Bonneville Bike Updates: Back into the Forks

(this is a slightly abbreviated version of update letters sent out to the sponsors of our grass roots fundraising efforts for the next trip to the salt flats) Thanks for reading!

After setting the bike on the ground (right side up), with the reduced rake the forks actually went up and down.  It was also apparent that the extra weight showed the spring rate in the forks to be not up to the task.  Nick took them apart and went up one spring rate and decided to try the low-friction SKF fork seals I bought a year ago, put away and promptly forgot about.  New oil, and the forks back in gave us back some adjustment of preload, but we will need to see what the extra weight of the turbo and bodywork will show us.  A Hayabusa, the source of the forks, is a big bike, but considering the displacement and power, somewhat demure in the weight department.   Salt had had it way with the upper steering bearing so we replaced that as well.  The first test ride should be interesting. 

Now we start the process of putting things back into the bike.  The area behind the motor is the most comparable to the abdomen in a human.  It has the heart (fuel pump), the artery (fuel delivery line), the vein (fuel return), the major muscle group that makes it work (battery) and the stomach (fuel tank).   All these things have to coexist in the same area without conflict.  This conflict can take a number of forms, one being the attempt to have two things in the same place at the same time.  Another is the conflict that arises when something metal gets across a positive and negative, resulting in sparks and fire.  Since the stomach contains gasoline, this is a very real concern.  To try and envision every type of component failure that may release the battery, the fuel tank, the pump,  wires and lines takes a bit of time and effort.  We don’t have the violence associated with a Funnycar or Dragster, but the sustained vibration and occasional jolt from the track surface can be enough to set undesired events in motion, not to mention the routine servicing of the bike and transporting it on our marvelous roads all over the country. 


The fuel tank receives a new location and will serve as the seat platform as well.  Moving the ballast back and down allowed the reconfiguring of the tank to make access to the fuel pump a bit easier, and not require the removal of the tail section (and its myriad screws) to refuel the bike.  Since the seat had gone through quite a number of changes in height and padding, using the space occupied by that padding seemed a reasonable course of action.  We had to add padding to the seat for last fall because evidently not enough of my butt was visible from the side.   That was the first time in quite a while someone asked to see more.  For my money, usually too much was in evidence. 

Reducing the capacity of the fuel tank was possible since the consumption rate of the bike only needed two and a half gallons plus what is in the fuel lines, making the 4 and a half gallon capacity of the original tank unnecessary.  This allows a bit more room in the middle bay area for other things. 

2013_4_8gastankcardboardtest   2013_4_8gastanksetup

Building the tank entailed a series of patterns that gave enough capacity, but didn’t rub on things.  A fuel leak with the starter solenoid, fuel pump and battery directly below would be frowned upon.  This tank also needed to be welded inside and out for strength as I will be sitting on it.  The stereo began behaving oddly during the final welding being done inside the tank.  It would repeat the last track of the fifth CD in the player.  Not the first and not the fourth.  At least it wasn’t turning the phones on and off like the last big aluminum job did. 


Once the tank, with its attending returns, drains and sump was nearly completed, we needed to reroute the cooling system.  The radiator is in the back of the bike up in the tail, so there is about eight feet of plumbing needed to reach it and return.  This all has to run through the bay containing the fuel pump, battery, etc.  Some creative routing came into play.   It is a bit of a puzzle as the availability of condition “O” tubing that can be bent into the tight curves needed is limited.  I have only found it once and it was shipped to us by accident and I couldn’t find it again. That means a lot of it needs to be made with preformed silicone curves and straight pieces. Care must be taken to avoid abrasion and burn-through as hot coolant spraying around tends to be a distraction and should be avoided at all costs.


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