• Dana

Back to work

I didn't get a chance to work on the bike much in the last few weeks. Turns out real life has a way of getting in the way. But I did manage to get all of the cam bushings done and installed.

I also decided to replace the pinion race in the crankcase. It was pretty pitted up and it wasn't pushed in all of the way so the thrust washer behind the pinion was loose. That can't be good. I was definitely a little worried about pushing it out and pushing in a new one. I'm always a little nervous about pushing steel into aluminum, and the drive shaft and pinion shaft are pretty important and they need to line up perfectly in order for the flywheel to spin nicely.

I put the crankcase in the oven at 275 and waited an hour. Took it out and put it on the floor to knock out the old race and it just fell out. So that was easy. To push in the new one I wanted it as straight as I could get it in. There's no way to line hone the pinion and drive races together so it needs to be pushed in perfectly. So, I built a tool. I took a hunk of 1.75" round steel and turned it down to fit in the drive race and the pinion race with 0.001 clearance. Then I assembled the whole crankcase with the pushing tool in the drive race, the pinion race was on the end of the tool, and put all that in the oven at 275 for another hour.

After it got hot and expanded nicely, aluminum expands faster then steel, I put the crankcase on the press, put a socket under the pinion to support the aluminum case and pushed on my home made pushing tool, through the drive race, and pushed the pinion race right in.

The new pinion race installed in the crankcase

It didn't work, the race didn't go all the way in, and I didn't want to force it in. So I took it all apart and knock the race back out while it was still hot. After it cooled I was able to look at the housing and saw that the very bottom 0.100" was smaller then the top. That explains why the old race wasn't all the way in. I wonder how long it was like that.

Easy fix, just took a small hone and LIGHTLY touched up the bottom to the same diameter as the top. Go SLOW and measure often. With that done, I just repeated the whole process and pushed in the new race. It took all day but worth it.

On to the flywheels

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