I need to re-jet the carbs on my 2006 400 and 2006 500. The elevation I ride at ranges from 2500 - 7000 ft, and I mainly ride between 2500 - 5500 ft. Being a novice at rejetting ATV's, what size jets do I need for these two bikes? Where is a good place to buy new jets? Any help would be greatly appreciated.

 

When I ride in colorado I typically take my 06 500 from a 138 main jet to a 132, but that is for 12000 to 13000 feet max. I run the 138 in kansas @ 1200 feet so you can see the difference isn't that great. What size main jet are you running now and what is the elevation where the machines were purchased? The dealer that I deal with has told me in the past that the cats are jetted a little fat from the factory, and most dealerships are supposed to jet the machines to the elevation that they are sold at. When riding from sea level to 5 or 6000 feet, the jetting isn't as big as a factor as it is when you get around 8 to 10000 feet. The main thing when rejetting is to know how to read your spark plug. The only thing that I can say when changing jets when you go leaner that you need to be careful not to jet too lean, especially on the air/oil cooled motor on the 400, or you can have big problems with heat damage. Let me know the jet sizes that you have now, and also what is the normal temperature that you ride at? Temp isn't a huge factor but it does have some effect. As far as where to buy jets, any stealership that sells KEHIN round jets, which is most of them, will work. I hope this helps

 

Just buy a dyno kit they come with all different kinds just put in the jet for the right altitude.

 

Do a search for 'air jetting', this may help you out.
As you know correct air/fuel mix is the key. Not only can you keep changing jets but you can also do the opposite and change the amount of air, to obtain a correct mix.
Air jetting is far less expensive, $3-$6 for a setup. It will also allow you to run the largest fuel jet that your machine can handle by getting more air to the engine. You can plug one or two hoses with a bolt for a richer mix when needed. And it only takes about 15 seconds to do.

 

<div class="FTQUOTE"><begin quote>Originally posted by: ArcticCat4ever

I need to re-jet the carbs on my 2006 400 and 2006 500. The elevation I ride at ranges from 2500 - 7000 ft, and I mainly ride between 2500 - 5500 ft. Being a novice at rejetting ATV's, what size jets do I need for these two bikes? Where is a good place to buy new jets? Any help would be greatly appreciated.</end quote></div>

I run a 150 jet in my 400 and change the air/fuel mix by changing the amount of air.
You will need to know how to read a spark plug or do a WOT test.
Here is a simple method to get you close. While riding bring the engine to top speed (or close to it) and start to engage the choke if the engine picks up speed or smoothes out then you need a larger jet. If it surges or stumbles then you need a smaller jet. Also at full throttle if you back off to 7/8 throttle quickly and the engine smoothes out then you need more air or smaller jets
By doing an 'air-jet' kit that I developed you can change the air/fuel mix on the fly so to speak within a few seconds. And enjoy a full day of riding and can even change the mix several times during the ride for varried altitudes and weather conditions.