the 98 summit 670 was just the regular motor, late 98 there was a x model released with the high output motor. the ho has higher compression head, bigger carbs 44mm, more timing, that is all i know for sure. both models had 136 inch track I think. the color scheme is different. the 99 would have dpm. not sure if 98 670 had dpm, it may just have HAC-high altitutude compensator.
i said 99 would have dpm, so wouldn't the 98 X. If both are 98 models I would assume color would be same for some reason I was stuck thinking about 99 models. sorry for any confusion. maybe somebody else knows some more specifics?
I am pretty sure that the regular summit had 8 tooth drivers and a 2" track while the x came with a 1-3/4 track with the 9tooth drivers to maintain the approach angle. also the H.O. vs the regular 670. Hope this helps.
A forum community dedicated to snowmobile owners and enthusiasts. Come join the discussion about performance, troubleshooting, trails, maintenance, riding tips, modifications, classifieds, accessories, and more!