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R75/5 transmission

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Victor Doherty
(@vjdeidolon)
Posts: 5
Active Member
Topic starter
 

Can I put a 1975 5speed BMW transmission on a 1972 BMW R75/5 ?

 
Posted : 04/12/2020 22:28
James Strickland
(@8053)
Posts: 423
Reputable Member
 

Yes. However, you must use the clutch release mechanism from the 5 speed and you will need to fashion a jumper wire to ground for the neutral switch. The 4 speed neutral switch grounds inside the transmission. You will also need to use the shift lever from the 5 speed. Many years ago I installed a 5 speed from a 1974 R90/6 in a 1973 R75/5. It was a worthwhile upgrade for that bike.

former Airmarshal, IL.

 
Posted : 04/13/2020 08:55
Victor Doherty
(@vjdeidolon)
Posts: 5
Active Member
Topic starter
 

I forgot to mention that the final drive has a ratio of 3.09. I noticed that the five-speed transmission has a different first gear ratio (steeper) than the standard four-speed. Do you think it will be harder to go from a stop (clutch control wise) with the five-speed? Any disadvantages in using the five-speed? Thanks.

 
Posted : 04/13/2020 12:43
James Strickland
(@8053)
Posts: 423
Reputable Member
 

My un-scientific instinct tell me that you might not even notice the difference. You might compare the difference of the 1st gear ratios and calculate that difference as a percentage to quantify the change you are contemplating. I never gave it a thought when I did the install on my /5.

former Airmarshal, IL.

 
Posted : 04/14/2020 06:47
Bronson Murray
(@bronson-murray)
Posts: 3
Active Member Customer Registered
 

New here.. and not certain this is the right place to ask this question.  

I have a late 73 R75\5 with a smooth case 5 speed that needs a clutch replacement.  Shifts fine but NO free play left.  What clutch do I buy - a \5 or a \6?  The five speed trans was installed in 1984 at 50Kmi with a $50 clutch whatever that includes. The bike has 99,000 mi today.

Thanks

-Bronson Murray

PS. Forgot to mention the receipt states the clutch was used so I suspect it might have came along with the trans.

 

[Mods Added: Please move this post under a subject heading of its own.]

This post was modified 1 month ago 2 times by Richard W
 
Posted : 11/01/2024 17:15

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