started with the nose and one baffle to ensure the shape of the 16-gauge sheet metal during construction. Heat can do strange things to metal. Next, I cut the rear of the oil bag to allow any low-flowing air to escape the undercarriage of the bike with ease. Hope I know what I’m doing. That’s an oxymoron!
With the stern “V” ground smooth I used the belly as a guide to scribe another panel of sheet metal to close in the stern.
I tested capacity, initially holding my hands over each end and Nyla poured pint measuring cups of water into the breach and we counted. We were confident that our crazed design would contain at least 2.5 quarts. We were cool. Then I added more capacity with the bow and less cutting the stern.
We positioned the bag so it would meet with the nitrous bottle. “Nitrous bottle is 17.64″ tall and 5.25″ in diameter,” Colonel Wardlaw informed me before the bottle arrived.
So the oil bag stuck out in front of the frame by about 4 inches. We rolled the dice on this design element several times. We questioned whether we should form a scoop or air dam to shove the nose down. That could become an immediate air resistor and slow the vehicle, so we went for the slippery notion. Get the air through and around the bike as comfortably as possible, and we’re hoping our design plus the shape of the nitrous bottle will accomplish just that.
Next, we wrestled with the fittings and I fucked up. There’s that adage: Measure twice cut once.
I found a perfect bung for the drain and the perfect spot. I started to weld the bung on the outside and then inspiration struck like a Corona bottle to the back of the head. I could make the overall shape even more air user-friendly by placing the bung on the inside. I did and welded it permanently, only to realize five minutes later that I was preventing all the oil from being able to drain with my ¼-inch lip on the inside. Done deal, move on.
That error was a quick reminder of the “measure twice” adage and I slowed my movements—always a good thing. Then I struggled with the feed, return and vent. I discovered that if I ran an external feed, I would be forced to run an oil line from the distant stern over the top or through my ¼-inch belly pan up around the transmission to the oil pump. Or I could run it up over the side of the oil bag on the outside, which seemed critically dangerous to have our feed line hanging out in the wind before it reached the oil pump.
Then it dawned on us that we had a very large surface on the top, free and clear of obstacles, directly below the oil pump and between the engine and the transmission. We had to make a steel tube extending from the BungKing bung to near the bottom of the oil tank for pickup. I fought with that notion, guessed and second-guessed my design. It’s like the major artery to the heart of the motorcycle. It had to be perfect. We made the steel tube extension then ground it several times and finally extended it some more. We were grappling with molding the line close to the bed but not against the sides or on the floor to pick up grit during a record breaking run on the salt.
Next, we decided to weld the return bung comfortably in front of the front motor mount just below the oil filter mount on the Accurate Engineering Panhead engine. Actually, all the mounts and bungs were perfectly accessible and convenient. Sometimes that’s a bad omen. We also mounted the fill cap right in the front, again extremely accessible—amazing. Many of these efforts were part guesswork since I didn't have my Accurate engine for oil fittings, oil pump or oil filter return line placement.
It was time to mount the beast under the frame, and again I needed four hands. I looked for possible mounting locations. Scary again. I didn’t want them too close to anything, extremely secure and so they wouldn’t interfere with the engine or tranny, terrifying. Jeremiah and I messed with this for hours. We encountered a couple of problems. The top wasn’t flat for some reason. We suspected warping and ignored it and kept moving forward. The more we worked, the more bothersome it became. Also, the frame tubes weren’t parallel, which fucked with our measurements.
Some of the distortion was caused by welding the bungs into the center of the top plate after drilling it. Then I stamped “IN” next to the feed bung so we wouldn’t fuck up the lines. That dented the top plate. There was our glitch. We removed all the tacks, detached the lid and hammered the bastard straight again—sort of against my bad, black dot code. We all try to do something right the first time and call it, done, right? Wrong.
I learned a valuable lesson from John Reed, the retired CCI master designer. He said something to me one day, while we were discussing Bonneville last year.
“I need lots of fasteners,” John said, “since I often install and remove a component hundreds of time.”
That hit me like a bolt of lightening. In other words, John tried any new component hundreds of times, before he called it finished. Now, instead of trying to plan, make and install something once or twice, I know to take long moments of reflection and do it over and over until I’m sure it’s right. Thanks, John.
This time, the top plate fit and it was flat. The bungs reached and were cool. We tacked them. The oil tank came together, and then we delivered it to Rick Krost from U.S. Choppers for final TIG welding.
In the meantime we needed Nyla back on the bike to work on the peg mounting. I needed to work on the drive chain guard and make sure Valerie’s feet would be completely clear of the chain. I used stock H-D rubber pegs and some two-inch tabs, supported by 45-degree chunks of steel I bagged from the metal fab shop next door.
I tacked the tabs then Jim Waggaman rolled into the Bikernet Headquarters to steal a ’53 Lincoln bench seat I’ve been trying to unload since our La Carrera race across Mexico. He carefully lined up both peg mounts perfectly, and then I welded them into place.
Hang on! Next, we need to make the chain guard and start to work on modifications to the gas tank. We’re burnin’ daylight!
Here’s the desired, determined schedule: We’re shooting for being ready to go to paint at the end of June, just two weeks away. I’ll be a nervous wreck until then. Then I’ll go find a white, soft sandy beach to lay on for a couple of weeks with a case of Coronas. Our goal is to be up and running by the end of July. That gives us August for tuning at Gene’s speed shop, and then we’re off to Bubs Motorcycle Speed Trials in Bonneville. Gulp!
