AKheathen Posted April 1, 2009 Report Posted April 1, 2009 hey, i can't remember how wide you can safely go with the exhaust port without wearing the rings down too fast. i think i remembered like 70 degrees, but not too sure. it's only for a little 50cc, but i have to port the exhaust a bit so i can build a pipe that will fit. Quote
mopar1rules Posted April 1, 2009 Report Posted April 1, 2009 70 degrees?? i think you mean 70% of bore diameter. my graham bell book says up to 73% can be used. my snowmobiles main exhaust port is 73% of bore diameter. ex, if your cylinder bore is 1.530", and you want the exhaust port width to be 70% of the cylinder bore diameter, then the port width will = 1.071" 1.53" X .7 = 1.071" Quote
2003LimitedBanshee Posted April 1, 2009 Report Posted April 1, 2009 70 degrees?? i think you mean 70% of bore diameter. my graham bell book says up to 73% can be used. my snowmobiles main exhaust port is 73% of bore diameter. ex, if your cylinder bore is 1.530", and you want the exhaust port width to be 70% of the cylinder bore diameter, then the port width will = 1.071" 1.53" X .7 = 1.071" what he said. Bore:exhaust width ratio not typically to exceed 70-72%. More than that and the ring will beginning deflecting into the port too much. Quote
AKheathen Posted April 1, 2009 Author Report Posted April 1, 2009 ok, thanx guys. that's what i was looking for :thumbsup: just couldn't remember :shoothead: Quote
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