SRX question...not hitting R's...powervalves?

SLEDSTART

SLEDSTART

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Joined
Mar 18, 2005
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57
Location
Hampshire, IL
I have a 00 SRX and sometimes when I stab it it hits 8500 and goes like a raped ape. Other times 8 grand is all i get. 3000 miles and I have not cleaned powervalves...so I am going to do that tonight. Any thing else i should look at as well? And is there anythign I need to know about cleaning the powervalves? Never done it but is sounds fairly easy. anything in there I can lose or drop?

By the way...I am runing Goodwins stuff on it and he had it on the dyno when he clutched it so I think the clutching is fine. At least it sure feels great when it does hit 8500 R's.

thanks for any advice...

Snowdog
 
yea i would definately start with cleaning the powervalves, and adjusting them as well. Best way to adjust them is to pull the pipes and manifolds so that you can feel when the bottom of the powervalve is flush with the top of the exhaust port at full open. Make sure you mark the full open position on the servo case and servo wheel so that if you accidentally pull a cable you can turn the servo back to full open position without guess work or having to restart the sled without the pipes.
 
yamaholic22 said:
yea i would definately start with cleaning the powervalves, and adjusting them as well. Best way to adjust them is to pull the pipes and manifolds so that you can feel when the bottom of the powervalve is flush with the top of the exhaust port at full open. Make sure you mark the full open position on the servo case and servo wheel so that if you accidentally pull a cable you can turn the servo back to full open position without guess work or having to restart the sled without the pipes.
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ok I was not anticipating the "adjustment" part. Sounds like it's not rocket science...but I do have a few questions about adjusting them.

I THINK I understand most of what your saying here. But when you say "acidentally pull a cable" are you talking at the valve or at the servo? I have never opened them up so I guess once I open them up I might understand better what your saying. Also "mark the full open position" as in how do I get the valve and servo wide open position? Doesn't the motor have to be running wide open for that...or am I do this mechanically?

Somewhat a novice as far as the knoledge but fairly mechanically inclined. So maybe I will check back here once I yank my pipes and manifolds.

Thanks yamaholic! :yrules:

Snowdog
 
when i refer to pulling a cable, i mean when you are pulling the valves out of the cylinder, if they are stuck at all and you have to pull harder to get them out, it may make the servo rotate from the full open position. Now to get the servo to the full open position, pull the servo cover, and start the sled (with the pipes and everything still on it, this should be the first thing you do). With the sled running, use either the choke or the idle screw to get the engine down below 1000 rpms where the servo automatically goes to full open for the self cleaning/diagnostic mode. Hit the kill switch after the servo stops quivering and stays at full open, and mark the position of the wheel on the servo casing with a white out pen or permanant marker. That is full open, and you can return it to that setting if you accidentally move anything. Hope that helps.
 
ok...well I was to late. I already pulled the valves and cleaned them. They were really gummed up and full of sticky goo when coming out. When I removed the cap for the valve on the last one I was going to clean, I found a broken cable at the spring. This valve was the worst of all of them and I can see why the cable broke. But then again...what I don't get is the cable really doesn't look like it pulls on the valve does it? It looks like the valve just floats in there and the spring tension keeps the valve at a particular position depending on I would assume rpm and/or pressure from the motor?? So why did the cable snap? It broke right where it ends at the collar by the spring. I guess I don't understand how the powervalve works...and what is full open? All the way twards the exhaust (front of motor) or the piston?
So now I have to go pick up a cable. I guess I know why I was hitting 8500 R's all the time. =/
Anyhow, now that I have not marked home on the servo, can I put everthing back together after I get the cable and then set the servo to home position by starting the sled? I noticed the threaded part of the cable by the servo is how it looks like it's adjusted? How the heck do I know where to put those threads when I get the new cable?
Now that I have to tear the servo apart, what do I do to make sure that everything is set proper when I am all finshed?

I had this servo assembly totally apart last year because the case where it mounts to the sled broke on a hard landing. Come to find out you can buy the black cap where the cables are attached to the servo but in order to get the other half of the servo case you have to buy the servo and all....and that was over 200 bucks, so I used the one good bolt hole out of the 2 and used some cable to keep it in place and to prevent it from pivioting. When I put this back together last year I was wondering about the servo and if I had it in "home" position. So I did start the sled with the cap off and it seemed that no matter where I had the servo motor before I started the sled, the electronics returned it to home or open as you call it. I did not know that I had to be under 1000 rpm's though. Do you think I put this thing back together wrong last year and thats what broke the cable? It sure seemed like I had it all back together right after messing with it last year...but again...everytime I dive into something I am learning something.
Damn..... sledding is a lot of work for the enjoyment!

