adjusted power valves

When I adjusted my power valves the servo sets itself open as described in the tech pages. But when the servo turns it goes a little farther forward then backs up a hair and then stops. So that's where I hit he kill switch and marked it it didn;t move but I'm wondering if I possibly adjusted it to tight, if it can go a little farther forward. Any comments? Haven't rode it yet since it was adjusted, but the number 2 and 3 cylinders were way out of adjustment. I mean i had to almost use up all the cable lengthy. So I think it's time for new cables.

Any thoughts would be great.. Thanks

I bet you have #2#3 powervalves pulled through if you needed to adjust them all the way out!

Start it up with the servo cover off. Then use the choke to get it ideled down or stall. The pulley should turn counterclockwise. Thats where you set them.

no pull throughs just went through and cleaned everything and put new oil seals iun and o rings and cables look good on all ends

I make sure my cables are good and slack, then idle down so the servo opens fully and then adjust. It is possible that the cables are too tight and pulling the servo motor back some.

Yeah I know how to idle it down. My question is, is it normal for the pulley to rotate back clockwise a 1/16 before it rests in the full open position. I just don't want to over adjust them.. Wish i could show a video of what I mean.

im going to go with yes i think mine did the same thing last time it just turns back the "littlest bit"

mattyg1405 said:

im going to go with yes i think mine did the same thing last time it just turns back the "littlest bit"

Click to expand...

Yes they do..

powerssrx700 said:

When I adjusted my power valves the servo sets itself open as described in the tech pages. But when the servo turns it goes a little farther forward then backs up a hair and then stops. So that's where I hit he kill switch and marked it it didn;t move but I'm wondering if I possibly adjusted it to tight, if it can go a little farther forward. Any comments? Haven't rode it yet since it was adjusted, but the number 2 and 3 cylinders were way out of adjustment. I mean i had to almost use up all the cable lengthy. So I think it's time for new cables.

Click to expand...

I didn't pay much attention to this post until adjusting mine this year and after playing around some more, the above condition could explain fantom pull throughs after adjustment.

After installing my clean valves this year I applied voltage to the test plug to open my valves and noticed the servo wheel go open than turn back slightly (as discribed above) and wasn't lined up with my mark from previous adjustments.

Having never noticed this before I saw that the cable adjusters where near the max out positionso I screwed them in nearly all the way (maximum cable slack), twisted the servo wheel to the closed position and reapplied voltage to the test plug and did NOT see the servo wheel turn back slightly from the valve open position and found it did line up with my mark.

I turned the adjusters back out and sure enough the servo wheel went open and than back slightly and again missed the marking.

It appears that if the servo runs up against a valve that hasn't enough slack it'll turn back to eleviate tension on the cable (at least in a static condition). This might explain why some see pull throughs even though it is thought that the valves have been adjusted.

Anyhow, I'd recommend that when assembling the cables to the servo housing that one turns the adjusters all the way in (maximum slack) before energizing the servo to it's open position and making final adjustments.

I'm not sure if this would account for pulled through powervalves. You set them at minimum 2,5mm slack. So even if it pulls 1 mm further, you should have still 1,5mm left. What am I missing here?

Here are my thoughts on this issue.
It's critical that the PV wires are in the correct order:

a) the PV wires are in correct order VERTICALLY between the valves and the motor.

b) the wires are in correct order at the servo house mounting.

c) that the wires are in correct order on the pulley "wheel".

Get any of these things wrong, and you will not have the correct length, the motor could pull the wire further than you think it is going to do.

Now, how do you get them in the correct order?
Get a shop manual!

norwegian said:

I'm not sure if this would account for pulled through powervalves. You set them at minimum 2,5mm slack. So even if it pulls 1 mm further, you should have still 1,5mm left. What am I missing here?

Click to expand...

I didn't measure the amount the wheel turned back nor how much that translates to valve movement but I suspect it's beyond the +/- of the spec.

You may be right. But if the valves are adjusted to the less than open mark, directionally the slack would be reduced in operation. How much, I don't know.

My main point is that on my '01 SRX the servo wheel should not turn back and if it does the cable adjusters are preliminarally set too tight. And if I were to adjust the cables with the servo wheel turned slightly back, they'd be out of adjustment... erroring towards not enough slack vs. too much.


Bottom line - if when energizing the servo to the valve open position the servo wheel turns back slightly, loosen the cable adjusters and re-energize the servo to ensure the servo wheel is really in the full open position.

Food for thought.

Look at my post above I edited it.

if you keeping dropping the idle until it almost dies,the servo should finally stay locked in full open position.Tried it the other day,mine was still bouncing back,turned idle screws more lower setting and finally got the servo to stop in full open position.Then shut the engine off and mark the servo position with a marker for future reference..simple as that.

For some clarity - The OP's question was - should the servo wheel turn back from what first appears to be fully open - and from I found on my sled, the answer is definately NO. And if it does you run the risk of making the adjustment from a not fully open wheel setting.

Whether you turn the servo wheel with the test plug per the shop manual or go off the reservation and idle the sled down, the servo wheel should go open and NOT turn back slightly. If you adjust from this slightly turned back position, you run the risk of a pull through or more specifically your mis-adjustment puts you closer to no slack in the cable/pull through.

Many here have been told to remove the cable from the servo housing when cleaning (not mentioned in the manual). Well, if you put the cables back onto the housing and don't turn the adjusters all the way slack, when it comes time to perform the first step in adjustment (energizing the servo open) and the adjusters are not in the slack position, you're starting your adjustment from a less than fully open wheel position.

Or, if you are just adjusting and not cleaning and one of your cables is already too tight, energizing the servo isn't getting you to the fully open position.

A tell tail sign would be a slight turning back of the servo wheel when energized. If you see this, loosen the cable adjusters and re-energize the servo.

I didn't mention proper routing of the cables at the servo housing/wheel slot/cable holder bracket since this is a given.

This much I can tell you, setting the servo with the engine below 900 rpm is an important step in the process, if you are doing this without the test wire method. With the engine in the normal idle speed the servo is not even close to the needed position. When I do them, I actually turn the idle screw down and get it to idle in the 850 or less range(yes, it should idle down this far). The servo will move counter-clockwise considerably at the lower rpm.
Just to try to make this easy to understand, if the hand on a clock points at the 12 at 1800 rpm, then the hand will point roughly at the 10 at 850 rpm. This is where I believe that a lot of people make the cables too tight on the adjustment, and get pull-thru. You must do this step properly before beginning the adjustment.
By setting it at 2.5 MM, setting it with the servo in the correct position, you should not have issues. Take your time and follow the steps.