Straight Pipe on ATV?

John1690

New Member
I want to run a straight pipe (no muffler) on my generic Hi-Bird QH-150ST ATV. Its a 148cc, 9HP, 9.0:1 Compression, 4-Stroke Single Cylinder. CVT, automatic transmission. However, I heard this can damage the engine unless you perform other modifications to the engine (carb jetting?). So, what do I have to do in order to safely run a stright pipe on my ATV for maximum power?

(Please Note: I am not interested in "this will damage your hearing" "this may violate local noise laws, leave this alone", or "dont do stuff you already dont know how to do". I'm not interested in these types of answers. Please stick to a direct answer to my question. Thank you. I just see soo many of these answers in forums I just don't want to see them anymore.)
 
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boogie_4wheel

Guest
You will want to run larger jets in the carb (idle and main) a few sizes higher than stock. Since it is a straight pipe, there really isn't a try #XXX solution. Buy a few different sized jets and for there it is trial and error. GO with a larger and larger jet till you hit peak performance (the best that your butt can tell and there you go.
 
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