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Old 10-30-2012, 01:29 PM   #42
Airhead Wrangler
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Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,606
Originally Posted by lucky6600 View Post
Comparing to other 980cc engine, how did BMW actually do to detune the engine to make it smoother?
Especially with the same engine block, pistons and 40 mm Bing. Only thing that I could think of would be the more fancy but more restricted exhaust to meet the emission.
The r100r has 32mm bings, not 40s. The pistons are not the same as earlier higher output R100s. They have a lower compression ratio of 8.5:1 compared to 9.5:1 in the higher output motors. The heads also changed from large port/valve in the in earlier models to smaller ports and valves in the later models. The exhaust doesn't do anything to meet emissions. There's no cat. Jetting also got leaner from earlier to later models.
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.
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