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Discussion Starter · #1 ·
Hi everyone, I've been reading for a few days, great forum!

A few weeks ago I picked up a 2000 ZR 600 carb with about 5500 miles. The person I bought it from said it was cutting out like it was starving for fuel and it hadn't been run at all this season and he had previously found water in the gas.

It has V Force Reeds, air box is stock. Stock pipe with a straight - through can (which I changed to a stock can I bought on e-bay so I wouldn't wake the wife when coming home late). Pilot Jets: 135, Main Jets: 350, carb adjustment screws out about 2 turns, needle clip at #4 (next to lowest / richest). It has yellow with green stripe primary spring, and yellow secondary spring.

I immediately pulled the carbs and had them dissassembled and cleaned by a local sled service shop, drained and dried the tank and replaced the fuel filter and pickup filter in the tank. I blew out and checked all the fuel lines, etc. I put it all back together with new plugs and a full gas tank and it fired right up. A few trips around the yard and it seemed to run good on the straights but intermittently cut out after jumps, and in hard braking. After it warmed up it seemed to do it less / not at all. I check the TSS and it had already been cut / taped.

After a few evenings / days of riding - 100 - 200 miles, I noticed the following:
1. It still cut out intermittently, but very rarely, and mostly when cold and after hard braking or landing a jump. Once when I was running low on fuel it cut out really bad and it felt exactly the same.
2. It won't rev over 7500 RPM, and won't go over 70. It just doesn't feel zippy on acceleration like I would expect.
3. The clutch seems to engage at the normal RPM, somewhere between 4K and 5K, but it jerks
4. I am getting 5 MPG or LESS! - I ride quite agressively so I didn't expect 15, but this is just crazy.
5. There is a little oil coming from the gaskets on the exhaust y-pipe
6. The right side of the track was chewed up, and the track in general periodically made a rubbing noise.
7. One day I did manage to get up to 80 after it was good and warmed up, upon which the speedometer quit.

After the speedo quit I rode it for about 100 miles, fairly hard, and the fuel economy just got worse and it felt sluggish. I tried putting the exhaust can back on but that didn't seem to help. The snow went away this weekend so I got it inside and started poking around.

1. The speedo adapter pin was sheared, and the drive shaft bearing on that side was dry and shredded and dropped about 1/2" down and rear-ward. The bearing from the chaincase side looks good (I think I saved the chain and gears by catching it in time - thanks to this forum!), when you slide it on the speedo side it wobbles a little.
2. It appears that the track was out of alignment (probably from the driveshaft being dropped) and was rubbing on the rear mounting block on the right side and chewing it up. A few of the idler wheels were almost frozen.
3. The ceramic insulator on the plugs is dark brown, and there is a hunk of gunk where the ground electrode meets the threads. Plugs are oily.
4. There is a little bit of oil behind and below the primary clutch, and more from the exhaust gaskets. Through the spark plug hole the top of the pistons look like oily charcoal.
5. The belt that was on there was a little narrower than the new spare, both are AC and the correct part #.
6. The airbox boot was cracked open on one side. The airbox boot is covered with fuel on the inside.

My current plan:

1. Replace all four bearings, drive shaft, speedo pin, brake pads (while I'm at it), the broken skid wheels and sliders (why not), and the airbox boot. Put it back together with the stock exhaust can, new belt, tension and align the track properly, and test it out (although I won't really be able to test it until next winter).
2. Resolve the cutout / sluggishness / bad fuel economy / oil leakage issues, IF they are still present.

My questions:

1. Is it possible that the machine felt sluggish and burned a massive amount of fuel because the drive train was so screwed up?
2. If not, do you guys have any suggestions on where to start troubleshooting? - needle clips, jets, screws, electrical, etc?
3. Should I worry about the leaking oil? Will it lessen when It stops running so rich?
4. Any preventative maintenance that is mandatory at this mileage (5500), not knowing the service history? Is it time to do pistons / rings, etc?

I know this is a long post, thank you all for you wisdom and experience!

1,778 Posts
The blue masking tape may cause poor plug contact ;)
They look like they may be over heated as the electrode shows signs of rounding off, there may also be some detonation happening if those are specs of aluminum on the electrode.
With the drivetrain as messed up as it sounds it sure will cause a bunch of the symptoms you are experiencing, not sure if it would cut the MPG in half but it would be a good place to start. The slushy snow in spots and snirt cost me 15% in fuel economy on Sunday (I have a tempa flow so the temps are compensated for)

5 Posts
Discussion Starter · #4 ·
Well I replaced the drive shaft, bearings, and made sure the skid was in good working order and put it all back together with a new belt and also repaired the airbox boot. I aligned and properly tensioned the track and tensioned the chain finger tight + 1/4 turn.

I took it out and opened it up (on frozen grass) and the belt slipped. After going through chain and track tension I put the old (narrower) belt on and that fixed it. Could it be that I need another shim in the secondary clutch to run a new belt? Maybe the previous owner took one out to compensate for belt wear.

It was still sluggish so I assumed it was running rich. I can see clean piston through the plug holes. I changed the main jets from 350 to 340 and the top end was great but it was still sluggish off of idle. I dropped the needle one notch (leaner) and now it seems to run great! I still need to get in some good mid and full throttle runs and check the plugs and wash, but It feels and sounds right!

The only non-stock thing on this sled is the V-force reeds. I was told that you can lean it out with the reeds, plus these are jetted rich from the factory. The combination was just too much. I can't wait to try it out and see how the gas mileage is!

Snow is bearing down on us right now 6-12" in the next two days! :super_happy:

Thanks for all the info on this forum, it really helped me out.
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