The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: tunnelrider on September 12, 2015, 01:47:12 AM

Title: Gearbox cover and bearing fit
Post by: tunnelrider on September 12, 2015, 01:47:12 AM
Hi all,

I'm hoping someone can tell me through their own experience....

Is it worth re-using a gearbox cover that has a slight (.05mm) interference fit at room temp on the shaft bearings?  If cost of a new cover wasn't an issue I wouldn't be asking....  

The new bearings can fit in the cover receptacles about half way by hand and I can imagine not much force/heat would be required to fit the cover.  The cover was able to be removed without having to heat it.

The box used in the Clymer manual also had an easy remove/fit and there was nothing said whether this was bad.  Obviously though the cover is supposed to be heated to 100 deg C to enable fitting.   There is slight evidence of the outer bearing races spinning in the receptacles, but no grooves or notches have been worn into the cover.  I could use a glue to hold the bearings to the cover but I guess a future cover removal would be a real PITA.

To buy a new cover would be about 20% of the bike's value.

Any comments/ advise would be gratefully appreciated.

Thanks,
Dan
Title: Re: Gearbox cover and bearing fit
Post by: Tony Smith on September 12, 2015, 02:00:18 AM
I would use it and maybe use a little engineering adhesive to seat the bearing. The last time I did the bearings in my R100's gearbox - about 1994, that bearing was a "slip fit". A howling bearing is not one of the reasons I took the R100 off the road in 2013.


Alternatively you could have the case machined and put an insert in, but unless you can do this yourself, or have friends that can do it, the cost is likely to be competitive with a serviceable 2nd hand cover.
Title: Re: Gearbox cover and bearing fit
Post by: tunnelrider on September 12, 2015, 03:02:14 AM
Good man Tony!

9 years is good enough, can you remember how many km's you did on the R100 in that period?  Thanks for posting another helpful reply on this from my previous topic I mentioned it on.
Title: Re: Gearbox cover and bearing fit
Post by: tunnelrider on September 12, 2015, 03:27:25 AM
By the way Tony,
Have you got your R100 on the road after 2013?
Title: Re: Gearbox cover and bearing fit
Post by: Tony Smith on September 12, 2015, 06:12:05 AM
Quote
Good man Tony!

9 years is good enough, can you remember how many km's you did on the R100 in that period?  Thanks for posting another helpful reply on this from my previous topic I mentioned it on.

I can't be sure because during that period the original instruments were replaced and I have lost any notes I kept in relation to the odometer on the original failed speedo or what was on the 2nd hand replacement. All i can say is that it would have been in excess of 100,000km
Title: Re: Gearbox cover and bearing fit
Post by: Tony Smith on September 12, 2015, 06:22:58 AM
Quote
By the way Tony,
Have you got your R100 on the road after 2013?

Therein lays a tale.

The simple fact is that my R100 is worn out, knackered  and stuffed. It has an enormous number of total kilometers and is a ground up rebuild prospect only.

That is the reason I rebuilt the r65 that sat as a wreck under the house for 20 years - it was only 10 years old when parked and I took a punt that its "fundamentals" would be good enough so that it could be stood up fairly cheaply.

I got the last part wrong and ended up spending a little more than twice what I thought I would to get it running.


But I digress.


The R100 is the next project but this time it will be done "right" I essentially plan on having a brand new R100RS come out the other side of the rebuild/restoration. To that end I am laying into stock stuff I know I will need, like new fork legs (and if I can find them, new sliders too) Brake and master cylinder rebuild kits etc. etc.

I am planning to make some concessions such as having my original cylinders nickasil coated and switching to the later rings so as to not chew the lining up, I will also switch over to post 1985 rockers and pushrods.


It's a long term project that I really do not expect to see finished until after I retire.

In three years time I'll have owned it for 40 years.
Title: Re: Gearbox cover and bearing fit
Post by: tunnelrider on September 12, 2015, 04:10:23 PM
Quote

I can't be sure because during that period the original instruments were replaced and I have lost any notes I kept in relation to the odometer on the original failed speedo or what was on the 2nd hand replacement. All i can say is that it would have been in excess of 100,000km

Wow, sounds like you had a bleepin good time on your R100.  100 000km is more than enough service for my bike I think.

But I'm thinking I'd prefer to put the gearbox back in knowing it's been done as good as possible and since I can actually part with the money for a new cover and earn it back, I'm currently thinking I'll buy a new cover.

Thanks for your advice, it's still very tempting to go down the re-use road too! (i.e. I'm gonna think about it over a Sunday)