I am going to Colorado hunting and will take my new Rancher 329cc 4X4 - has anyone used their ATVs at this level (10,000 ft)? how did it run? or did you have to change the jet? Honda says that over 3000 ft that you should use a .125 jet vs the .130 that is std. and this is good to 8000 ft. so what happens at 10,000 ft.?

 

In my opinion the info given to you was rather conservative as to what might be required at just 8000' elev., never mind 10000'. That said, I'd suggest you take along the 2nd & 3rd jets leaner than your stock 130. If it were me I would even take a 4th just to be sure. They don't cost that much & you might need them another time. I would try the 3rd leaner first & do a test & plug read. If still on the fat side then the 4th surely would do the trick. With the relatively smaller displacement you have, jetting will make a lot of difference in power at 10000'. You may find that a change in the jet needle is necessary from the 3rd position to the 4th if you see loss of power in the 1/4 to 3/4 throttle range. Since none of this is an exact science, hopefully you'll arrive in time to sort it out beforehand.

 

Ran my Rancher at 10,000 ft. a couple of weeks ago at Coyote Flats (Inyo National Forest, near Bishop, Ca), with stock jetting. I didn't want to rejet for a short trip. It actually ran OK. There was of course less power, but it wasn't that bad at all. I was pleasently surprised!

 

I run both stock Ranchers with origional jet near 9000ft regularly in Utah, No problems.

 

This may not help your decision to jet or not, but here goes. I live in Colorado (7,000 ft), and just purchased a Rancher 4x4. Just prior to going hunting this year (@10,000 ft), I rejetted with the Dynojet kit; specifically, per their instructions for greater than 6,000 ft, and added a K&N with outer filter. On our trip, it ran great. The first elk down we pulled out with my buddies 350 Big Bear. I ended up hooking on to him to pull him, the trailer, and the elk up a pretty steep rocky grade. The next elk down, same area, I pulled out alone up the grade with no problem. During the whole week, I spent most of my time in 3rd gear. Plenty of power to pull the hills at that altitude.
I hadn't run my atv at that altitude prior to the rejetting, but can say that it did great afterwards.