I have a polaris indy 700 xc I am woundering about shaving the head for some more compression and if so how much to go to be able to still run premium gasoline?
First, Take some soft solder (twist 2 together if need be) bend it into an "L" shape and feed it into the spark plug hole PARALLEL/on top of the wrist pin.
Pull the engine over, remove solder and mic it. You'll want .045"
minimum piston to head clearance
I.M.O., maybe more.
Let that determine how much to shave off the head,
if you decide to go that route. Typically when I've replaced the stock POLARIS heads w/either SLP or HOT SEAT PERFORMANCE, I saw an increase on the gauge of Approximately 5-8 P.S.I. on the gauge. That's @ only 700 feet elevation, running 91 octane. For reference, on my 1993 Storm 750, I cut .020" off the heads PLUS drilled out the rivets in the "sandwich" style head gaskets and ran only 1 single layer rather that (2), Same on my 1996 Storm 800, after that I always purchased SLP/Hot Seat Billets.
Although I've always been a proponent of higher compression on 2-strokes, Jet-Skis, Snowmobiles, whatever, and everything I owned has/had higher comp heads, including my 1998 xc 700 w/SLP heads, however you may want to consider the following:
try e-mailing Sean,
seanmray@yahoo.com $100.00 for a "top hat" mod (
lower compression) to your stock head, he claims more power (and DYNOTECH
confirmed more power on the 2009 800)
throughout the power band. In the DYNOTECH write-up they spoke of similar results on the older 2002 800's as well. Jim @ DYNOTECH (585) 993-2777, OR
www.dynotechresearch.com
Hope this helps.