I THINK that the manual says to use 87-OCT, or higher. I am not positive about this, though. I run a mid grade fuel (86 oct. or better) and it hasn't "pinged".

 

Higher octane fuel won't burn any cleaner than 89 if your engine can't compress it efficiently(like a high compression engine can). When they list octane level suggestions in a manual they are matching the octane level to your cylinder compression ratio.

 

I agree, 87 is all that is needed in the prairie. What about with the new HL module?

 

Run mine with Regular and that is good enough.
MTD

 

I would like to dispell some old wives tales about gasoline.
Premium is more powerful than lower grades. False
Premium runs hotter than lower grades. False
Premium is bad for your engine. False
You shouldnt use Premium if your book says Regular. False

A gallon of refined gasoline has the same power, no matter what its octane rating. The Japs are no fools, given todays Eco problems, they will do nothing to upset us and possibly reduce quad sales. They also know that Americans would rather buy something new, that Fix something old. More money for them. So if regular unleaded is in U.S. Spam wordSpam word Spam wordSpam word Spam wordSpam word Spam wordSpam word Spam wordSpam word , thats what they will reccomend to use.
And most unmodirrfied quad engines will run happily on regular.
Then why use the expensive Premium ?

HEAT.

An overheated engine will detonate or Ping, very bad for your engine internals and also very expensive to repair. If you have, or EVER expect to overheat your quad engine, Premium , the higher octane the better, will keep your engine from detonating for a higher temperature.
Why take the chance just for saving a few cents a gallon ? If you have modded your engine in any way to make more horsepower it is even more important
I dont take that chance.

Prairie 650
Kodiak 400
Big Bear 400
Beartracker 250
Honda Xl 350
Harley Davidson Sportster
___Sarge
_________________

Post Extras

 

Yes, same rules apply to 2 stroke.
The main question is heat and IF. If there is any question of whether your rig will ever over heat for any reason, you will be glad u used premium. These same questions apply to synthetic engine oil. You really dont need it unless an engine overheats for any reason. Then, it may save your engine.
Why take the chance ? I dont.