G
gone_fishin
Guest
i know this is a techie question, but it's inspired by a legal issue.
briefly (please correct or expand): "displacement" is about the working volume, no? well, on 4-stroke engines the entire stroke is technically the factor when determining displacement. on my "70cc" engine, the "compression" stroke doesn't start until the piston fully covers the highest port (exhaust)...the top edge of the exhaust port is 28mm from the top of the stroke.
47mm bore X 28mm stroke...you're not gonna believe what that comes out to...48.6cc
is there some set of standards (technical or legal) set to paper somewhere that would clear this up for me?
somebody set me straight, because my next engine will be legally under the limit whether i like it or not.
briefly (please correct or expand): "displacement" is about the working volume, no? well, on 4-stroke engines the entire stroke is technically the factor when determining displacement. on my "70cc" engine, the "compression" stroke doesn't start until the piston fully covers the highest port (exhaust)...the top edge of the exhaust port is 28mm from the top of the stroke.
47mm bore X 28mm stroke...you're not gonna believe what that comes out to...48.6cc
is there some set of standards (technical or legal) set to paper somewhere that would clear this up for me?
somebody set me straight, because my next engine will be legally under the limit whether i like it or not.