Power valve, do I got this right?

gobstoper

Member
Feb 24, 2001
18
0
Specimen; 91 KDX-250. Question; when assembling the valve on the roof of the port, should it be timed so that it rises when the side valves open. The side valves were not removed but were pulled out of time with their respective gears. At this point I pull the actuator rod out and the side valves rotate open. At the same time the roof valve lifts up. I don't see any other way it could be assembled but I could have sworn the roof vavle dropped when the sides opened on my pre tear down inspection.
Any advice would be welcome.

Cap
 

spanky250

Mod Ban
Dec 10, 2000
1,490
1
You have it right, the top raises to make hte exhaust port higher while the side wings open to allow the sub-ports to operate. The thing you need to time right is to make sure both side wings are fully closed and work in unison. It is very easy to get one a tooth off so that it doesn't close fully.
 

bigred455

"LET'S JUST RIDE"
LIFETIME SPONSOR
Sep 12, 2000
782
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Spanky is right,main exhaust is opened fully,the sub exhaust valves should be opened fully when rack is pulled all the way out.Make sure just like spanky said check both sides of the sub valves That they close fully when rack is pushed in all the way.
 

spanky250

Mod Ban
Dec 10, 2000
1,490
1
I have always assumed (uh oh, there's that word:eek: ) it is a slight design flaw, and your bike may not be like this, but when I install my power-valve assembly, the side wings don't quite match each other. I have two choices. If I set them so they both close completely, the wing on the water-pump side doesn't open quite as far as the other side, but if I assemble them so that they both open evenly, the same side doesn't quite close all the way. I decided it was more important to have them both close all the way than it was for them both to open the same amount, so that's how I install them.:cool:
 

gobstoper

Member
Feb 24, 2001
18
0
Hey thanks guys. I'm going to put the new pro lite in mon. and button her up finally. The frames been hanging from the rafters for 2 months now with its new paint fully hardened and waiting for an engine.
Yep spanky I've got the same dillema. One side valve is aprox an 1/8 inch off from the other. You can't make a fine adjustment with the gearing, so closed in unison it is. Hopefully all the crap I cleaned off the center vavle will make a difference. It was moving okay just loaded up enough so that the piston was clearing a path through the edge of it!
Can't wait to go for a ride, miss the little green bomb.
see ya.
 
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