Need Some Power Valve Help

C

cwcsrx700

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Jan 5, 2005
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Location
N. East lower MI.
Well I took apart my valves on my 2002 SRX. Found center pulled through and outside ones half through. At the time I was just going to check the adj. on them. I did the under 900 rpm trick to open them then found that. After I seen the center valve I started to take everything apart when I heard the servo motor move. After I put the new valves in does this servo "home" itself or what. I have the copies of the YPVS adj. and cleaning from tech pages. It sounds like I should leave the servo where it moved to and loosen the screw to take the slack out of the cables. Is this all I have to do? Can someone run down this procedure for me exactly, I dont want to ruin the servo or the new valves or anything. Yeah my dealer told me the valves were trouble free and he never heard of this before, claimed he only had to adj. one cable a while back. So I don't have faith in getting his advise. Sorry to be a pain but this is the first time I've torn into the YPVS. Any help would help alot. - THANKS
 

My SRX did the same thing...cable pulled through....very common. As far as adjusting goes, I did the 900 rpm thing and left it where the servo stopped. I took the pipes off and the exhaust manifolds. Stick your fingers inside and the valves should feel "flush" for all three. The hole is on an angle, so when you run your fingers along the top, it should feel smooth. Your valves may be too far in or out by a little bit. All you need to do is adjust the cable at the servo adjuster thingy. You will feel the valve go in or out as you tighten or loosen. This is the most accurate way of valve adjustment imho. Definitely worth taking the manifolds off...plus it's really no big deal since you have the pipes off already.
 
Yeah I didn't mean to have the servo move, when I heard it move I thought holy crap now what. I didn't mark the wheel so I don't know where to start. I just did a search on power valves and didn't see anything like what I did. Still wondering????????? Any more help would be great THANKS!!
 
I also need a little explanation. I did the adjustment per the tech pages and they were OK but still I am not sure if I got the valves set correct. With the valves on a spring, how much free play is too much ? I like the idea of feel inside the cylinder as Pete explained. If I first drop the RPM's and watch the servo move, it will find home when the engine stops. Then the valves should be flush with the cylinder wall inside. Correct ? Will I need to replace the exhaust gaskets after performing this procedure ? Thanks for the help. Pat :rocks:
 
I just did my valves also. Had two pull through at 110cdn. each. ouch! Did the low idle thing shut it down and marked the two servo positions at high and low idle. I don't think it's necessary to pull the pipes but if that makes you feel better go for it. It's impossible to adjust the valve to go beyond the machined step in valve that prevents the valve from contacting the piston. The only real problem to my mind is adjusting with insufficient slack and preventing proper low port operation. I got waxed by my brothers 02 MXZ700 in a roll-on knew something had to be wrong, after replacing the valves the results were reversed so I think the setting works. I cleaned my valves before the season started and had the problem within 500km so frequent cleaning will be part of my routine maintenance now. I'm running Yamalube now, is there a more effective oil that can extend the maintenance interval on the valves?
 
Once the servo finds it's home, then rip everything apart and check the valves by hand to see if it's flush. If not flush, adjust the cables and the valve goes in or out whichever way you need it to go to make it smooth.

No, you don't need to pull the pipes and manifolds...but that is the way I like to do it because then I know for sure everything is adjusted perfectly by feel.

I burn AMSOIL Interceptor oil and it is specially formulated for power valves. I also pour half a can of Seafoam every 3rd tank to keep the valves spotless as a precaution. I then check the valves midway through the season to see how they are making out and they look good. The main thing is maintenance...you need to pay attention to the valves...or else it will cost you races and money to replace cables, valves etc. I don't burn Yamalube anymore because of carbon deposits. I made the mistake once by not paying attention to the valves on 2 of my SRX's. Mine and my wife's machines had cables pull through and at $100 per valve it adds up.

I didn't replace exhaust gaskets....the re-used ones were fine. I added a little gasket sealer (enough to make it tacky) on the black side (not the shiny side). No exhaust leaks whatsoever.
 
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once the servo rotates, mark with a pen or something, my servo rotated about 5 times as i adjusted valve cables, glad i had the mark to rotate it back to by hand.
also, the spec calls for 1/8" gap between the cable housing and valve housing if yo don't want to remove manifolds and feel for flush. use a 1/8" drill bit slide it in the gap to get a flat measurement and dial the cables until the drill bit has a "slip no slop" fit...

that's how i did it.


Ramb
 
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