HI Gang,

Picking up my 2005 sportsman 800 efi today and was wondering what octane level of gas everyone recommends.

The dealer mechanic suggested highest octane available.

Thanks for any comments.

Regards Musky...

 

Whatever octane doesn't cause the engine to ping. Anything above that is a waste of your hard earned money. They all pretty much have cleaners and other detergents in them now.

 

We always run 91 in our quads.

 

high octane is made for high compression engines. it burns slower. If its not high compression you will waste your money. For example, and im not sure what polaris compression ratio is but 10:1, or even 11:1 is low compression so 87 octane works best for it. 12:1 is high compression,so you would use 91 octane. Using high octane gas in an engine that was designed for low octane will actually decrease power and performance,resulting in a waste of money. just read your owners manual it will tell you what you need.

 

Depending on the altitude you will be riding at the higher the altitude the lower the octane you want to use an a average 10:1 compression ratio. Here in Co our Reg gas starts out at 85 octane to give you a idea of what I am taking about.

 

Quick question.... so I am in Ohio, and have a carbed sportsman. If I were to come out to Colorado to ride, what would I need to do to ensure that my machine is running correctly?

(Do I need to just run 85 instead of 87, do I have to rejet and have it tuned when I get there, and have it jetted back to original and have it retuned when I get back?)

 

It all depends on the bike and how long you plan to be here and what altitude you will be riding at. You can get buy for a week or so on what you have but if you want optimum performance yes you will either need to rejet and/or clutch your bike. To rejet a bike it all depends on the bike and size of engine it has I would sujest bringing it here first, ride it and go from there. It one those trial and error things that you need to do. My Grizz tho EFI is also clutched on a dynoed for High altitude and will run most 800's off the road mainly as those machines are not running at optimal performance!

 

thats true dodge. forgot about that. i had to run 85.5(i think thats what it was) in wyoming. that was the lowest octane at 4,000 ft.

 

Your machine will run just fine on the lowest grade available at the pump with no issues.

I personally buy premium 91+ octane.....but the reason has nothing to do with the machines I put it in. I keep 50+ gallons of fuel stored in my garage. It may set as long as 8 months before it gets used up.....as fuel sets it loses its octane rating, so I buy premium for this reason.

 

I asked the same question when I got my EFI 450. The answer I got was that for the normal driver (non racer) high octane fuel gives no notable difference over plain old 85 octane you put in the car gas tank. I go through the five gallon cans of fuel so fast I never keep more than 10 gal of fuel in the garage at any one time. I had some 91 octane in my tank and i could feel no difference.

Fuel preference is like bike preference there are those who will swear by the high octane fuel but here in Cali fuel is expensive enough to be going out looking for 91 octane. I say save the money and use the 85 octane.