from mine and others's experience, cr250s will detonate and fuck top ends if run on lower than 98
from mine and others's experience, cr250s will detonate and fuck top ends if run on lower than 98





on advice of a NZ 2T tuning guru, Im running half aviation gas and half 95 octane. I use the av gas for insurance against knock. It has been noted that most 2T's are marginal on our pump gas. Adding touluene (spelling??) at 5% mix was recommended to speed up the burn, but dont know where to source this. Anyone???
Cant beat the smell of av mixed with 2T!
On a 4T, I wouldnt run anything less than 98. Our fuels have the reputation for being crap, so I would pay an extra $2 to get the good stuff - cheap insurance against knock.



i run 91/av 50/50 in my 2 stroke race bikes, but i know alot of guys run 98 as well with no problems, you do have to be a bit more carefull with jetting and detonation on 98,
modern hi revving hi comopression (250/250F's) fourstrokes, 98 only,
Industrial Chemicals Ltd
Penrose
I know Chris Power only runs 91 in his CRF...
I run gull 98 in my 2T
put meths through some bread and them drink it and go blind![]()
MFSC lives on!
apparantly european fuels are far better quality than our shitty stuff,and my bike being from that neck of the woods is meant to run on98 or higher.so i mix av and 95 (our local servo's dont have 98)to get it about right, as some others have mentioned doing.i have found tho it wont idle on straight av gas???? and seems to run fine on straight 95 or even 91 if im really stuck for fuel.
I heard Gull is ethanol blend as well. Told this by a guy who swears black and blue it seized his chainsaw. I'm not convinced but playing it safe anyway!
Talking about av gas, mate reckons it's faster burning, I thought slower burn was better - more 'oomph' (for want of a better term).
I heard our fuel is pretty good quality. It's the American fuel that isn't too flash, something need to consider when trawling any US jetting threads.
Gull does have small amount of ethanol in there petrol. There was a website up with the list of what car/bikes couldn't use it and it was most bikes. So I wouldnt touch it. I normally run BP 98.
think the ethanol can eat some sorts of rubber
I think (but am not !00% sure)that it has a lower output for volume like lpg so you need more of it to make the same power , our old bikes used to go great when we put a little meths in the mix possibly didin't do them any good though
had a look on the gull site and its both there higher octane fuels are 10% ethanol
"The world is a strange sad place. Ride as often as possible and try not to think about it".
It all depends on how the motors compression and timing advance are designed. Also with 2/strokes shape of squish band. Just run what your maker states.
High octane just burns cooler/slower and so is used in motors 4/stroke wise with higher comp. Most modern vehicles are using optimised ignition loops so run higher octane. Hope it helps.
Just dont get your gas from the G.A.S store at Waitoki if your near woodhill, water in the tanks.... same prob that Caltex Dairy Flat had a few years back
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