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Discussion Starter · #1 ·
Hello all, i recently had a new piston, rings and valve seals installed in my 03 400ex. They valves are set at factory specs. At idle it sounds great no valve noise at all. Once you start to give it some gas the valves get pretty loud. Any ideas of what my problem is?
 

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Welcome to the forums. Did you check to make sure your rocker arms wouldn't worn any?
 

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Discussion Starter · #3 · (Edited)
No i didnt check that. I had no problems except for black smoke before rebuild. I did exerything properly. There is no smoke now. After installation of new parts the quad wouldnt start. I had to loosen the valves until it would start then adjust by ear for noise. They were pretty quiet. They continued to get louder during a week of riding. I tried adjusting them for 90 mins today with no luck. Like I said in first post there is no noise during idle but just a little gas and they are really loud.

Factory specs wouldnt start quad right after rebuild as I was adjusting them today I set them to factory and have the problem I have now.

Thanks for replying Helmut
 

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I would check to make sure oil is getting to the top of the head. Also, if you've changed the oil and filter recently, make sure the filter isn't backwards blocking the oil flow.
 

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Discussion Starter · #5 ·
I havent changed the filter since. So I dont think that is the problem I can see oil when the valve caps were off. I just remembered something else. Since rebuild I rode around for a week about two tanks of gas. I had to add 1 quart of oil. It was topped off before i started to ride it. It is not leaking anywhere and there is no smoke at all coming from the pipe any idea what is up with that?
Thanks
 

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Sometimes they will use a little oil until the rings seat good, but a quart in 2 tanks of gas seems like a whole lot. If it's using that much, it seems like it would smoke. I don't know what else it could be, though. Maybe someone else will have some ideals.
 

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I'm not trying to be a smart tail but when you installed the cam after the rebuild you did install it with the lobes down and the dash marks alligned with the top of the head with the piston all the way up right? the valves are set at .005 exh. and .004 intake right? if you allign the "T" with the notch in the sight hole on the left side cover if the exhaust valve is tight and the intake is loose you are 180 out rotate around and re-allign the "T" and check the exh again, it should have some play in it.

Also the back smoke was probably nothing more than the carb was too rich. I have seen alot of the choke levers on these carbs get a groove worn into the backside of the lever and they will vibrate the choke butterfly closed causing the engine to produce black smoke and a somwhat loss in power mimicking weak compression.
 

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Discussion Starter · #8 ·
Thanks to everyone that replied. I took her into the shop today they told me that my timing chain was stretched and that i need a new one. He said that I was good to ride it for a couple of weeks the way that it is until he can fit me it.
 
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