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Old 11-21-2011, 12:26 PM   #55
Joined: Jul 2008
Location: Melbourne
Oddometer: 1,070
Originally Posted by Wirespokes View Post
I wouldn't install the steel roller, supposedly there's a possible problem with that mod, but don't recall specifics. The stock rollers hold up well, so don't bother.
The shift mechanism is a good idea and easily swapped. Your bike is right around the time a lot of those things were changed - are you sure yours doesn't already have it?
No, I am not sure. Is there a way to tell without cracking open the box?
I think it was in this thread (could have been one of the others I read) that Anton said (loosly paraphrasing from my memory) the later shift mechanism started on some bikes half way through 1981 and was in most bikes by 1982. Mines a Feb 1981 bike.

Besides the false neutrals, how does your shift? If clunky, it should be shimmed anyway. And if you replace the large front output shaft bearing you should, at least, check the shimming. And if you're planning on taking the bike on tour to rougher roads far from home, I'd recommend replacing that bearing while in there, if nothing else. Since I can fix my own, I don't worry about the bearings and re-use them if they look and feel good. But that bearing is most likely responsible for most tranny rebuilds, so to be safe, replace it while you're in there.
Clunky is a bit of a relative term on these boxes isn't it? Gearbox shifts reasonably well and is less clunky than many other airhead 5 speeds. Seems fine to me.
I'll look into the front output shaft bearing.
It looks like my want to avoid shimming is completely unrealistic- fair enough I'll have to shim it. Shims are cheap so maybe one of each,
.2mm, .28mm, .38mm, .5mm?

Have you read anything about working on these tranny's? There are a few sites that go into detail, and I'd recommend it.
I'll hit google again tonight after work.

Originally Posted by disston View Post
I don't think it is reasonable to expect that you can open any of these transmissions and not have to shim the shafts when you put it back together. Supposedly you can only replace the bearings that either feel notchy or loose but those have to be shimmed and since that is happening you should shim all the bearings. It is also reported that the factory did not do a very good job of shimming these boxes so if you are opening one you are advised to be ready to shim it before you put it back together.

Now you are replacing one of the gears? You have to shim the whole box. Period.

How many miles on this trans?

Ok, shim I will do if I go through with this. Sorry for the unrealistic want.
the miles are completely unknown for the bike and the box.
For the bike, at least this when the speedo seized a while before I bought it

My engine number (6251767 ) doesn't match my frame number (6252171), which I originally thought meant an engine swap but was told a while back that bikes of this vintage didn't necessarily have matching numbers in the first place.
The previous owner couldn't remember much about details like this and didn't do his own work on the bike. I know the guy who sold this bike to the previous owner, and he is our local airhead parts guy/guru, but it was a while ago and as he sells a lot of bikes, so he can't remember any specifics other than 'if it needed anything done I would have done it before I sold it'. He remembers it coming in for a few services and minor repairs over the previous owner's ownership.
It looks like I any more info about this bikes history is unavailable to me.

Thanks a lot for the respones,
gotta run to work now.
1974 R90/6
1981 R80G/S
1994 XLR250R
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