What fuel?

[racefactory]

Whatever petrol you use get bike jetted to suit. A guy a rides with runs his wr450 on half av gas half petrol. and has had jetted to suit runs mint my bike has been jetted for 91 I run 91 and can keep up. aswell as a 250 would

You can not jet a bike to take advantage of a higher octane, you can only alter the timing.

[shonofear]

i get 20-30ks more running BP 98' octane fuel and seems to stop these weird tick/click sounds when firing up the bike.
even felt more responsive through revs, even less vibrations on highway speeds (judging from feet vibrations on pegs, could be all in me head though)
but George from motorcycle doctors recommended not going near 98 for my Suzuki Bandit 250, told me a few stories of bikes carking it on highways running too high octane for older 250's.
but now that ive put 91 in, those weird tick noises have returned, sounds carby related.

[redhat]

Yeah Gull is good fuel, use it in my car but not the bike as the seals on the carbs MAY not like the ethenol

Correct, and Gull does have good fuel that is comparable to BP or Shell - but it is a bio-ethanol fuel (10%) in the 98 octane and it doesn't suit every vehicle manufacturer. We actually have pamphlets behind the counter that specify if your vehicle should run on the bio-ethanol or not. You can probably ask for the pamphlets at the Gull stations in Rotorua/Hamilton as well if anyone is curious. In my case, all Hyosung models apparently should not use it.

I fill up at BP.

[dblancer]

I keep to the midpoint with my bike. I run 95/96. As I always do with my cars.

I can't find a sure figure on my Jade, it is highish compression of 11, but it is also quite an old 250.
A friend told me once Japan runs 100, so if its import, run as high as can, if its domestic NZ new, it will be tuned for our lower octane fuels.

As previously mentioned, I'm never sure with a carb as its going to behave the same regardless of the fuel quality

I have talked to some people which have experienced rubbish performance out of their cars running 91, but mostly direct injection engines, turbos and imports.
I had an older style Galant, a friend put 98 in it to repay me for borrowing it and it ran like a new car... seemed to be alot more get up and go at the lights...

[explode64]

I run 95 or 98 in my RGV. never been keen enought to use 91. Both my Girl friend and her sister run 91 in their CBR250RR's. they have had heeps of issues with them when they run 95 or higher.