Tell me about powervalves please!

N

nick5oh

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Joined
Mar 10, 2015
Messages
359
Location
Hunstville, Ontario
So I've been trying to figure out my sled (99 SRX) issues for quite some time now. Clutches were all outta wack when I got it. Slowly got em all worked out. Also did other minor maintenance and such. Still having an issue of lack of acceleration and mph after shifting out. Sled will rev up to 8300-8400 at the hit of the throttle wide open, hang for a second or two, shift down to around 6000-6500 (hard to tell was on a trail gotta be safe lol), and then basically no power, almost like a bog, more like maxing out 2nd gear in a stick car and then shifting 5th lol! It is super slow to climb rpm and mph. Here goes the list of things I've done:

All stock 99 primary and secondary clutching. YWY primary spring, 8DN-10 weights with 13.3 base and 17.2 tip rivets, stock 15mm rollers, red secondary spring wrapped at 70 with a stock helix, belt height set at 1.5mm above secondary sheaves.

M10 rear skid in it when I bought it. I put all new idler wheel bearings, new slides, track tension set to creep slightly when "helped" by lightly pressing with a finger.

New plugs and new plug caps, cleaned carbs, cleaned powervalves.

HOWEVER! one thing I have not done yet is adjust the powervalves. I have a feeling it may be the issue that I'm chasing.

What I want to know is when do the pv's come into action? If they are not adjusted correctly what happens?
No power?

I did notice that while diagnosing an idle issue that when the rpm got around 900 ish the servo motor was twitching and tweaking? Seemed like opening and closing back and forth. Don't know if it's normal.

Basically what I'm wanting to know is the function of powervalves and the symptoms of last of adjustment or maintenance.

Desperately trying to sort of my sled. Thanks guys.
 

If the servo is twitching the valves might be too tight. Also while you have the servo cover off check to see if you can pull on the cables. You could have a pull through not allowing the power valve to open. Valves are for low end to mid. At wot they are fully open. If they don't open it will effect your top RPM's.
 
RB2001SRX700 said:
If the servo is twitching the valves might be too tight. Also while you have the servo cover off check to see if you can pull on the cables. You could have a pull through not allowing the power valve to open. Valves are for low end to mid. At wot they are fully open. If they don't open it will effect your top RPM's.
Click to expand...

So my cable adjustment may be too tight I guess. But if they are for low to mid end rpm range and I don't have a pull through stopping them from opening they are most likely not my issue I guess. I do not have a pull through I know that for sure. Out of adjustment maybe, have to check still.
 
The valves open at a certain rpm. I can't remember exactly what rpm but I know for sure if they aren't opening it will not hold rpm. When I first got my srx the valves were upside down and it revved to about 8400 then bogged to about 77-7800. Inspect the valve for pull throughs and check the cables and make sure they move freely. Then go to tech section and check out the write up on adjusting them. Getting them right will pay off big. Tons of power can be lost if they aren't working right.
 
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