Powervalve slaming exhaust port

NO HAND

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#1
I noticed on the last rebuilt that the powervalve flaps are hanging lower than they should in the closed position. It is so far low that the flaps are gouging in the floor of the exhaust port, just behind the bridge. Also when the pv is closed, there is a gap between the upper edge of the exhaust port and the upper edge of the powervalve flaps, so much it is hanging too low. Once in the open position, it goes where it is supposed to and works fine. I rechecked everything to make sure it is properly assembled. What is causing that? Could I use a round spacer on the stop pin on the side to reduce the travel in the closed position?
Thanks!
 

marcusgunby

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#2
Yes you need to get a pin to reduce the travel of the valves-It needs to have a OD of 7mm(which is bigger than std) that will give better bottom end power.
 

EricGorr

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#4
Have you got a KX? The exhaust valve pocket in the cylinder tends to wear out making the valves a bit loose and droopy in the closed position. There isn't a heck of a lot you can do when they get like that.
Good luck:)
 

NO HAND

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#5
It's a 2000 CR125. I'm the only one around here with a honda so I don't know if it's a common problem.