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Discussion Starter #1
My 02 660 grizzly with 1300 miles will start and idle like new, as soon as I try to move it, the engine backfires so hard it blows the carb off of the engine, thank God for the throttle and choke cables, otherwise I'd be chasing the carb across the street all the time. What makes me feel like lean run, is that I can't really flood it out with the choke, It will run bad but not die. I can turn on the gas with the bowl off the carb and gas pours out from the needle and seat. If you put your hand over the intake and hit the starter it feels like it's going to suck your hand into the cylinder. Here what we've done: fresh gas, rebuilt carb, installed bigger jets, installed carb off another perfect running machine(I own 2), new plug, new coil, new plug cap(cracked $45!!), leak down test, adjusted valves, compression test(127psi), checked carb mount boot, 23kv at the plug while cranking. What am I missing, I would really like to ride this rather than look at it.
 

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Have you checked timing? Stretched timing chain or sheared flywheel woodruff key?
 

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I would do the pencil down the spark plug hole trick to find T.D.C. while looking at the time marks. and as the carb is off and probably the gas tank, watch the valves move over the top as the piston crosses the top.
 

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Discussion Starter #4
Ok, with cam timing, I pulled both inspection plugs, but when I was at tdc, I didn't see marks in the cam hole, even at 180° out. Don't I have to pull off the valve cover to check for 2 alignment marks to be horizontal with edge of head?
 

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Did you remove the plug screw behind the pull starter?
I don't know of marks under the valve cover, but if the piston is at t.d.c. and the marks do not show the w. key may be sheared. That's why I use a pencil for t.d.c. and look to see if the valves are closed. No marks to be seen is a problem I have not experienced. They should be there somewhere.
 

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Discussion Starter #6
Pulled the plug and did the tdc thing with a dial indicator, the flywheel marks lined up perfectly through the inspection hole, going to pull the rocker cover of today to check cam timing.
 

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You could pull the valvecover off and check the cam timing marks, how's your chain tensioner? I wonder if you've stretched a timing chain. You'll have to remove the tensioner anyway to pull the valvecover, I'd start there
 

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Discussion Starter #8
Cam was a tooth off, removed the adjuster and the chain was still to tight to adjust without removing cam, how could that have happened?
 

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The only ways I can think of to jump a tooth would be a stretched timing chain or a faulty tensioner. I would just replace them and the oil pump chain, they're not too expensive.
 

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Cam was a tooth off, removed the adjuster and the chain was still to tight to adjust without removing cam, how could that have happened?
When everything is rotating, there is loads exerted that you can't replicate with your fingers, etc.
Things will happen that you will wonder how?

Replace the chain and tensioner and ride on. I would also replace the oil pump chain just like steampunk mentioned. It is recommended that you replace both at the same time. This is because they both wear and stretch, and if the timing chain is stretched to it's limit, I can almost guarantee the oil pump chain is in the same condition.
 
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