summit 670 - Snowmobile Forum: Your #1 Snowmobile Forum

mxnate116 · 07-07-2006, 03:13 PM

are there cheap mods for the summit 670? i was thinking of getting rid of the airbox for two k&n filters with snowchargers and rejetting. is there anything that can be done with the exhauste valves? and i was curious to the benifits of a rotory valve with other then stock timing. would this help and should i have more or less timing? thanks in advance for any help you can give.

**smallengineguy** · 07-08-2006, 07:28 PM

The biggest bang for the buck is clutching all the way. You'd be amazed on how tuneable the Rotax clutch is. RAVE's are pretty much fixed like they are. Same with timing, you'll see a minimal improvement comparable to what can happen to the motor with too much timing.

BRPforlife · 07-08-2006, 07:49 PM

Since it's a summit I'll assume you do a lot of powder riding. Those K&N filters will ice up from melted snow, and a wet filter is never good! I'm with SEG, throw a clutch kit on it! If you want a little more low end grunt than dropping a tooth on the top gear will help. You can use your stock chain but expect to lose a couple mph on the top end.

mxnate116 · 07-08-2006, 07:57 PM

thanks for the help guys. so for the clutch do i get a new spring or weights or how do i tune it? also is there any gain from a wave/lightweight brake rotor?

**smallengineguy** · 07-08-2006, 08:33 PM

The things you suggest are all minimal gains for a LOT of cash...Buy a clutch kit specific to what you want. You can get drag kits, mountain kits, etc. Do a yahoo search for "snowmobile clutch kit".

skidoo kid 102 · 07-09-2006, 12:46 PM

check out www.mcbperformance.com they have some pretty good stuff for the 670.

BskidooC · 07-14-2006, 07:33 PM

670's are awesome with dual pipes and dual cans
and they have a nice low sound
you might want to consider that