Thread: My Yamaha SR250
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Old 07-28-2018, 11:32 AM   #14 (permalink)
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One option to improve the efficiency of the gas engine would be to increase the compression ratio to say 10.5:1 by planing the head, and porting intake and exhaust passages. Depending on the fuel available alcohol injection or some other means to reduce pre-ignition might be needed. A local machine shop could do this without pulling the engine.

Last edited by Grant-53; 07-28-2018 at 12:09 PM..
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