this will be the second winter for my wife and i on our quads, last winter they were stock and they ran great. now we have the basic goodies( pipe,air box mods,k&n, clutch kits, and reeds on mine.) i have herd from friends that i need to re-jet for the cold weather here in mich. is this true? i would never here the end of it from wy wife if they seezed up after talking her in to the go fast stuff. thanks.. 99-400sport 00-250 tblazer

 

I have the reeds, pipe, clutch kit also. I took mine out for a spin last winter in really cold weather, it didn't like it. It had no power and sputtered a lot. I took it home and broke out the Kodiak, which didn't have a problem.

I believe you go up a size or two as it gets colder. If I am wrong, someone here will put you in the right direction.

 

General rule is the colder it is the richer the jet.

 

You don't have to worry about rejetting until the temperature gets to about 10 below (f). You will notice a signifigant power increase in the very cold temps, be carefull because she might just sieze up on you. I drive an xplorer (400 2-troke)and in the 20 to 25 below with the stock 210 jet, my quad feels like its a 500cc 2-stroke. When it does this, it is obviously running to lean. (the same as just before running out of gas) I have seen people seize their engines because they did not re-jet. From experience, I would advise you to re-jet 010 bigger (in my case from 210 to 220) than your stock jetting, any more than this and you end up with what feels like riding a turtle. Hope this helps.

 

What a great post,since I to was wondering the same thing?I have a 00 400cc Xplorer.I'd say our Jan and Feb months usually run an average of around 25-30 degrees.I do like to ice fish alot and would be taking along the 4X4 Xplorer to make life easier and quicker.So whats the rule on this jetting thing?I know how to install them,im just not real certain if I need to for the little action the quad will see in the extreme cold,thanks,
Bill

 

I am all ready running a 250 main and put thee clip on the second from lowest notch on the needel, this is on a 99 400 scram i would rather run a touch rich and replace the plug then put a piston in. Plus since i did this from a stock 230 man what a power difference hell damn near went over back wards with out trying i like it this way but that is just me. Run rich and ride run lean and walk. Your choice.

 

Good idea. I am wondering if altitude will play a part in this also. I ride in the 2000'-6000'range. Did the dealer leave stock from the factory jets or do they compensate for the area they sell in? Should I also increase jets size in my 500HO, got down to 7 the other day.
Also helmets? Do you guys/gals switch to street full face helmets in the winter? What do you use?
Thanks.

weetoots

 

You hab better raise your main 10 or you might seize it,I did about a month a go the temp went below 50 and it seized all I had done to it at the time was Hpd pipe bored carb HPD two piece head trail chamber.

 

You obviously did not re-jet properly after your mods. 50 degrees temperature is not cold enough to require re-jetting.

When you purchased your quad you should have gotten a few pages along with your owners manual called "owners manual supplement". All the specs including a jetting chart are on this.

Example 1999 Xplorer
0-3000ft below 0 degrees f 227.5
0 to +40 217.5
+40 to +80 210
+80 and above 202.5

Hope this helps

 

I have been riding for 11 years in very cold temps and have never heard of anyone having to re-jet on a four stroke due to cold temps, nor have I ever heard about anybody seizing their engines. I believe that this thread is more for the 2-stroke polaris owners.