I`ve just been reading about the difference between unleade(95RON),and super unleaded(98RON).My sherco is supozed to run on 98RON.On the few occasions i1ve had problems,i post a message on this site and usually i get asked if i`m using the correct fuel.I always thought that the super unleaded ignited easier,but apparently not,in fact,quite the opposite.The RON factor is a measure of the fuels resistance to explode due to high compression(and cause pinking or pinging)rather than be ignited at the exact time by the spark.

I never knew this,but now i feel enlightened,and i thought i would post this message because i`m sure ther are riders out there who thought as i did...........or maybe not!!

HHHHMMMM,

Interesting, my view was the same as yours, I know SU is more refined and requires less oil as the base fuel is far better quality but didnt realise the ignition properties were less than that of standard fuel. Were did you get your info from ???

Just looked that up myself, did nt know either, but have noticed low octane fuel tends to knock. I try and use Shell V Power, 99 octane unleaded, works really well

shell V-power, with Motul 800 at 70:1, runs sweet as a dream.

http://en.wikipedia.org/wiki/Octane_rating

Check here

Okay here goes. Yes The lower the RON the easier it is to ignite. However this also means that in performance engines the tendancy is for "pre-ignition",(pinking), to take place. This is due to the high compressions used in these engines. Higher RON also has a higher calorific content. The result is that the fuel burns cleaner and longer because of the increased heat. This means it also produces more power for the amount of fuel burned. Because the fuel burns hotter then most of the carbon deposits associated with two-stroke's get burned off. Once this happens then the emissions are also cleaner because of the hotter burn. It has benefits all round.

We use Castrol XR77 which is for use with High Octane fuels.

Edited February 14, 200719 yr by Telecat

got to agree with the less carbon and no pinking with SU

stops the pinking single handed on my beta ( if fresh!)

and my cub loves the stuff

got to be worth the 5p a tankfull compared to all the other money i throw at the damn things..( thanks two and a half pence a trial, it's a real bargain)

Edited February 13, 200719 yr by totalshell

So,if i`m having problems starting the bike,assuming every thing else is as it should be,should i always use the correct grade of fuel,or use the normal unleaded???.

I know i should use the recomended 98ron,but is it going to start easier with the 95ron.I`m a tad confused now

Stick some Pro-Boost in the fuel, that will sort any problems you think you may have with poor fuel igniting. Personly I recommend the Shell V power and Motul pre mix as posted before.

Try avgas think thats the generic name for it. Its fuel for prop planes and its really high on the scale above 100 octane. Tried it and bike went like a works bike awesome. MX riders use it often and says it extends the life of the motors by 50% ?.

Avgas is good if you can get it easily, blag the guys at the airport you have a microlight and you should get away with it just hope they have nt got one and start asking awkward questions Use it 50/50 with superunleaded though, found it abit strong at 100%

yep you were right we mixed it 50:50 with normal unleaded and Motul syn oil only did it once but f*#k i made a diference.

Its great stuff to use even at

Ralph got me 50 litres of the Blue stuff today think he has about another 100 litres himself at that rate i will run out sometime next week and his 100 litres should last him untill 2018

I mix 112 racing fuel with pump gas, 80 to 1 on the oil and have never had a problem, unless I go up in the mountains then just 98 octane is good.