@wgc as well.

For only a few days, I'd probably just run it rich, even EFI machines run rich out here. Seems doubtful it will impact it to where it is struggling to run. I would definitely make sure the battery is in good condition and he has a freshly cleaned air filter.

But yeah, mostly he'll be riding at under 10,000 feet where 9,000 ft sounds appropriate. Getting up to 11,000 feet will probably not be possible because of snow drifts.

 

I took my prior 660 on many trips up to 12,000 ft and never had a problem, however ran into several on ATV's at elevation with fouled the plug(s), towed a few out for various reasons. Carrying an extra plug would be good insurance. J

 

good info, thanks guys.

Sounds like he made up his mind in the meantime and is just going to get another CO sticker for the SxS and bring that instead.

 

The 660 will do great with a stock engine and stock size tires.
When I added taller tires I learned c.v.t. mods were the answer to enhance the low speed performance; to compensate for the taller tires.
I do carry a spare plug, and suggest any one with any machine do the same.
My carb is stock and I replace the plug early each year for peace of mind, also I keep the engine in perfect tune.
Depending on the area, a wide machine might limit the trails he can access; we have 50" gates to stop wider machine access.