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Which model had this gear cover
Posted: Wed Sep 29, 2021 12:26 am
by malmac
I bought a secondhand gear cover out of Germany.
Attached is a photo of the 2nd hand gear cover in the front and the original gear cover from my bike.
Someone has made an adapter plate to convert the older cover so it will accommodate the later model generator.
Which model does the front cover come from?
Mal
Re: Which model had this gear cover
Posted: Wed Sep 29, 2021 9:23 pm
by malmac
Well another question re the front gear cover.
How high should the breather plate rubbing surface sit proud of the machined surface which is outside the wear path?
Thank you in advance for your help people.
Regards
Mal
Re: Which model had this gear cover
Posted: Thu Sep 30, 2021 6:38 am
by malmac
malmac wrote: ↑Wed Sep 29, 2021 9:23 pm
Well another question re the front gear cover.
How high should the breather plate rubbing surface sit proud of the machined surface which is outside the wear path?
Thank you in advance for your help people.
Regards
Mal
Jan from Salis has told me .2mm, which rather surprised me, as it is not much.
But he is a good man and I never doubt his advice.
Thanks Jan.
Re: Which model had this gear cover
Posted: Thu Sep 30, 2021 9:27 am
by Daves79x
I found that my R50's breather plate surface on the cover had been machined, I had to remove the circlip from the spring to get the plate to contact the rubbing surface. Works fine that way and later bikes did not even use the circlip. Just a b!tch to install with the engine in the bike!
Dave
Re: Which model had this gear cover
Posted: Thu Sep 30, 2021 10:11 am
by jwonder
Mal,
The one with the tachometer drive cover missing is the upgraded timing gear cover. It was upgraded June of 1967 and the service bulletin is available in our library at
https://vintagebmw.org/library_data/250.pdf. So, if your motorcycle is above the serial numbers listed in the service bulletin then that is the right one.
I am not sure why you have a adapter for the generator, because my generator from my 1967 R 69 S (with the tachometer plate) fits perfectly on my 1961 R 50 S timing gear cover without the tachometer plate. So it may be an older timing gear cover or the newer timing gear cover was setup for a 12 volt system? Not sure.
Re: Which model had this gear cover
Posted: Thu Sep 30, 2021 12:21 pm
by malmac
jwonder wrote: ↑Thu Sep 30, 2021 10:11 am
Mal,
The one with the tachometer drive cover missing is the upgraded timing gear cover. It was upgraded June of 1967 and the service bulletin is available in our library at
https://vintagebmw.org/library_data/250.pdf. So, if your motorcycle is above the serial numbers listed in the service bulletin then that is the right one.
I am not sure why you have a adapter for the generator, because my generator from my 1967 R 69 S (with the tachometer plate) fits perfectly on my 1961 R 50 S timing gear cover without the tachometer plate. So it may be an older timing gear cover or the newer timing gear cover was setup for a 12 volt system? Not sure.
Thanks James
I also asked Jan at Salis but he was not sure. He suggested I contact Mark Huggett.
Mal
Re: Which model had this gear cover
Posted: Thu Sep 30, 2021 12:25 pm
by malmac
Daves79x wrote: ↑Thu Sep 30, 2021 9:27 am
I found that my R50's breather plate surface on the cover had been machined, I had to remove the circlip from the spring to get the plate to contact the rubbing surface. Works fine that way and later bikes did not even use the circlip. Just a b!tch to install with the engine in the bike!
Dave
Hi Dave
If your cover was machined, should I assume it had been built up first with weld prior to being machined?
Apparently a N.O.S cover measured up at having a factory rise of only .2mm, so not much to play with before cutting below the surface of the machined land.
Mal
Re: Which model had this gear cover
Posted: Thu Sep 30, 2021 4:17 pm
by Daves79x
No, just machined down to likely remove scoring from some catastrophe. There is enough spring tension to push out the plate far enough to contact the surface, but the circlip must be removed.
Dave