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Discussion Starter #1
Hello all, I have an 01 ZR 800 with APV. Last week I removed the power valves for cleaning and found that both cables were disconnected from the servo motor. After cleaning the valves and reconnecting the cables I wanted to test to make sure they were working. With the sled elevated on a stand I started the sled and ran the RPM's to about 7000, and the valves wouldn't open. It seemed that the sled didn't want to rev much beyond 7000 I'm assuming due to the fact that the valves aren't opening. I then removed the servo motor, and was able to get the servo to rotate on the bench. Does anyone have any recommendations on further diagnostics? I can't seem to find a schematic on the servo's electrical.

I did the same test after cleaning the valves on my wife's ZL 600, and the valves would open at about 7000 RPM every time.

Thanks,

Darrick
 

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With the servo on the sled, will it cycle at all when you first start it? It should cycle one time if all is well and three times if there is a problem. If it does not cycle at all then check incoming wires for voltage. There are some electrical gurus on here that can help you if you don't have juice going to the servo. Ron.
 

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Discussion Starter #3
I had someone look for the servo to cycle, and it seemed to move a very small amount twice. I don't think it moved more than an eighth of an inch though. On start ups since I haven't seen any movement at all.
 

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Again with the servo on the sled, remove the cables and start it again and check to see if it cycles. Maybe it is to weak to pull the vavles. Pull the cables by hand and make sure the valves are opening and returning with no resistance other then the return springs. Ron.
 

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Discussion Starter #5
With the servo back in the sled with the cables disconnected I still have no movement. I can pull the valves open by hand without a problem, and they retract just fine as well.
 

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Well then its all about the electrical end of it. Maybe Kev or C-note or Auggie or Arctickelly can help you out with that end of it. My knowledge of wiring and such is best left to the guys that KNOW. Sorry. Ron.
 

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Discussion Starter #7
So after lots of testing and troubleshooting I finally nailed down my APV issue. I thought I would provide an update in case any others run into the same problem.

Not sure why I didn't think of this earlier, but I removed the servo motor from my wife's sled and replaced it with mine. The servo functioned perfectly. I then reinstalled my servo motor back into my sled and adjusted the cable lengths as they were a bit short. I started the sled and still had no servo cycle on startup. I decided to give a small amount of throttle, and the servo cycled once. I reinstalled the cables, and tested again with the sled on the lift, and the valves opened and closed perfectly.

When I described the problem in my first post the servo was moving a very small amount. I think this was due to the cable lengths being out of adjustment. Subsequent tries to get the servo to cycle failed because the RPM was to low.

Thanks again to those that provided valuable troubleshooting information.

Darrick
 

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Make sure you check the muffler. They are pron to braking internally. Remove the muffler and shake it. Also look up the exhaust outlet for two holes in the outlet pipe and make sure they show no signs of cracking.

Auggie
 

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Discussion Starter #9
Just removed the muffler, and checked the outlet pipes. Both seem fine with no signs of cracking. I did however have a small piece of perforated metal floating around on the inlet side that I removed. Now no rattling at all.
 
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