Hi I'm new to cat thinking of pickin up sno pro 600 in good condition. Timing is on -3 can I run it -1 on 91 what esle should I look for what should compression be
more than likely at some point as that will be right on the edge. The SX program has a hot mid range. Most guys trail riding the sx program run it at -2 and jet accordingly. Once you get up to -1 you need to start blending in race gas. Cats base line for the sx program is 50/50 mixed 110/92 octane and 0 on timing. You would be better off running the XC program and running the timing at -1 or 0.
with the XC ECU program start at 480 main jet at sea level for 0-20 degrees F, timing on -1. You can send your ECU to cat's race department and they can put the XC program in it.