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I just rebuilt the top end with a 13:4:1 wiseco high compression piston and rings with all new gaskets and valve seals. It started and ran great but turned it of the last time to put the plastics back on and it wouldn’t start back... checked all the wires, spark, injector and battery.. decided to take the valve cover off and it had jumped time pretty bad, so I Put it back in time and wouldn’t start with good spark, good battery, an good injector... The kfx has a yoshi slip on, procom ecu that was set on map 0 and had 93 gas in it. Everything else is stock. Not sure of the reason it jumped time or what? Please help
 

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Welcome to the Forum...!!!

First off...13.4 piston compression requires 105~110 octane...93 octane is not enough & will cause pre-ignition/detonation to occur & damage your motor...

If the timing jump/was way out & there was piston to valve contact..might be a bent valve...reason for it not starting...!

Can you do a compression test.?

Make sure the valve timing is precise. "29 pins between timing marks" & the cam chain tensioner is retracted & installed correctly......see pictures
 

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Discussion Starter #3
Welcome to the Forum...!!!

First off...13.4 piston compression requires 105~110 octane...93 octane is not enough & will cause pre-ignition/detonation to occur & damage your motor...

If the timing jump/was way out & there was piston to valve contact..might be a bent a valve...reason for it not starting...!

Can you do a compression test.?

Make sure the valve timing is precise. "29 pins between timing marks" & the cam chain tensioner is retracted & installed correctly......see pictures
Thanks for getting back to me, I have not done a compression test yet but that’s next on the list after I pick up some 110 gas. It’s been a struggle finding it local.
 
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