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New top end. Bike shut off and wont start.

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I just put a new top end in my 1999 KTM 250 SX. Changed all fluids, new spark plug, clean air filter etc.

 

My left side of the power valve broke. The gear that turns the power valve broke off but the right side is still in-tact and moves the exhaust valve fine.

 

I started the bike up first kick and it started but ran really bad and had very inconsistent RPM. It ran for about 20 seconds, I tried to keep it running but it just shut off on me and it won't start now.

 

 

My question is. Since the left side of my power-valve is broken, is that what is causing it to run terrible and why it wont start now? I am hoping the piston didn't get screwed up already. Maybe my spark plug fouled since the power valve is not functioning like it should? I just ordered the new power valve gear so I hope that's all it is.

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Some one explain the power valve system to me. I am not even sure if I set it correctly on the right side (The side that actually has the arm that pushes it up and down). I just put the gears in and made sure the arm moved up and down. Is there timing involved? Where should the gear be set at?

 

I don't understand why there's 2 sides of the power valve since the right side has the part that moves the exhaust flap up and down. Why is the left side there? what does it do?

 

 

Just trying to figure this all out because I am afraid I might have actually damaged my brand new top end.

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Some one explain the power valve system to me. I am not even sure if I set it correctly on the right side (The side that actually has the arm that pushes it up and down). I just put the gears in and made sure the arm moved up and down. Is there timing involved? Where should the gear be set at?

I don't understand why there's 2 sides of the power valve since the right side has the part that moves the exhaust flap up and down. Why is the left side there? what does it do?

Just trying to figure this all out because I am afraid I might have actually damaged my brand new top end.

Yes they have to be timed.

I'm not sure you could screw up a top end by incorrectly installing the power valve but I imagine it wouldn't run that well.

Why did you put it back together broken?

You may be able to find a video on YouTube for the correct installation.

I know there is one for my bike on there

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I'm not sure if that's the same as yours but it might help you understand it a little better

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No mine is definitely different then the bikes smaller then the 250. The 250 and up all use a different valve setup.

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Good news! Checked the spark plug and it was fouled. Forget to replace it from before. Started the bike up. Smoked a lot at first. Warmed it up for about 2 minutes and then putted around the neighborhood on the new top end. Bike has boggy power because of the missing power valve. But it runs!!

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