I live in Wisconsin and rarely ride below 0 degrees. Seems like all my friends with polaris are dropping at least 2 jet sizes and some more. I know I should "read" my plugs and know how to do it but was just curious how many of you out there have dropped jetting sizes--it makes sense to me the factory would have them set rich for ultra cold weather and maybe a slight cushion with varnish. How much fuel and performance improvement might you see from a drop of 2 sizes in jetting??

I dropped 2 sizes on my 01 XC 600SP, and the plugs turned WHITE immediately, so I limped back with the choke on.
I had a Pipe, can, reeds, so that affects things too.,

YOU NEED to read the plugs. There is no other SAFE way!

I was told by the dealer that one size is pretty safe, after that you're on your own.

I forget again how cold 0F really is. Your machine comes with a jetting chart though, you should be able to follow that. And remember that if you're jetted lean and it gets colder than normal out, just don't hold the throttle pinned for too long and you should be safe.

nobody wants to go out on a limb?
you can run 2 sizes smaller than factory suggestion for the given temp, but plug reading and piston wash, supersede this.

I dropped 2 jet sizes this winter on my 2000 XCR 800 and have experienced only a small amount of increase in fuel economy, but it did a hell of a lot for my performance in warmer temperatures. It used to bog while flying down the lake when it was close to zero degrees out, now it's great. I have still had it out in -30 this year (with the dropped jet sizes) and experienced no problems. I went from 440's to 420's. You won'y have any problems whatsoever dropping 2 sizes in your neck of the woods.

Originally posted by kraky@Mar 3 2004, 04:29 PM
I live in Wisconsin and rarely ride below 0 degrees. Seems like all my friends with polaris are dropping at least 2 jet sizes and some more. I know I should "read" my plugs and know how to do it but was just curious how many of you out there have dropped jetting sizes--it makes sense to me the factory would have them set rich for ultra cold weather and maybe a slight cushion with varnish. How much fuel and performance improvement might you see from a drop of 2 sizes in jetting??
You have to establish a baseline,to do this mark down the curent temperture,barometre,barametric pressure and humidty for that day and mark this down.The best is an altimetre elevation,this gives u everything in one.Just mark down the temp for that day and have a place were u can go wide open for at least 800ft.Put in a fresh set of plugs,jet down at about 2 sizes smaller to start(from factory),and go wide open for 800ft. and hit the kill switch while ur hand is still on the throttle.Now take out ur plugs and check the ground and it should just start to go to the bend of the ground(lite brown),also the elictrode should have a little silver ring on the edge and working it's way down alittle.If it's not this color try again with another set of plugs until u get the perfect burn.When u do get it burning right make a note of the temp. and get yourself a pocket tuner(main jets sizes)from this u can establish ur jetting perfect for different temps.

i dropped 10 sizes in my 97 500 it wouldnt run before in the warm weather now it runs good. i hate the stupid charts they should just shove it up there a$$e$!! i had a hard time getting 40mph out of it and now i get 100 out of it now that i fixed the head gasket

GET THIS GUY OUT OF HERE!!!!!

I WILL 2ND THAT PLEASE!!!! :(

3RDed

I have an 02' XC700SP Edge X and put a Trail Dominator Kit on it from http://www.legendperformance.com/. This thing rock and rolls for mileage and and the engine is so much more efficient compared to stock.

At any rate, that engine as well as the 600 is jetted very fat. I dropped 2 sizes and the plugs are a perfect tannish color. The pistons have very little carbon build up, due more so to the different (clean burning) heads than anything else but the jetting helped as well. This is a great aggressive trail combo although as mentioned before I would not hold it wide open very long if you do ride in -0 F conditions.

Side note; I use Legends ZX-2R oil and have found it superior to anything else out there. Better mileage, virtually smokeless and no more ring blow by that the other synthetic and VES oils have. Plus its a mineral based oil for $20/gal VS 32-35/gal for the synthetic and VES oils and is compatible with other oils just in case you get stuck somewhere with no oil. I still experienced valve build up but it was not as bad and cleaned off much easier than the others. Polaris and Cat valves need more attention than Doo's because of the tighter valve clearances. Legend is working on a additive to help with the valve build up. Contact them for more info. if your interested. BTW, I'm not affiliated with them, just an extremely satisfied customer. Good shops are hard to find these days!!!

More than you asked for but hope it helps you make a more educated decision.

Thunder Dan

Originally posted by polaris indy 500@Mar 11 2004, 10:25 PM
i hate the stupid charts they should just shove it up there a$$e$!!
Are you a combustion engineer - NO

I am.

So shut the hell up with giving people advise.

ok u tell me sumthing it said to run 350s in it!!! and know i am running 260s now what do u think!@!!!!! so lay off i am not lieing!!!!!!!!!!!!!!!!

OK i have a question. My temp chart doesnt go this warm, but in the spring i'm gonna be crossing some water, and it will be around 45-60F. Just wanted to know what jets i should be going for here. My manual only goes down to 310's and thats at like 40. I'm thinking maybe 290-280's? Thanks

Chris

one jet size for each 10°.