[ZR600_NS]

I have a 2001 Zr600 EFI APV with about 4000 miles on the clock. Lately it has been acting up some. It works fine at most engines speeds, but if I am operating at a steady speed with the engine right around 7000rpm the engine starts to hunt (for lack of a better term) or surge slightly. She doesn't seem like its miss-firing but surging, almost like you were slightly modulating the accelerator. It starts great and pulls hard right up to about 8300-8400 rpm, and the plugs look good. I have noticed a slight stumble on acceleration sometimes, almost like it loses its gas for for a split second, otherwise it has always worked great. I was wondering if anyone has run across this problem before, or has an idea what might be causing it? Thanks in advance.

 

[Steve-o-]

I am having this same promblem with my 00 Zl 500. It like loses all power and dives until you feather the throttle. I am right now geussing its the fuel filter, I HOPE. Or if that isnt the case go and buy a performance chip for it. Andsee what that does. Check the fuel system, all clear, check air intake. Work from the outside in.

 

[ZR600_NS]

I was wondering if it could possibly be caused by my Power valves? I think 7000rpm is around where they open. I have took the cover of the servo and watched them with someone holding up the back, and they seem to work okay. That doesn't mean that their working correctly on the trail though.

 

[vdo]

Brand new to this web site so I'm a little late to your thread. I've got a '99 Powder Special 600 EFI that has what sounds like the same problem. Before my last trip had my dealer go through the EFI and said everything was OK. Went to Dubois Wy. with some guys who've been riding for years and I still had the problem. Though none of them ride Cat EFI, several of them were sure it was a vacuum/air leak causing the sled to run a little lean. I bought my sled used and it had Black Magic chip, pipe and clutch in it. Dealer had changed back to stock chip when he went through the EFI. Even though the problem persisted, it wasn't as bad giving some credence to the theory. (BM chip runs leaner than stock so the if lean is the problem stock ship would make it run a LITTLE better.) I haven't actually looked for the leak and since I won't be riding again until next year I won't know for 8 months whether the problem was fixed. A place for your guys to look anyway. Good luck.

 

[Administrator]

Brand new to this web site so I'm a little late to your thread. I've got a '99 Powder Special 600 EFI that has what sounds like the same problem. Before my last trip had my dealer go through the EFI and said everything was OK. Went to Dubois Wy. with some guys who've been riding for years and I still had the problem. Though none of them ride Cat EFI, several of them were sure it was a vacuum/air leak causing the sled to run a little lean. I bought my sled used and it had Black Magic chip, pipe and clutch in it. Dealer had changed back to stock chip when he went through the EFI. Even though the problem persisted, it wasn't as bad giving some credence to the theory. (BM chip runs leaner than stock so the if lean is the problem stock ship would make it run a LITTLE better.) I haven't actually looked for the leak and since I won't be riding again until next year I won't know for 8 months whether the problem was fixed. A place for your guys to look anyway. Good luck.

Dubois, WY... sweet! I was there just 2 weeks ago.

Anyway... regarding the problem. I had a similar loss of power problem on my 99 Zr this year. The EFI checked OK. I was experiencing power loss around 5 - 6500 RPM. It felt like the engine was actually dying, but if you let off the gas it would return to normal running and then would be fine again when you got back on the gas.

I took it to my dealer and after they test rode it, tested the EFI, and checked the fuel pump pressure... they determined it was electical. So they found that the throttle "override" switch was worn out. (5,000 miles.) I don't know the exact name of the switch, but it is the circuit that will kill the engine if the throttle gets stuck open. Its like the TORS system on the Yamaha (throttle override system).

You may want to have your dealer test to see if this could be the problem. My repair cost around $200 since the entire right half of the handlebar needed to be replaced (and they charged me for having to haul the sled to a lake to test ride)

 

[Garganos]

Arctic Cat has been known to have Stator Problems. Have your dealer verify Ohms an Voltage tests on your stator. Before doing this though check that you powervalve servo motor is funtioning. The Servo should pull th cables open at around 6500 - 6800 RPMs, and close at around 6000 - 6500 RPMs. Check you cable adjustment. Also, did you check your clutches. AC usually needs clutches around 3000 miles if they are not properly cared for.