• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

Advice on a '76 R75/6 with '78 R100RS motor & gearbox

scx867

New member
Hello

I'm considering the purchase of a '76 R75/6 that has a '78 R100RS motor & gearbox fitted. The seller has completed a very thorough paint and mechanical overhaul of the bike's engine, gearbox, wheel bearings etc, including upgrade to brakes (2 x cast iron PFM brake discs as per '74 R90S + handlebar mounted brake reservoir) to provide greater security vs the greater engine power. I am informed (though stand to be corrected) the "6" frame has the identical dimensions to fit the transplant of an R100RS motor/gearbox.

I'm not concerned about the mix and match of components and would use it as a weekly ride, though would very much welcome any feedback/ observations on such a bike, more so if you completed such a "transplant" or have ridden a similar example.

cheers
Patrick
 
Hello Patrick,
If the conversion is well done and the drivetrain, starting at the engine ending at the rear wheel are in good condition, I wouldn't be turned off by it. A stock bike doesn't have the issues that a modified may have, but that's part of modifying or having a modified one: working out the details. If you choose to pursue it, enjoy your project and be sure to share photos. Take care, stay well and ride easy.
gp
 
Not sure if they began adding it by 1976, but the /7 frame had a few additional strengthening elements mainly around the front down tube. But not enough to be that big of a deal.
 
I thought I was doing a web search. The /6’ series was a transitional series from the smaller /5’s to the larger and more powerful /7series. Example the ‘74 and ‘75 had 14mm diam. front axle the ‘76 got the 17mm diam. front axle. The frame got some substantial frame bracing. The engine block was also modified for ‘76. 1000cc jugs and pistons could be installed without boring the cases. I’ve always liked the looks of the /6 with it’s more old school rounded body work. I’ve been procuring parts for a 70hp /6 build. 40mm carbs, 336 performance cam, 1000cc pistons, big valve heads, twin disc brake front end, etc.. Old school look with some muscle under the hood. Kind of a sleeper. Just something I’ve always wanted. Leo Goff is s assisting me in this build. Don’t get no better than that. Just gotta find the donor bike.:thumb
 
Back
Top