4 Speed Transmission Overhaul R60/2

[Seek]

Are you sure about the bearing fit on the input shaft? Of course you want a good fit and in case of doubt you could add some loctite retaining compound. But the bearing riding up the shaft? The bearing is being pressed down continually by the stiff spring from the shock absorber. I could see how a poor fit of the bearing in the housing would cause interference problems between the bearing and the intermediate shaft gear. But that is where a proper end float helps, so the shaft can't move up that far.

[pinbill]

Ohh no..... Glad this isn't my daily driver. It looks like input shaft shimming is a point of contention between Vech and the authors of the Barrington book. Not sure what I am going to do. Here is what I understand so far:

The factory shimmed the input shaft with the curved oil washer. They shimmed the output and intermediate shafts with shims. As long as the output and intermediate shafts are shimmed correctly the trans won't pop out of gear or burn the bearings. The transmission will operate fine. Shimming the input shaft is a change to the design of the transmission.

If the input shaft isn't shimmed, the forward bearing can work its way out and rub the face of the forward intermediate shaft gear. When putting the case cover on you have to be careful that oil washer #18 doesn't wobble around.

If the input shaft is shimmed the bearing can't work its way out, but the kick start spring can bind. The kickstarter may not return all the way. The Barrington book and Duane Ausherman sometimes cut the small kick start spring to compensate for this.

If the kick start doesn't bind I don't see any harm in shimming the input shaft. I may shim the input shaft so the gap is .3mm and cut 1/4 of the kick start spring. Right now the distance between the intermediate gear face and the forward input shaft bearing is .5mm. If the forward bearing works loose I would still have .2 mm between the bearing and intermediate gear face. There would be more than enough clearance for the bearings. The kick pedal should not bind.

[pinbill]

I spoke with Blaise Descollonges about the .85 end play in the input shaft. He has seen it before but it is rare. I am going to shim the thing to .004" and run it.

[Seek]

That doesn't sound quite correct about the inputshaft not being shimmed from the factory. According to the Workshopmanuals it was the intermedate shaft which rarely got a shim. Endfloat was 0.2 mm for input and outputshaft, 0.2-0.4 mm for the intermediate shaft. Much later, almost at the end of production a service note mentioned tighter endfloat, 0-0.1 mm for all shafts. There are various sizes shims #18 available. Max size is 1 mm if I remember correctly. I had to add a 0.2 mm shim to get to a total endfloat of 0.15 mm.

I don't know about shortening the kickstart spring. Never heard about that. But I am open to learn something new. I can't quite understand why that would be a problem. Do you mean the light spring #16? I certainly did press down the fitted ring #17, as that is how it is described in the manual.

[pinbill]

Hey Seek,

Duane Ausherman talks about the kick start lever not returning fully on his website w6rec.com. Its under: /2 series, drivetrain, transmission service, repair. It is at the very bottom of the article where he talks about chopping the small spring. I am not sure how often it binds up. Mine was OK using the original thinner spring.

I meant to say the input shaft was shimmed with the curved oil washer not with shims on the bearings.

I also compressed spring #16 and washer #17 with a threaded rod to get the input shaft end play measurement. I got a concerned when it was over 2mm. I was glad to confirm that it happened sometimes although rare. It may have been assembled on a Friday at 4pm back in Munich in 1964. LOL. In the end I felt it made sense to remove the end play.

Anyway the cover went back on smoothly, the shims slipped right in, the oil washer seated correctly, and the kickstarter works well. The input shaft and the output shaft are very smooth. At first the output shaft was stiff. I tapped it with a mallet while everything was still warm and the shaft loosened up immediately.

It is going to be bench tested tonight and put in the bike on Sunday. I may have to find something else to work on until I rebuild the Earls Fork and replace the head bearings.....

I really appreciate all the help and experience from the BMW community.

[Seek]

Great joy when it comes together! I just assembled mine last week for the second time, after I discovered a weard clunking noise when rotating. That prooved to be the shockabsorber I installed, a nice second hand item. Nice in theory not so nice in reality.