Here is the senerio,01 xc8 with slp twins(airbox mod ,heads,ect.. )pretty much the first time I've been able to run this sled.Temps +10 to -5F, wide open runs from a dead stop up to about 3/4 mile.After I got the clutching dialed in with my new hyperlite(awsome clutch),the sled consistantly runs slighty more rpm(about 100) and has better response(pulls to 8100-8150) with the reg. key timing setting.The egts read within 20deg. of one another,switch to the premium key setting it will gradually hit the target rpm(sometimes 50-100 less) and the egts are 100 deg different between the mag and pto.With the pto being the hot one,which leads me to believe the added timing of the prem. switch is'nt keeping enough heat in the pipes and the pto side pipe is the in the colder air and the unburnt fuel is giving it a higher reading.Anyone have any ideas about why it runs better with less timing?Or am I on the right track?I had the jetting pretty close.Does a motor running on the rich side like less timing?

I'd think you're on the right track, less timing = more heat in the pipe.

i agree with ivar. combustion event with more timing puts more heat into engine/coolant. retard timing maybe some charge(complete burn) ends up in pipe or ext manifold. never had the pleaure of having two timing curves on a sled (till this year) and have a egt in storage from my triple/triple days. was gonna keep in in mothballs till the BB kit goes on! i assume you are burning premium gas when on prem switch? has anyone ran reg on premium switch? if so does det come on? FYI my det was coming on during break in high load and when premix was gone it quieted down. ran premium.

I agree as well.
Ronnie my sled behaved the same was as yours during break in.

BigDog Racing

we run 3 of our watercross race sleds at -3 degs from stock timing. no problem with heat in the pipes 16:1 uccr comp @ sea level on 110 octane vp no signs of det..

Hows your jetting look? Too rich of jetting will keep heat out of the pipe.

Suggestion if your 01 has vents doors like my 02, try closing them and testing. I ran when temps were 0%F at w/o (100 plus) starting losing Rs. Closed the vents and seem to be OK.