Lt500 Power Valve

[Zilla529R]

Hey, how much (in degrees) should the powervalve turn when going from idle to full throttle? My powervalve maybe rotates 45 degrees an 8th of a turn, and doenst move until the idle gets really low. So basically the powervalve is in the same position from a high idle to full thottle.

[sblt500r]

sounds like the spring isn't tight enough

[Zilla529R]

Yea, i did not know if I was installing the power valve properly... I just put the engine back together this morning and dont have a repair manual so I took a stab at it. I know the linkage is on properly, but how should I put the spring on?

Thanks

[Chase]

I don't know what your definition of "high idle" is, but the exhaust valve is supposed to close at 4000 RPM and open at 4500 RPM.

[Zilla529R]

I cant really define "high idle" but i would guess somewhere in the range of 500-1000 rpm above a normal idle. The exhaust valve doesnt move at all basically. Does anyone have a picture of the exhaust valve linkage when correctly installed in the engine? I can put a picture up of how the linkage is currently if you would like.

Thanks

[sblt500r]

with the spring and cap on. it should be in line with the 0. then turn the cap 360 degrees counterclockwise. then tighten the 2 screws up. that should be the stock position. was the spring still in good condition? i've seen them all stretched out by somebody turning it to much.

[Zilla529R]

Originally Posted by sblt500r

with the spring and cap on. it should be in line with the 0. then turn the cap 360 degrees counterclockwise. then tighten the 2 screws up. that should be the stock position. was the spring still in good condition? i've seen them all stretched out by somebody turning it to much.

Sorry you lost me. Are we talking about the cap on the left side of the engine? I actually did not take the entire valve apart. All I did was remove the linkage. If there is another spring in the powervalve, besides the one in the linkage, I did not know as the power valve rotates freely.

[sblt500r]

yup on th left side of the cylinder. there is a knob that has 2 numbers around it. 0 and 250 or 500 depends on the year. if you take off those 2 screws there is a spring behind it that knob that puts tension on the valve. if it moves freely then the spring might be screwed up.

[Zilla529R]

Originally Posted by sblt500r

yup on th left side of the cylinder. there is a knob that has 2 numbers around it. 0 and 250 or 500 depends on the year. if you take off those 2 screws there is a spring behind it that knob that puts tension on the valve. if it moves freely then the spring might be screwed up.

Hmm, that would explain why the power valve linkage only moves 45 degres and the quad feels lacking in top end power. Im going to see what I can do tomorrow, if the spring is screwed up badly then I guess its ok to ride it for now.

[sblt500r]

yeah it will still run. on mine the bolt holding the linkage on came off and i was using it for a while till i happened to look and see it missing. i didn.t really even notice a difference. i think the gears noticed the nice hard bolt they were chewing up!!!