08-11-2005, 06:35 AM
Ive seen different aftermarket heads available for the 800 series3 engine, but Ive also seen different companies offering to mod the stock head also.
Anyone tryed this? If so how were the results?
08-11-2005, 10:02 AM
They bore out the combustion chamber and install a dome this improves the desine and Hp it still looks stock some times refured to as the cheater head but not near as good as the after market heads like Cudney witch improve cooling around the chambers a head change is a big improvement as the stock chamber is proen to detination .
08-11-2005, 10:55 PM
Absolutely what MyDoo said. Your best bet is to remove the stock head, open the garbage can, deposit stock head, buy billet head that has some actually COOLING capacity and install. Even the 700's have decent cooling design. The stock 800 is a joke and if you make a cheater head, then good luck is all I'll say!
08-15-2005, 07:04 AM
i installed a polar head and shim kit on a 2001 mxz800 it worked very well with no problems ..i put approx 4500 miles on this head ,the key is to get your squish right .......if your interested i have it for sale $100.00 cdn funds ...when i sold my sled i put it back to stock ....
08-16-2005, 05:45 AM
Check out RK Tek. I have their head on my 700 and a buddy has one on his 2002 Doo 800.
Here is alittle bit about what Kelsey has to say about the Doo cooling. Click the link below to read more.
Ski Doo's Series III engine's stock "conical" combustion chamber head is a very inefficient head design that has a very poor combustion efficiency. Our "Hemi" design* utilizes tighter squish clearances and a narrow squish band which will increase combustion efficiency and produce a more centralized push on the piston, thus increasing power. End gases will NOT be trapped in the squish band where they can't contribute to the power process. Squish velocities are calculated to insure a safe reliable combustion process.
The added cooling ALONE! will greatly aid in maintaining performance. The stock head has insufficient cooling flow for the engine. This allows for an engine that is running much hotter than it should be.. which, in turn, robs power! (and nobody needs that)
For those of you who are un-happy with the fuel economy (or lack of it) with your Series III Engines.. Adding the head, ALONE, will allow for* MUCH leaner jetting thus greatly increasing fuel mileage!! For example... 2001 800 Twin.. Stock = 500 main jet.. Installing the head, ONLY, you will run a 420 main jet!! Can you say " MORE FUEL ECONOMY??"?
RK Tek (http://www.2strokeheads.com)