Need info on setting up a 2000 AC 300 4X4 for high altitude riding in the Rockies. Been going out there for years with my old YFM 225, and only had to change the main jet (15 minute job). Bought a new AC 300 4X4 for this years trip, and the only info I can get from Artic Cat (been like pulling teeth) sounds like I almost have to rebuild the carb. They say I need to change the main jet, pilot jet, and make a number of other adjustments. Does anyone out there have any experience with a 300 4X4 at altitude (at least up to 10,000). Any help appreciated.

 

Well all I can say is I have riden for three days at 4,700 feet pulling a meet trailer that weighed every bit of 500lbs and never noticed any difference with the altitude. Oh I also weigh 270lbs and the racks where loaded. That was on a 1998 500 Cat so I don't know what the 300 will do. I'm sorry if this info doesn't help.

 

Appreciate the reply Irichard. You're right, at that altitude on a 500 you wouldn't notice any difference. Probably wouldn't notice any on my 300 either. But, get on up to 6 or 8K and the smaller displacement machines start to suffer. The YFM 225s I've been riding needed one jet size smaller between 6 & 8K, and two sizes smaller above that to get decent performance. Sure, they would run without the jet change, but try to pull a load, or even just the ATV itself on really steep grades, and they just didn't have the power.

The jet change on the YFM was a piece of cake. Just drop the float bowl and screw one jet out and the other one in. Didn't even have to take the carb loose. Was hoping it would be as easy on the AC, but what the factory is recommending is a major disassembly job. Hopefully someone else has "been there, done that" and can give me some advise. Thanks again.