4 stroking at high revs

can a air leak cause this at high revs?

i dont know,but you should check your bike for airleaks and seal them with gasket maker.

lightly spray mist carb cleaner around the engine if the idle goes different anywhere than directly at the carb thats an air leak. A better exhaust pipe is what I think makes these motors go better. Along with port matching. Check your plug Its needs to be a chocolate brown or slightly golden . I go for the darker side don not like suprizes. If you are just running a new engine meaning not broke in go 16 to one for break in then 20-24 to one after it takes about 3 to 4 tanks burned before break in You will feel a slite bit more power after break-in.

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Four stroking is caused by an overly rich mixture. Move your needle clip up a notch and it should be better. You could also have too large of a jet.

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If it ain't broke, and you mess with it long enough, it will be.

Good Morning Joe. That Is What I Think Also. When Adjusting Chain Saws, I Run It Full Throttle And Open The High Speed Needle Till It 4 Cycles And Then Turn It In Till It Sounds Rite. That Way You Avoid A Lean Situation. Ron

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I learned the two cycle/four cycle thing from model airplanes.

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If it ain't broke, and you mess with it long enough, it will be.