New (to me) 1980 Yamaha Maxim 650 Fuel Question

[goser]

Hello all,

I just bought my first bike, and I have a question about fuel. The fellow who sold me the bike said it doesn't run well on regular gas--he's been using premium. Now so far as I know a higher octane gas should just resist dieseling, and he said it just 'lacked power,' no knocking or anything. So, with this compression I should be able to switch back to regular, right? Anyone have any ideas what might have caused the problem or what i might do to fix it?

[Johnj]

Just try a tank of regular. The bike will let you know if it requires Hi-Test.

[The Doctor]

the higher the octane the more heat and preassure the gasoline will need to ignite. If your bike has a compression ration for a high octane and you use regular you will get knocking and eventually even holes in you pistons.

I believe that bike has a compression ratio of 9.2:1(I could be wrong on this). I would use if not premium a step below but I wouldn't use regular.

Anyways you can get the manual and see what it calls for.

Good luck

[jonnythan]

Hello all,

I just bought my first bike, and I have a question about fuel. The fellow who sold me the bike said it doesn't run well on regular gas--he's been using premium. Now so far as I know a higher octane gas should just resist dieseling, and he said it just 'lacked power,' no knocking or anything. So, with this compression I should be able to switch back to regular, right? Anyone have any ideas what might have caused the problem or what i might do to fix it?

Dude is full of it. It's all in his head.

Higher octane fuel actually has less energy per gallon than lower octane fuel. You are correct, the only benefit to higher octane is that it resists self-ignition better.

There is no problem. Use regular gas.

[insaneman_12]

Read any manual it tells you to use 91. The higher the octane the cleaner you combustion chamber and carbs stay. I have been working on bikes for over 17 years and have proven this fact. People say it does not matter, but if you want to do less keep up on your bike run 91 octane. Plus better performance and even at the cost of gas you are still getting about 50-60 mpg. Plus what is $15 twice a week to have a better running bike.