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corkdog96

race fuel(unleaded vs leaded)

13 posts in this topic

I am new to the whole 4 stroke scene. I just purchased an 08 yz 450f and was reading the manual and it says to run 95 octane or higher of unleaded fuel in it. Most race fuels are leaded and I was curioous if that would hurt the motor or not any help would be appreciated

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Don't run race gas unless your motor needs it. Your just wasting money. Your bike will run on race gas as it is now(stock) and it will be fine. But if your going to get the higher octane fuel you should drain the gas when your done riding. Use 93 or any gas that has a higher octane. 95's perfect if you can get it(can't get 95 where i live). If i had a stock bike i deffinetly would run pump gas. Race gas is such a waste of money. :banghead:

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The manual refers to 95 Research octane. There are two methods of measuring octane currently in use, Research (research octane number, or RON) and Motor octane (MON). The motor octane method is a more accurate indication of how fuel will react in a modern motorcycle engine, and always produces lower rating numbers for the same fuel.

Gas pumps in the US are labeled by the Research/Motor averaging method ( (R+M)/2 ). 91 Octane by this method is roughly equal to 95 RON, so US pump premium is generally all that is necessary.

Race fuels that are truly appropriate for the YZ450 will produce more horsepower (1, maybe 2), but cost nearly 3 times as much as pump gas in many cases.

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I am new to the whole 4 stroke scene. I just purchased an 08 yz 450f and was reading the manual and it says to run 95 octane or higher of unleaded fuel in it. Most race fuels are leaded and I was curioous if that would hurt the motor or not any help would be appreciated

Texaco sells here in Charlotte, NC 100 octane pump gas. I'd run it. Not too harsh on the carb but gives it the kick.

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I hope you're not going to promulgate the myth that an increase in octane provides a power boost.

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I use Monster brand 110 octane leaded fuel. I use it for various reasons:

1. My bike pings when its hot on pump gas

2. I have a high compression piston

3. Jetting is 100 times easier with it

4. Its the same stuff everytime I buy it, pump gas is not

5. I believe that lead cushions the valve seats, providing longer valve life

6. Motor stays spotless inside.

I could go on and on. I've used the race gas for years and I've never had a problem. I don't drain my carb, and I don't mind paying extra for it. It only costs $7/gallon, pretty cheap IMO.

Do you need it in a stock motor? No, but it won't hurt anything either.

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I use Monster brand 110 octane leaded fuel. I use it for various reasons:

1. My bike pings when its hot on pump gas

2. I have a high compression piston

3. Jetting is 100 times easier with it

4. Its the same stuff everytime I buy it, pump gas is not

5. I believe that lead cushions the valve seats, providing longer valve life

6. Motor stays spotless inside.

I could go on and on. I've used the race gas for years and I've never had a problem. I don't drain my carb, and I don't mind paying extra for it. It only costs $7/gallon, pretty cheap IMO.

Do you need it in a stock motor? No, but it won't hurt anything either.

7 bucks isn't too bad. try paying 135 bucks for 5gal of MR1. it adds up after a while. i understand everything you just said about it being easier to jet and how your motor stays clean and it provides a longer valve life, but what if you had your bike running on pump gas? you know how much money you could save to put into something else on your bike? thats why i say if your bike doesn't need it, then don't use it. the only reason i use race gas is because thats the only thing my bike will run on

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I've mix 1 gal. rocket fuel (100+ octane race gas) with premium pump gas and have had great results with valve life and engine performance. Just rebuilt the top end of my YZ450F and the valves and piston were still in super condition.

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642MX, reason #5 is my favorite, being a mechanic and all. I don't use race gas, don't need it in my engines, but I do add lead for that reason. Mike

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Engines built for unleaded fuel derive no benefit from using lead. My '03 had gone for over 4 years on the same valves without an adjustment and never a drop of leaded fuel.

My original point was that while there are fuels that will give you more power, and many of these do happen to be higher octane fuels, the octane rating itself has nothing whatever to do with the additional energy content of the fuel, and there is no benefit of any kind to be had by using more octane than is necessary to prevent detonation.

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I forgot to add reason number 7: It smells good! :banghead:

thanks for all the replies. I am going to be riding the bike around sea level in southern california at glamis(sand dunes) I have been going out there for years on 2 strokes and always had to run race gas at a 50/50 mix with 91 and vp c12 to keep the bike from pinging. I found that sunoco makes an unleaded race fuel that is 104octane but it has oxygen added. if I run that with the 50/50 mix will the added oxygen make the bike run lean. the cost for 91 around here is around 4 bucks a gallon and there is a place I can get the sunoco 260 gt plus for around 5 bucks a gallon so money isnt even a factor, I just want to do what is best for the bike and since I know nothing about 4 strokes I turn to you guys for your knowledge. so thanks again and also in advance for your input

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If the race gas is oxygenated, then you'll probably have to jet a little rich to compensate.

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