Vintage BMW Motorcycle Owners

Hey..I’m wondering…. will a R100/7 fuel tank fit on a 1976 R90/6 ? I’m wondering about the brake master cylinder on the /6 fitting under the /7 tank. Thanks.

I think the primary issue going to be the seat-tank combination. The /6 seats are relatively long while the /7 tank is also long. That means there will be conflict. If you put a /7 seat on a /6 bike, there will be a gap between the seat and tank.

What Kurt says.

Also, I am not sure but tanks made after 85 may not have the indent for the Master cylinder. My 84 still does because instead of the master cylinder, there is the ignition module in place of where the under tank MC used to be on the older bikes. So gas tanks up to 84 might fit. Make sense? LOL, St.

Thanks. The plan is to install a /7 seat and tank onto a ‘76 /6 frame..so the seat/tank GAP might not be an issue. The shape under a /7 tank looks similar to a /6…but not exactly the same. Fingers crossed that the M/C fits.

….and the answer is: YES. A /7 tank does fit on a R90/6.
Now, on to the seat puzzle solution. The /7 tank is longer than a /6 so, just as Kurt Schrader says, the /6 seat is too long with a /7 tank. I’m hoping a /5 SWB seat will fit.
So if anyone has a SWB /5 seat in very good condition on their shelf, please pm me. If that doesn’t work, I guess I’ll look for a /7 “S” type.
Thanks.

Check with Sibenrock, Boxer two valve or Flat Racer, they may have a new /5 aftermarket but good quality seat in stock. St.