Thanks for your time and if this is to much to explain I can ask at my dealer tomorrow when I go there, But you know how dealers can be sometimes.

I really appreciate your help!!!
Thanks
 
Ok, about the cable breaking, that is pretty common if the valves aren't cleaned enough, or ever. The cables DO pull the valves open, or towards the front of the engine, away from the piston. This opens up the upper part of the exhaust valve, effectively changing the port timing of the engine making it more efficient at higher rpms. The spring in there pushes the valve back to a closed position when the servo/cables stop pulling on the valves to hold them open. If you were hitting 8500 rpm with the cable broken, your rpms will be higher now, so you may need to add weight to the primary clutch weights to keep it from overrevving and wasting horsepower. As for the servo, the home position is what it goes to after you start the sled, which is closed on the valves, but if you get it to idle under 1000 rpms the servo will pull the valves to full open, and if you shut the engine off then and mark the position you can adjust the valves. You adjust the valves by changing the thread position on the tops of the cables up by the servo. The way i like to check the position is to pull the pipes and manifolds and actually feel in the exhaust port so you now when the valves are flush at full open. To pull them up farther out of the exhaust port turn the cable adjustment counterclockwise and vice versa. I think that your cable broke because of the valve being so dirty, not poor assembly. There is quite a bit of excess room the servo can pull the valves without them hitting the top of the valve housing, putting excess stress on the cable. Hopefully you understand most of that. Good luck
 
Yamaholic,
Thanks and yes It's all starting to make sense. Especially after last night tearing them apart.
More problems than I thought. ALL THREE valves were shot due to the cable yanking right out of them. Only the one cable broke. On the other two the nipple on the end of the cable just tore the end of the valve out. Thats why I was thinking the cable did not pull on the valve as I took them apart. Did not know the cable actually seats in the valve.
Sled only has 2800 miles on it and now I know to clean them MUCH MORE OFTEN! I figured somewhere between 2 and 3K I would be fine. WRONG! They were BAD!
Anyhow, 3 valves and one cable ordered and then I can put it back together. Expensive lesson to learn. I am usually pretty good with the maintence (cleaning and maintaining the clutches, pulling and going thru the skid, chaincase etc...) But this was my first powervalve motor so I guess I learned the hard way. Would have been nice if the dealer told me CLEAN THOSE AT LEAST EVERY 1000 MILES when I bought the sled! Not like it's that hard to do.
But I know now...


I think I understand everything you said, but when I get the parts I may post something back up here or PM ya if ya don't mind IF I have any questions. It looks fairly straight forward now that I tore it all apart and I saw what's in there, but the only part I have a litte confusion on might be the servo position. I understand everything you say about getting it under 100 R's etc... but something tells me I might have a question on the positiong. Then again I just might surpise myself...figure it out and quit bothing you...LOL

Thanks a TON Yamaholic. I really appreciate all your time!

Snowdog
 
acnas said:
If you ordered the valves and are waiting for them to come in I would go out and order a power valve tester so you can open them without running the sled. In my opinion it is easier this way.
http://www.maxxperf.com/Pwr_Valve_Test.htm ;)!
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asnas...thanks for the link. I like the idea of making that job eisier. And as far as I am into this anyhow, maybe this will be a nice item to have around. It said "plugs right into the SRX harness" does this mean I can only use this thing on the SRX? Do you have one and how does it tell you where the valves are at?
Maybe I will call Maxximum and chat with them.
 
the tester doesn't tell you where the valves are at, it just opens them to full open position on the servo and holds them there without ever starting the sled. You use a 12V battery for a power supply and it turnsthe servo, pulling the cables and opening the valves.
 
SNOWDOG said:
asnas...thanks for the link. I like the idea of making that job eisier. And as far as I am into this anyhow, maybe this will be a nice item to have around. It said "plugs right into the SRX harness" does this mean I can only use this thing on the SRX? Do you have one and how does it tell you where the valves are at?
Maybe I will call Maxximum and chat with them.
Click to expand...

Works on Vipers as well. Comes with instructions for hook up. When you power up the unit it opens the valves. You need to still take off the exhaust manifold to feel the valves on the port. If they aren't now you can set the cables. I think it is easier because you can power up the valves whenever to recheck without starting the sled. You know they are full open. For $24 to me makes sense. ;)!
 
I have similar problems,You can tig weld the end of the valve and rebuild the end if you have the resource's it worked great for me.I am currently waiting for my test plug to show up at the dealership,I bought this sled as it was so I havent ridden with good valves yet so Im exited for some difference.
 
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