my brother has an 02 xc 600, i heard rumors that you should always leave key on reg regardless of what type of gas you run? Any truth to this

Thanks Machine

No truth. I have a '01 600xcsp, virtually same motor, and run on premium switch all the time. You need to run good quality premium, leave jets as stock, and you should be fine. I get about 2 MPH on top end by running on premium.

I use my premium switch on my 02 xc 700 had no problems use it only when i know I have good premium fuel in the sled. raced a 800 doo last year got smoked the first time. When I switched it to premium was about a sled and half behind him. Sled seems to pull harder in premium mode.

If you leave it on " regular " you will never get full timing / power. The idea behind the Premium setting is it will allow for more timing advance,
which is why you need to run the higher octane fuel for that setting. I only use 93 or Sunoco 94 in my 2002 Edge X 800.

I think the reason you may have heard this is the 02 600 had some over heating problems in low snow conditions and even on some hardpack. I fought my wife's sled all last year. Hers has the m10 suspension. Took it back to the dealer and they installed another heat exchanger in the rear, reset the throttle positioning and installed a new coolant bottle. The premium switch on the key advances the timing and would make the sled run a little warmer. Also saw a blurb in snowtech magazine late last season or early this season about this problem. Some guy wrote in and told exactly what he had done to resolve his overheating problem. We haven't had a chance to ride yet this year so don't know if any of this will help but most of what they told me makes sense.

thanks for your thoughts