I have a 2007 Can am Outlander 400 Max. I live in Phoenix, AZ with an elevation of 1200 ft. I am going to Ouray CO for several days to ride in elevations ranging from 8000 to 13000 ft. Is it a must to re-jet the carb? I would prefer not to, but I don't want to get there and find out the my ATV won't run. I have a Mikuni BSR33 carb with a main jet size of 133.7. What should I do?

 

With that much of an elevation change it is going to be really rich if you dont rejet.

 

Thanks for the response, I am seriously considering Dial-a-Jet. Sounds like a great one time modification with great reviews.

 

My typical mountain ride starts in the valley at about 4,000', and can go up to nearly 12,000'....all in one day's ride! I also have places where I ride that are below sea level, so I have kept stock jetting. You can rejet by decreasing the fuel, or by increasing the air.....

On a carburated quad, I install as many Thunder Products TPI Valves as I can in the airbox lid (from the same folks who make the Dial-a-Jet by the way). As I ascend, I open them up gradually for more air intake. As I descend, I close them gradually so I won't be running lean (lean can damage an engine!). Above about 9,000" I just pull the airbox lid off completely. This is a system that works very well! It's the easy solution for those of us who ride big altitude changes....and costs almost nothing.

http://www.thunderproducts.com/tpi_valve.htm

 

Only disadvantage....you do have to be carefull on deep water crossings, to not get water over the level of the airbox lid.

Or.....get the new fuel injected Rancher 420!

 

Good input, thanks. I ordered the TPI valve as well. Hopefully the combination will help

 

This is my first quad, if I would have known the issues sourounding the carb and altitude, I would have bought the 500 EFI model.

 

No matter what you do or buy your going to loose a ton of HP at 13K. Not much air at 13K!!!!