Could someone pleas tell me the truth about premium gas? Some people tell me not to run it in a stock engine because there's not enough compression, and then some people say it is fine to run. Someone please shed a little light on this for me.

 

You don't need to run premium in a stock machine. Not until you start raising the compression, shaving the head, or changing out to the billet head with different domes. It's not gonna hurt anything, you'll just be wasting your money. I thought cycleworks had some info on their site. You can do a search on fuel, seems to me some people have had some informative postings in the past.

Happy trails,
Ken

 

that right,on a stock engine you won't see any gains,their all for 87
octane applications,droping 92 octane gas in the tanks just maybe the engine will run cooler but that it,on restrictives stock motor form the engine get more build-up in long term while running premium gas.

 

I have a 1992 Yamaha Timberwolf, and i have always been using premium gas in it, the motor is like new and still runs great. Im not saying its better using premium gas, im just saying that it did'n hurt mine.

 

The Real story about Octain levels and there performance properties.

87 octane = More power, Stronger cleaner burn, More heat, Easier starting, More prone to detonation..

91 Octane = Less power, Weaker less vilont burn, Less Heat, Harder to start, More resistance to detonation.

Running 91 in a 4 stroke atv rated for 87 is ok but pointless. You will not gain anything other then maybe a cleaner engine if your fuel company adds fuel cleaner like tecron to the fuel. You are also in a way retarding the ignition timing becasue it takes longer for 91 to ignite and burn (also robbing you of HP.)

Running 87 however will give you more power and easier starting.

Now this is were things change. You have now taken your stock atv motor and turned it into a high compression engine. Yes 87 will still give you more power but will also give you more scrap metel. You need 91 becasue it burns slower and is harder to ignite giving you the resistancea to detonation and proper timing. 87 in this situation might just ignite on its own under the compression with out the help of the spark plug and could seriously ruin the engine.

Now in a 2 stroke atv, snowmobile, anything rated for 87 that is 2 stroke i would only run 91. Two stroke engines are very delicate when it comes to detonation and pre ignition. Running 91 will give you a margan of safety and also help if you come across bad gas which may have lost some of its octain rating. 2 stroke engines IMO can last just as long as a 4 stroke but most of the time are killed prematurly by a Pre ignition cause by bad gas or carbon build up and using 87 gas.

Hope this helps.

 

Modquad pretty much hit the nail on the head. Here are the FACTS Gasoline Facts

Different octane gasolines do NOT burn hotter, faster, colder, or slower than other rated octane gasolines that is the biggest misconception out there. Ocatane rating is simply a numeric rating to measure its resistance to detonation.