Fuel what do you do?
- Thread starter Bryce R
- Start date
some of those manuals recomend the octane for gas that is out side of the USA.. USA 91 is equivilant to 95 from other countrys... you should be fine.... if you really want to tho i know i seen those barrels of VP gas at the shops or just use booster. The good thing about the booster is it is a stabalizer tho so it helps your gas last and not go bad.
I know the difference in bikes/motors is significant however the Yamaha dealer and manual said to put the higher octane in my daughters 08 Raptor 80...I accidently put lower stuff in it (regular unleaded...octane???) and it ran just fine...in the desert, approx' 4000ft elev. (if that matters)
James
Staff member
What Trav said about the "out side of the US" is correct. The biggest thing you have to watch for is pre-detonation/knocking, if you're experiencing this then try a higher octane fuel.
Here's a little article on pre-detonation.
http://en.wikipedia.org/wiki/Engine_knocking
Here's a little article on pre-detonation.
http://en.wikipedia.org/wiki/Engine_knocking
There are two octane numbers and they are derived from different measurements. One is called "research octane" and the other "motor octane." In the US we average the two and put that on the pump. In most other places they just put the research octane number on the pump. In general the two numbers differ by about 8 points. The 91 we get here will have a research of about 95 and a motor of about 87. The number in you manual is a research number so the 91 should be OK. It will be right at the limit though.
You only need to boost the octane if you have pinging. Otherwise just ride.
The weird thing is the motor number is what we should be using. It is a better representation of how we use our engines. Not good for marketing though to promote a lower number.
You only need to boost the octane if you have pinging. Otherwise just ride.
The weird thing is the motor number is what we should be using. It is a better representation of how we use our engines. Not good for marketing though to promote a lower number.
Gotta say...I run everything on 87 octane from the Giant Eagle grocery store. I buy groceries, they give me a discount on gas. So I run everything on it. My weedwacker, lawnmower, truck, car, all my motorcycles, and I start my campfires with it. (With a whistleing bottle rocket from a distance! 
) I used better 94 Octane in my XR's, but it was a waste of money in terms of performance. I poured a gallon of 40:1 oil mixed 87 octane fuel into my bike one time because I was out, and it ran like a champ! I smell all these high end fuels at the track, but it doesn't seem to make them go faster or go fewer hours between expensive rebuilds! I call BS on octane unless you are over 11:1 compression!
You are wasting money and just being too anal about fuel below 11: 1. Tell me I'm wrong!
) I used better 94 Octane in my XR's, but it was a waste of money in terms of performance. I poured a gallon of 40:1 oil mixed 87 octane fuel into my bike one time because I was out, and it ran like a champ! I smell all these high end fuels at the track, but it doesn't seem to make them go faster or go fewer hours between expensive rebuilds! I call BS on octane unless you are over 11:1 compression! You are wasting money and just being too anal about fuel below 11: 1. Tell me I'm wrong!
James
Staff member
Not sure what your XR's are, but my 250F is 13.5:1 stock. Which is why I run 92/93, $0.20 isn't much, especially compared to 100 octane at $6 per gallon that some people run unnecessarily.I smell all these high end fuels at the track, but it doesn't seem to make them go faster or go fewer hours between expensive rebuilds! I call BS on octane unless you are over 11:1 compression!
I have no idea why this machine double posted...
I call BS on octane unless you are over 11:1 compression!
You're wrong.
My XR600 has 9.7:1 compression and it requires at least 91 octane while other engines have 12+:1 and only need 87. I got my 9:1 Mustang to ping on 87 a few times too. Steeper rear end gears helped a bit(food for thought). Compression ratio is only one of the many factors that determine an engine's octane requirements. Overall it is dictated by the design and application. Highly oxygenated gasolines are the only ones that produce more power in engines that are not already octane-limited because more fuel can be burned per combustion cycle. Octane is a like many things in life; the right amount is perfect, but too little is bad and too much isn't beneficial either. As an aside, it is also independent of a fuel's burn speed, flame temperature, and energy content.
I run a mix in my Husky's, 112 Sunoco Leaded and 91 Pump. 4:1 The lead helps the valve seats and I could care a less about price. I listen to the Husky Guru.