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Old 10-13-2012, 09:26 AM   #18
Airhead Wrangler
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Joined: Mar 2008
Location: Back in Seattle, FINALLY
Oddometer: 6,606
Originally Posted by R100RT Mark View Post
So, for the sake of clarity, and my education, what are the specific differences between U.S. late model 800cc and 1,000cc heads?
From '85 on, I believe it's just combustion chamber diameter. Depth is the same, I think. Valve sizes are the same.

EDIT: I'm a visual person. This is what a section of the two heads superimposed on each other would look like:

Dark grey is the R100 head. Light grey is the cylinder walls. The red is the extra material present on r80 heads. The bore difference is shown to scale. The chamber depth and profiles of the squish band areas are not, but are close enough to show the general differences.
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Airhead Wrangler screwed with this post 10-13-2012 at 10:38 AM
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