Power valve screw broke.

I have a 1999 ktm 250 sx that I was re-doing the top end on. This bike apparently has two power valves, one on each side of the cylinder. The power valve that is on the left is broken. There's two little gear things, one is a circular gear and the other is a wedged shaped gear. The circular gear that rotates the valve up and down has broken off. It looks like it is able to be unscrewed and screwed in again. Kind of like a bolt with a broken head.

 

 

How would I go about fixing this and getting the screw part out? Do you think I could JB weld it back on?

 

Also, since 1/2 of my power valves are working, how does that effect the performance? Before my top end went, I had a boggy throttle response, wouldn't rev high in neutral. It also lacked a power band in 1st and 2nd gear but had power in the higher gears.

Edited by ChrisGG

I have a 1999 ktm 250 sx that I was re-doing the top end on. This bike apparently has two power valves, one on each side of the cylinder. The power valve that is on the left is broken. There's two little gear things, one is a circular gear and the other is a wedged shaped gear. The circular gear that rotates the valve up and down has broken off. It looks like it is able to be unscrewed and screwed in again. Kind of like a bolt with a broken head.

 

 

How would I go about fixing this and getting the screw part out? Do you think I could JB weld it back on?

 

Also, since 1/2 of my power valves are working, how does that effect the performance? Before my top end went, I had a boggy throttle response, wouldn't rev high in neutral. It also lacked a power band in 1st and 2nd gear but had power in the higher gears.

 

Could you post a pic of what you have broken?

 

My KTM (could be different) has a ring/lever/rack/gear that is moved by the arm out of the crank case, which turns three rollers.

 

Left gear controls the 'left roller" middle gear port height main power valve flap thingy, right gear the 'right roller'

 

If any one of these do not function as designed you are going to have soggy power, and 'lack a power band'

 

Mark

Here's the broken valve gear. 2mzkux3.jpg

That is very different to mine.

 

Is that shaft where the gear broke "slide in"?

 

If so, simply remove screws and plate and order another online or at the LocalBikeShop.

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