View Single Post
Old 10-12-2012, 06:44 AM   #4
Airhead Wrangler
Adios Mexico
Airhead Wrangler's Avatar
Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,577
Originally Posted by .fisher View Post
Port-sizes are where my knowledge drops off significantly. So do the post 90's R100's have the 40mm ports? Are these what people put the larger European Bing's that I've read about here and there?
The large port (and valve) heads were used up until '83 or '84 on US models I believe. The general consensus is that the smaller port heads work better in just about every case. Even if you want to put bigger intake valves in, the small port heads work better.

Originally Posted by .fisher View Post
The main reason I've jumped to this is that my local BMW scrap heap (Repsycle) had a few nicely priced R100 short blocks on my last visit. I just want to be sure I'm not taking 2 steps forward and 1 backwards and mostly that it's a good solution.

Do you have any knowledge on how easily the R80 trans would mate to the R100 block? I'd love to have that extra power you (and many others) feel is missing off the bat, using BMW parts.
No prob whatsoever. The blocks are identical as far as how the trans fits up. There may be a some minor differences in the blocks depending on the years, but nothing that will affect fitting it in your frame or mating your trans to it.
R80ST Gets The HPN Treatment
Seattle to TDF on an airhead

Current rides: HPN #834, '93 R100GSPD "red rocket", '73 R75/5 Toaster mongrel, '80 Ducati Pantah 500SL, '92 DR350, '67 Honda SS50, '80 Honda Chaly.
Airhead Wrangler is offline   Reply With Quote