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wiseco piston question?

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The little arrow punched on the top of the piston points toward the exaust,right? I installed a 12.5 to 1 piston last night and when I kick it over it sounds like a valve is hitting the piston on decomp. Any ideas? :cry:

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Yes, arrow does point towards the exhaust.

Pull the spark plug and slowly rotate the crank, to see if you can feel exactly if what and where something is hitting.

you could also try placing a long blade screwdriver on the top of the piston to see if you can feel if the valve is making contact.

your cam timing might be off by a tooth

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NEVER install any piston other than OEM without claying the clearances!I'm sure there will be disagreements on this but I stand by the statement.Remove the valve cover and check the timing and if that checks out take off the head and go through that.You may be feeling nothing,but check it out anyway.

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I love the quote from above. If you have no fear you haven't been fast enough. I must need more top end in my crf450, maybe drop a tooth in the rear :cry:

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