'97 ZR 440 - Is it jetting?

[caseymcq]

I have a '97 Arctic Cat ZR 440 that I bought last year. With the splendid winter we had last year I only rode it a few times. The few times I did ride it seemed like it got horrible gas milage and I noticed when I parked it I would get a little black puddle under the exhaust. It also seemed to be lacking power in the low end but started to scream once it picked up rpm's. Is it jetted too rich? Is it much of a hassle to change the jets on Mikunis?

[fishingstar]

It could be alot of things jetting, float not set, clutch, belt.

Dan

[delcecchi]

how could the jets suddenly be the wrong size? Or did you just get the sled last year?

[Walleyehooker]

Most likely just need to clean the carbs. I just did 3 of them the other day. They get gummed up and floats stick etc. Pretty common on stuff that sits for a while. Not much to them and pretty easy to do if you are mechanically inclined.

[Walleyehooker]

Heres what they look like

http://www.arcticcatpartshouse.com/home.aspx?gclid=CILy8bPJmLMCFexAMgodmVYAAQ#/Arctic_Cat/1997_ZR_440_(97ZRA-1997)/CARBURETOR/97ZRA-1997-22-25/4422250731-962

Might be a video on u tube on how to take one apart and clean it

[caseymcq]

how could the jets suddenly be the wrong size?

[nitro640]

I bought the same sled new. raced it and trail rode it. it was arctic cats race sled for 97, it is very picky on jetting.

[caseymcq]

Thanks nitro.

[delcecchi]

Oops, my bad. I missed that you had just bought it. And that the previous owner? had "cleaned the carbs". I wonder if whoever cleaned them did it right.

[Whoaru99]

Safe to assume you had sleds before and this one is exceptionally crappy mileage, much moreso that the normally crappy gas mileage of a sled?

[caseymcq]

... And that the previous owner? had "cleaned the carbs". I wonder if whoever cleaned them did it right.

[Surface Tension]

If the main jet and idle circuits were dirty it would run lean.

Improper float drop, debris in or worn inlet valve(needle and seat)will cause a rich mixture. The choke, which in this case isn't a butterfly choke rather it is fuel enrichment. If that is sticky it'll run rich. You might notice a lot of vaporized fuel(white smoke) wafting from the exhaust right after shut down if any of those were the case.

What do the plugs look like? If it were running rich they'd be wet, black, or black soot.

How does it start, does pop right off or a lot of cranking?

Temps and two strokes. Your tuned for cold temps and you will notice a difference in performance between the warm and cold days. Maybe part of the puddle was water. If a sled is sitting and running, its common to see some dripping and much of that is water.

Back to the inlet valve. If that is leaking, the gas in the tank will can siphon out, especially if the check valve in the tank is bad or broken off. At the least, the fuel in the line will drain. That fuel will end up in the crank and after start up it'll soon be in the muffler. You will see it run out and eventually the white cloud.

[JosMN]

Never seen a 440 that wasn't very picky with the jetting. Sounds like your running fat to me. Take the carbs out, clean, inspect the jetting - put the stock jets in if they arent in already and go from there. Pretty safe to say that you can go one size lower on the main jet atleast and be fine - your mid to high range will be much cripser. Have done that with every sled I have owned with now problems.

[Whoaru99]

One of the caveats in messing with jets is how you're going to use the sled, IMO, and as Surface Tension indicates, what are the plugs saying.

While it's true that lots of sleds are fat and you can make them better, if you're doing long, heavy pulls and or WFO lake runs you're better off a bit fat than lean. If you're doing quick, short blasts I think you can get away with more lean.

[nitro640]

see if you can find an arctic cat performance manual for 1997, there should also be a jetting chart under the hood, follow that for what jets at what temps, if I remember right jet change for every 20 degrees. make sure the clips on the needles are in the right place. there is also pipe spacers, to adjust pipe length, goes between manifold and pipe. I think there was also a timing and pilot jet update when they were new that made a difference. jetted right that sled will be a rocket for a 440 and fairly easy on gas.

[caseymcq]

Thank you, you are all gentlemen and scholars.

[finnedfakes]

Ok, I realize your question is about jetting but like fishingstar says,it could be anything. You didnt mention what all you've checked. Have you done a compression and a leak down test? Are your clutches working properly? Spark plug correct heat range? Exhaust system damaged or been repaired? Are the reed valves( if equiped)damaged/worn? Carbs syncronized? Im just throwing this stuff out there because a fuel puddle and lack of low end can also be linked to low compression or a bad crankshaft seal.

[Ice Wolf]

I have a 97 cat but a 500. With the stock jets in the machine and burning gas with out ethanol in it and running the machine on a warm day say like 32 degrees it would run rough and rich. But when the temps are cold -0 it will run crisp. I used to Change out the jets back when we had mild temps and I ran it in the U. P of Michigan but now all of my sledding is around Vermilion lake in Mn Where the temps are a lot colder I keep the stock jets in so I just put up with it on warmer days.

Good luck!

[caseymcq]

I have not checked everything. Compression is good. Plugs are correct. Exhaust system is good. Reed valves - don't know. Carbs - not sure.

I guess with the sled being wimpy on the low end but screaming once it has built rpm's (breathing more) along with crummy milage and the puddle under the exhaust once it was parked was part of what was getting me to lean towards jetting but considering the other things mentioned I'll dig a little deeper.

Thanks.