Premium fuel needed????

I recently did all the "free mods" for my 06' WR450 and am wondering if someone can tell me if premium fuel is still needed?



Its best to run 91 premium in any bike taht is stock or not on race gas. Especially since it is a high-revving four stroke.

Definately run 91 octane, race fuel would be a waste of money.

My 07 has a sticker on the front fender that says it requires premium fuel...FWIW.


hmm in aust. our ordinary unleaded is 93octane premium is 95octane and there is ultimate98 available and a 100octane which has ethanol.

The octane rating specified in the manual is the Research Octane Number, or RON. The manner in which the octane rating in the US is expressed is the Pump Octane Number, or PON, which is determined with the formula RON+MON/2. MON is short for Motor Octane Number which is always lower than the RON. Generally speaking, if you have a rating of 92 at the pump, you can be fairly certain that the gas has a RON of 95 or better. Here's a great article that explains it much better than I can, complete with graphs and charts :lol::applause: ...SC

Thanks for the article clark 4131. I've read a lot of fuel articles and some get very confusing. This one was simple, straight forward, and easy to remember.

I always run 91.

None of the mods change the compression ratio. And, with the mods done, you're squeezing even MORE fuel into that little combustion chamber - probably need the premium more now than before.

i've run 87 and 89 in my uncorked 450 05 and havent noticed a difference.

There's some stuff going around MN about also using non-oxygenated fuel. BP is generally a good source.

I have a WR400F and have used almost exclusively 87 0ctane for years with no noticeable problems. I have listened for pinging, checked the plug for preignition damage and have detected no problems (it may even have the original plug). This bike is ridden hard both street (Sportmans Class fashion with street tires) and dirt and has definitely not been babied. It is one of the most versatile and durable bikes I have ridden with plenty of hours on it.:banghead:

Anyone one else have any actual experience running 87 Octane? Has anyone detected any detonation or preignition running lower grade fuels?

Don't you get a bit more power out of race gas? I have read that it runs cooler and burns more efficent. Something running cooler and more efficient gives more power right?

I occasionally buy some 100 octane @ about $6/gallon. Mostly when I go trail riding.

Oh yeah it smells awesome :banghead:

What about octane boost in a can? Would that help?

I usually use 94 if the station I get it from is open if not I'll get the next highest rating.


Don't you get a bit more power out of race gas? I have read that it runs cooler and burns more efficent. Something running cooler and more efficient gives more power right?

Higher octane does not necessarily translate into more power. The octane rating is a measure of how resistant gasoline is to the abnormal combustion phenomenon known as detonation (also known as knocking, pinging, spark knock, and other names). Higher octane is needed the higher your compression ratio. Higher octane in an engine that doesn't need it, actually produces less power. The same is true for an engine that needs it but doesn't get it, but then you get the added bonus of the detonation which can actually damage the cylinder. So, in order to get the most energy out of your bike based on the fuel, you need to determine what is the lowest octane fuel you can use without getting pinging...:banghead:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now