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Jeff Policky
Jeff Policky, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 2425
Experience:  Yamaha Gold, Suzuki Gold, Honda Bronze, Polaris Bronze, BRP
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I have a 07 raptor 700 with a 734 big bore kit. Je 11:1

Customer Question

I have a 07 raptor 700 with a 734 big bore kit. Je 11:1 piston I've put new valve seals and rings it has a power commander 3 currently and doesn't run for shit with it hooked up. I noticed that the cam chain tension seems loose with it run in all the way would this cause it to run bad? I'm good with fixing things just fairly stumped valves are all set at TDC and even put a light on it. I think the programmer is the problem. Any suggestions?
Submitted: 1 year ago.
Category: Motorcycle
Expert:  Kenny O. replied 1 year ago.

Hi this is Kenny. have you tried removing the power commander ? Yes it will likely run better once dialed in with the PC, but for right now I would run it with it disconnected. Cam chain tensioner doesn't sound right, did you assemble the top end, was any of the parts machined when you had it apart (surfaces) ?

Expert:  Kenny O. replied 1 year ago.

I'm little concerned about your tensioner, when you say its "tension seems loose" if you can give me a little better description on that as to why you feel there is an issue there ?

Reason I asked if any of the surfaces were surfaced is depending on how they big bore was done they might have surfaced the cylinder or even the head surface and that could be contributing to your tensioner issue. The tensioner on this model is your basic cam chain tensioner design that is used widely not only on this engine model but others.

So that brings me to cam timing, can you give me a compression measurement ?