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Bike still won't start - bent valves?

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After rebuilding my bike sometime ago I have been having a hell of a time getting the bike the run. It did run a little while once but was a bear to start. I have tried a variety of different things, cleaning carb, checking valve clearances, cam timing is spot on, strong spark, etc. I pulled the air filter and fired a good shot of either into the carb, the engine didn't even try to start. I am starting to think now that maybe I bent my valves immediately after the rebuild. The timing chain had slipped off the bottom sprocket and I am thinking that perhaps during the first start attempt there may have been some contact between the piston and the valves. I am guessing that bent valves could explain why the bike won't fire at all. Is there an obvious way to check for bent valves other than pulling them completely out of the head??

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Check the valve clearance,if you have bent the valves the clearance will be different than what you set the first time.You did set the valve clearance didn't you?cheers

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get the engine on tdc,screw a compression gauge hose into the spark plug hole and plug a air hose on to it. now listen you should not hear any air. if you can hear air out the muffler = exhaust valve/seat air box=intake valve/seat oil fill hole=rings/cylinder

hope this helps :thumbsup:

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Decompressor clearance in spec. The cam came on and off some many times and don't recall what shims I used initally. Valves are currently in spec. I guess I will have to get a screw in compression tester. The one I have won't reach down to the spark plug hole. Any recomendations?

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take the head off the motor and fill the ports with a liquid (water will work) and if they seap they are bent. another way is to go in a dark room with a L.E.D. light and put it in the port and look at the valves and if u see light coming through that means u have bent valve also either way will work and they are a for sure method

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Just a regular old Kragen, Autozone, checker auto, Pepboys or whatever youve got handy out your way will probably have the compression gauge with the rubber hose attached/ment that will work. I think I paid 20 bucks for the one I got. It uses a hose with the fitting on the end and the other end of the hose has a regular air hose quick disconnect on it so you can fab up any kind of a adapter you need. You may be able to borrow one from an autoparts store too. Pull the spark plug and take it with so you know what you need to screw into. You may end up needing to buy a shouldered bolt and drilling it and cutting the head off to make a fitting for the head.

If its way off in compression you need to pull the head again anyway. Did you ever check the throttle plate?

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I checked the throttle plate last weekend, it was correct as far as I could tell.

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