holding pv servo open to test

fourbarrel

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St George,New Brunswick,Canada
What's the best way to hold the servo open in the right position to make sure the servo is operating properly? I still have a weird issue with my '98 running a 300 watt ignition and am trying to rule things out one at a time.It starts fine and idles perfect,low end is great with lots of snap but once I get into the throttle and the revs get up to around 7000 it seems to hit a ceiling and stutter.I wish I had a way to take a video clip to help show what's going on.Tonight I tried a different set of clutches to rule them out because I thought in the back of my mind it may have been one binding at a certain spot when it opens but no.I figured if I can get the servo locked open and see if it does it with the valves opened all the way I can rue that out one way or the other.If that doesn't work then I may try replacing coils to see if one of the sparkplug coils are breaking down at high revs.
Anyway long story longer what is the best way to hold the servo open? Vise grips? And I assume it would be best to unplug it to when testing it this way?
 

you can pull the cover off, start the sled, turn the idle down till the sled stalls. just before stalling the rpms should get low enough that the servo will open. This is how you can adjust the valves without the plug or battery. then just unplug it and go for a ride. To my knowledge, there is only a code that is set but no timing change.
This is a thing I always ask, and sorry if it sounds dumb. have you checked that the valves are in the correct position. Many times, the complaint your making results in upside down valves.
 
Oh things are rolling along lol, picked up a '19 SRX to add to the stable but haven't had much chance to ride it yet. I think I have a grand total of about 2 miles on it just from riding around a mowed field.
This sled has had this issue ever since I converted it over to the 300 watt mag. I got the flywheel from you for it actually. I've had the powervalves out and back in,adjusted probably 7 or 8 times but still can't figure out what the problem is. I was wondering if the servo would stay open if I unplugged it when it was open. I have a service cable to open it with a battery, I may just try that tonight. It's forecasting rain and 4 or 5 degrees above freezing for Saturday so whatever testing I'm going to so will be the next couple of evenings.


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Very interesting question. I have similar problem. I'm thinking i have an electrical short to servo motor. I switched servo motors and no luck. Sometimes the sled pulls RPM. The next pull it doesn't. I've searched the harness and cannot find a short. I'm gunna try that idea and rotate the servo barrel by hand to pull up the valves and mark the 12 o'clock position. Then make several test passes on the ice and see if I can pull RPM to confirm my problem is power valve related. Also check to see if the barrel stays at 12 o'clock.
Thank you for the test idea.
 
I will be up to see you soon Joe. The power valve tester isn't needed just yet and i know its hanging in your garage. I need to confirm that the valves are my problem as discussed above. Last winter you were out on the ice when i couldn't pull RPM on and off. i will be up real soon for a test and tune date on the lake. Also just about ready to run the new secret weapon.





 
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