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Discussion Starter · #1 ·
I have got an 02 ZR600EFICC that I am getting a ‘surging’ going on between say 6100 to 7000 rpms when just cruising down the trail. It almost is like a governor, you can feel the sled pull and let up, pull and let up. I do not see the tach go up and down much at all. When opened wide open it seems to run pretty true. Compression is good 125+ both sides. No ECU codes.

Leading me to the servo. It seems to be functioning properly, cables adjusted, valves are clean. With the back of the sled up and you open it up above 7000 the servo trips. Now it does not ‘stay’ open if I remember right, I believe it opens and closes right away-is this correct?? And then when it idles down it trips. The dealer said this was OK. ???

Do you have any other ideas?
 

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<div class='quotetop'>QUOTE (geeman @ Jan 5 2007, 04:37 PM) <{POST_SNAPBACK}></div>
I have got an 02 ZR600EFICC that I am getting a ‘surging’ going on between say 6100 to 7000 rpms when just cruising down the trail. It almost is like a governor, you can feel the sled pull and let up, pull and let up. I do not see the tach go up and down much at all. When opened wide open it seems to run pretty true. Compression is good 125+ both sides. No ECU codes.

Leading me to the servo. It seems to be functioning properly, cables adjusted, valves are clean. With the back of the sled up and you open it up above 7000 the servo trips. Now it does not ‘stay’ open if I remember right, I believe it opens and closes right away-is this correct?? And then when it idles down it trips. The dealer said this was OK. ???

Do you have any other ideas?[/b]

Should stay open until RPM's get below 6700 ish, how many revs are you able to pull? should be 8000 to 8200 if running correctly and clutched right.
 

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Discussion Starter · #3 ·
I went out and double checked tonight. It will open and close once early about 6200, then if gradual up to 64-6500 it will open and the engine will faulter a little and close, and do the same thing on up till about 7-7200 when it opens up and stays open. Sort of wants to miss a little too.

Does this sound like a stator or a servo going bad and taking too much juice causing the engine to faulter (I don'e even want to mention CPU!!)
 

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Discussion Starter · #5 ·
Cables are measured and adjusted properly with the exposed cable only. Connections looked good, clean with no corrosion. I could check the voltage at an accessory terminal(br & yel) looking for I assume 12 to 14 volts??

Would a faulty servo do this? Like I had said when the valve does open at 64-6500 the motor definitly goes into a “miss or retarded” fire. Thinking maybe it takes too much juice and causes other problems electrically. Once in while it will even back fire.

Plug terminals are tight, I did unscrew from the wire and both looked good but snipped ¼ inch off anyway. But if you hold the throttle steady at say 6500 it will open, run like ****, close and clean out, open and run like………about every 1-2 seconds until you squeeze it above 7-7200 and it goes like heck on up. Really do not see the rpms move much at all when holding steady due to being free wheeling on a stand as far as going above and below the open/close point. But definitely runs bad when in the mid 6 range when open on the stand. Hense would be the surge I felt riding it.

No 'codes' on CPU only the single flash at startup.
 

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Discussion Starter · #6 ·
Forgot to mention, this is with the TSS wires unplugged. Actually either way, makes no difference. So I guess if nothing else I assume my TSS is fine. Sucks when the sled is not!
 

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Are the valves in correctly and the return spring in place? I have seen where the valves were put in upside down and the exhaust pressure will start to push them open around 6000rpms. Disconnect the cables at the servo and watch the servo as you increase the rpms. The servo should activate around 7000 to 7200 rpms and then not close again until the rpms drop below 6700-6800.

FYI, always store the sled either full of fuel or empty. The smart valves in the tank can become slightly plugged, shut off, and will starve the sled for fuel. Put a fuel pressure gauge in the fuel line before the regulator and see if the fuel pressure drops significantly.
 

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Discussion Starter · #10 ·
I have not tried without the cables hooked up. I did put on a coil from my 98ZR that by the book was supposed to be the same and got the same results - engine miss when the servo opens.
 

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One of the biggest electrical current draw is the head lights. If you think it is a current drain problem, remove the headlight lamps. That will give you about 4 or 5 more amps to run the electrical.
 

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The engine picks up its tach signal from the crank senser on the mag housing, right above the recoil rope. If unplugging the head light doesn't help, that is what I would check out next. hope you find the problem.
 
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