Shaving head on polaris indy 700 xc

[polarisrider30]

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?



Thanks to all for ur info i will do some thinking!

 

[Dirty10]

I have had several 700s in the past and have cut the heads on all of them some of them I have cut at 50 and 60 thou and some at 70 and 80 thou. I thing I have a cut head at home I would sell you for 50$ plus shipping.

 

[snowx22]

elevation

what elevation are you going to run at? I think if you are going to run at sea level you probably don't want to shave any and run premium. If you are going up in elevation thats a different story, or if your going to run some better gas. I only shaved .010 off my 800 head because the squish starts to get a little tight, so watch for that.

 

[Kraven]

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.

 

[xc6rider]

I started running into fuel problems and bad detonation around .045-.05 800ft elev.
Stock should be around .065-.07 if i remember right. squish on a 98 600 By cutting the head, you aren't just creating more compression, you are also changing the squish angle. Their is alot more design in heads than just cc's!

Compression will rob topend HP, but gain torque. This is a decent "general rule" to toy with.

They may have found that with the lower compression heads like mentioned above.

I could understand seeing that on a dyno, but I wonder what the Torque ft/lbs were at after lower compression. I could be wrong, but i'd almost bet the torque came out lower. Has my ear's perked though, want to hear more of their findings.

 

[FEZ]

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?

Have you got the clutching/jetting gearing where you want it?

The gains you will see are minimal with just a head cut and push you closer to the egde. I would rather have 130 WFO all day HP then 132 nervous, not sure about WFO unless the conditions are right.

Not sure what your use for the machine will be, maybe this is the last piece of the puzzle, just my 2cents.