I thought I read in the manual that the 450r is suppose to run on at least 91 octane but could swear I read other places that it uses 87. Could someone please help me out?

 

i am not sure on the correct octane for the 450R but... you can always try 87 octane and see how it runs. higher octane is not always better as i am sure you already know. empty the tank and put just enough 87 to ride on for about 10 mins in the tank; take it for a ride and see if you notice a knock or ping noise coming from the engine. if you notice anything like that then you need to use a higher octane. that noise is detonation or pre-ignition. for those of you that dont know detonation is caused by heat from combustion igniting the fuel before the piston reaches TDC. it is very harmful if it goes on for long periods of time. higher octane fuels can withstand higher temperatures in the combustion chamber but also need that highter temp to burn completely, so if your engine does not have a high enough compression ratio using high octane fuel may actually be hurting performance but not the engine itself.

sorry about the long post but i think everyone should know this.

 

If you look at both pages 83 and 184 of your owners manual, they both recommend a minimum of 91 OCTANE pump gas! There is a misprint in the "quick reference" section of the owners manual (at the very back of the book), where it erroneously recommends 87 octane!

First off, anything less than 91 octane will trash this engine! This is an engine longevity issue, not a "performance" issue. You don't see much in the ATV mags, but if you read the dirt bike mags they are CONSTANTLY recommending a 50:50 mix of 91 octane pump gas and race gas for any high performance engines (leaded race gas so you get some top end lubrication). Do your valves a favor, and excede 91 octane for a margin of error against detonation.

I don't really like running race gas (even though my neighbor is the regional VP distributor and will give it to me at his cost!), so what I do is use KLOTZ OCTANE BOOSTER (http://www.klotzlube.com/storeProdDetails.asp?pi=50). I use 30 mL per gallon, added to 91 octane pump gas. This bumps the octane by +2.5 (a reasonable amount, but not excessive), so it gives a margin of error against detonation. Klotz has many additional benefits, like an ester synthetic lubricant for the top end (something that is absolutely essential!), a fuel preservative (in case your gas gets stored for a long period), it removes any condensation, and it isn't particularly expensive.

Great advice, from Dirt Bike Mag, July 05, page 76:

FUEL! by Gary Hazel

"We tell all of our riders who have new CRF, YZF, RMZ or KXF bikes that they should run a MIXTURE OF 50% RACE FUEL TO 50% PUMP GAS, even if the motor is stock. This insures that you always have good quality fuel in the tank. A few years ago fuel quality was great all across the U.S., but it has gone downhill. In some cities they use additives to help keep emissions down. These additives hurt the performance of the fuel and in the end hurts performance of our bikes."

"We have heard all the stories about valve issues in the new bikes. We have found that riders who live in the cities that use these environmentally friendly fuels seem to have more troule with valves that others do. In most cases we've found that the octane of the fuel in these cities is 91. When I worked at Kawasaki back in 1994 and the KLX250 was intorduced, we had motors coming back in to the shop that could use a set of intake valves after just a few hours. We found that DETONATION WAS THE MAIN CAUSE of this and when better fuel was used, this trouble all but went away. I think I can reinforce this with guys who are taking their new CRF250X's to Mexico. I have talked with guys who've said that they rode 400 to 500 miles and the valves have tightened up. Fuel in Mexico is very low quality, and these guys have told me that the bike was brand new befor the trip. Nearly every time they return after running that gas, you can plan on a valve job, because the top end takes a beating."

Also see this thread-- http://forums.atvconnection.com/mess...did/458625.cfm

 

wow! thank you for that information. i am going to drain my tank right now and going back to the gas station to fill up on 91. this kinda sucks.

 

I think reconranger gave enough info to answer your question but I would like to add motorcycle/ATV engines are high performance engines and they do require a higher octane fuel. Never put 87 in your tank.

 

DONT MIX FUELS

The cocktail that holds unleaded fuel together is different than the cocktail that holds leaded fuels together, the two don't mix. You can pour leaded and unleaded together but, you're not blending the fuels, you're combining them in one fuel tank. For the components that can combine, you end up making fuel that is more volatile and less stable. Meaning more prone to detonation. And then the components separate into different cocktails, usually making fuels that are not what you think, and the octane does not equal a half and half split, the numbers actually raise but the fuel becomes less stable.

Mixing leaded to leaded is ok sometimes, as is unleaded to unleaded. Just make sure one of them is not oxygenated. The corrosive attitude of oxy fuels can sometimes get very aggressive when mixing and form oxides that will be caustic enough to oxidize aluminum.

I can't say this enough to you guys , buy the fuel you need, don't try and make your own. If you don't have the facilities or the chemical engineering background, don't mix fuels.

 

i like to run vp c12. its good up to 15:1 compression and is 108 octane. the only thing i dont like about it is that its hard to diagnose the plug for lean or rich conditions.

 

White 7-How about a SOURCE for your information??? Sorry, but you can't expect us to believe something YOU say, just because YOU said it! Is this what they told you in Organic Chemistry class??? Did you read it in the Journal of Petroleum Engineering??? Where did you get your information? The trouble with a forum like this, is people can spout out anything they please. Without a source, the most weight any of it ever carries is that it is just your own personal opinion or experience (which is valid too, but we have to take it with a grain of salt because there is so much BS out there!).

Don't get me wrong, I too am no fan of race gas (even though I can get it at the distributors cost)! One guy in here called octane booster "snake oil", well I call race gas "snake oil".

The whole point we all need to take home here is that PUMP GAS IS CRAP! Its quality is dubious, and it changes greatly from one location to another. And it is unleaded, so it contains absolutely no lubrication for your upper cylinder. So, no matter who you are or what your opinions, you have to make a decision and do something! In my mind, mixing race gas might not be the best thing, but doing nothing is even worse!

 

By using C12, you have just retarded your timing about 5-6 degrees. I wouldnt use that fuel unless you have a very high comp. piston, and have advanced your timing.

 

There are a bazillion different race gasses out there. So, if you go that route, you are going to have to make your selection very carefully!