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1974 Ty250 Engine Mods

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I have a 1974 yamaha ty250 . Does anyone know of anything to make it more snappy and powerful..It's on it's 2 nd overbore. I already has boysen reeds and a reed spacer .I also added a Sammy Miller silencer.It is already pretty good ,But i rode a ty at a trials and was amazed.in the difference in mine and the other one.The owner said he bought it that way. Anything will help Thanks :thumbup:

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More snappy: lighten the flywheel

More powerful: source a later model cylinder and head. The TY250B (1975 model 434), C and D model (493 model) TY250s are noticably more powerful than the TY250 (1974 model 434) in standard trim.

More powerful: Big bore it to 320cc (DT360 piston, new sleeve, welding and machining). Not cheap but works

More powerful: fit an ignition that has an advance curve

More powerful: raise the compression ratio

More powerful: fit an expansion chamber

Talk to Bob Ginder at B&J Racing

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I have a stock ty250 with the exception of a Kehin pe 28 mm carburetor,rides like a modern bike!!!!If you want to find out more about jetting for it send me a e-mail

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