Technical Page
Pilot Bottom end Rebuild.
After a big end bearing failure last year and a main bearing failure at the 24 Hour race, I had 2 cranks to rebuild and 2 bottom ends to assemble. I sent my cranks off to PCP Offroad in Phoenix, AZ.
Of course you need a shop guide for this procedure so I won't include any torque specs or specifics like that.
GAMM!
The 1st order of business is to clean everything! Make sure any bits of old gaskets are removed from the mating surfaces of the case halves. Some people will use a grinder with a soft wheel but I would never risk damaging a case by using something like that. I clean my surfaces with a brand new razor blade held at a very steep angle, I work it a little at a time and slowly "shave" away the gasket and then slowly remove the residue. Make sure the case halves fit together perfectly, if you can see light between them when bolted together loosely, they need to be lapped to fit tightly.
The next step is to install the new main bearings in those perfectly clean cases. I will tap mine in very gently with a soft mallet till they are going in perfectly straight, the press them in only exerting force on the outer bearing race.
Instead of buying the special(read expensive) tool from Honda, I did the Dirt Cheap method and built my own. I cut off a piece of an old clutch bolt and drilled it. It fits in a sleeve welded to a long threaded bolt. A small nail connects the two and allows a bit of flexibility and also acts as a shear pin if something does not line up right.
The object here is to pull the crank into the main bearing. The long threaded bolt has a nut on it that I tighten up against some large washers, it pulls the threaded piece inside the crank and pulls everything towards the outside. Notice the pipe is pushed against the inner race of the bearing. This keeps the ball bearings in the bearing from getting any pressure while assembling.
7/07/03