If they are properly maintained, have proper belt/chain tension, not overly abused and don't have a manufacturing defect they usually last quite a while.

 

Going to go ahead and pull the tranny as there's a gasket leak from the inner tranny cover. How do I get the bushing that the inner primary seal rides on off the main shaft ? It seems to be a press fit.

 

The bushing can stay in place unless it is damaged. just pull and replace the seal, along with the quad and starter shaft seals..

 

Thanks John, I wanted to pull the entire transmission out the trap door side to replace the leaking trap door inner gasket but was having problems getting the 2 piece puller to get the inner race bearing to break free of the mainshaft so I pulled the trap door off the main and counter shaft easily enough. I further inspected the inner race and I can see a bit of wear on it so looks like I will have to dremel it off after all.

 

If you are going to split that with a dremel, be sure to slobber a lot of grease on the bearing. That will keep a lot of the grindings out of the bearing. Dont forget to clean everything well. When you put it back on it should be pressed on and leave .100" clearance between it and 5th gear.

 

Thanks John, .100 sounds to be about the size of the quad seal.
Just curious John in your shop have you's ever pulled the trap door off the 2 shafts to the way I did it successfully to replace the gasket without needing to replace the 2 trap door bearings?

 

No we have the tools to pull it apart the normal way and it is a lot easier to do it that way. Plus we get to inspect all the gears, etc. that way.

 

I was reading up on side preasure being applied to bearings when they were pulled and needed to be tossed.

I will be replacing all the bearings including the needle bearing. The video I have is made by Video Manuals it shows the press used for installing the 2 trap door bearings , putting the tranny case in the oven and freezing the big main shaft bearing and dropping it in and using the press to install the needle bearing, unfortunately the tranny is still in the bike and can't be heated so was thinking to tap the needle bearing into the case, pressing in the trap door bearings and freezing the big main shaft bearing and tapping it home with appropriate size socket to only come in contact with out ridge of bearing .
What is the way you utilize to install the needle bearing, big mainshaft bearing and 2 trap door bearings while the tranny is still in the bike?

 

Doing it that way probably won't work. I see the case cracking as there really isn't a lot of meat there.

 

K John, so far what I have managed to get done is first I took the trap door with clips out I put it on the wood stove for 15 minutes , turned it over and bearings fell right out, put the new bearings in the freezer for 1/2 hr put the trap door back on fireplace and bearings fell right in and bottomed out so that part is done.
I got the bearing race pulled off the main shaft using the two half round thin lipped puller.and pulled counter shaft and main shaft out.
I tapped the 5th gear in to the case and off the big bearing.
I tried getting the big clip off the big mainshaft bearing but my c-clip tool won't stretch across to reach both holes so tomorrow I will have to find a bigger set.
I'm also going to see about getting some dry ice for shringing the bearing to pull out.
Tomoorow at work I'm going to see if I can find a some pipe to make up a puller.

Question: the 2 opened end bearings in the 5th gear are suppose to be installed to a depth according to the Jims tool and of course I don't have that tool, when I tapped the 5th gear inward with a mallot and block of wood I pushed in the end seal (damaged ) and I don't think it could have pushed the bearing but was wandering if you know the depth for each end? My Clymer doesn;t say anything other than use Jims tool and my factory serv manual is MIA.
Thanks