Fuel- compression ratio

[Abennett]

Building my sons 70. Ordered a new complete top end that has 13.8 compression ratio, I had no idea what the stock ratio was, so my question is 93 unleaded or 110 racing fuel? Thanks

It might run on 93 pump gas, Some do some don't. But 110 race will be lots better. My sons has 210 psi and it will run on pump gas but is a totally diffrent quad win we mix 110 50.1 with Ames Dominator. Give them both a try and see..

[mmsoup]

If you are running a high revving European Two Stroke, save yourself some heartache and run straight C12 mixed with the quality oil of your choice. I burnt way too many motors up running 1/2 and 1/2 over the past few years and once we went to straight Race gas, we never burnt another motor up.

On a high performance four stroke at 13.8:1 it would be straight race gas as well. Anything above 12;1 needs higher octane to avoid detonation

[Abennett]

It is a 2 stroke, thinking Sunoco 110, what's your guys on yamalube R2 thanks

Trick 108 or Sunoco 110 and mixed with Ames Interceptor or Dominator 2cycle oil at 50.1 is what I run in all my sons minis and dirt bike. All are built and run flawless!!! They will run on 92 but like s-h-i-t.

[fomospede]

correct octne is crucial you can throw the wrong rating and fry the motor with to low it will run to hot and burn up the topend
run to high of an octane and tuning is an issue as the mix will be cold because it takes longer to burn
are build calls exactly 102 so we mix 112 with ethanol free 93 at 50/50
i personally would ask the builder
or call hetrick or hotquads these guys will be glad to help
and have way more experience!
we run super m maxima 45-1
smokes a little and never has scuff marks and is readily available

[Abennett]

I thought these little bikes run a 32-1 mix was I just miss informed?

[fomospede]

if you where to run per the manufacturers suggestion sure
but the back of the pack theres alot of dust!!!!!!!!

[chunky0071]

Ok let me put a little on this compression does effect what octane you need but it is not the only factor for selecting octane. RPM's is another factor that is rarely look at when selecting fuel. For a say 12:1 compression you may only need 100 octane if you keep it below 8000 rpm's. Same compression that runs mostly above 7000 needs more octane say 112.

112 octane leaded race fuel designed for competition engines routinely operating over 7000 rpm. 112 octanes fast burn speed also makes it a popular choice for 2-stroke applications!!!

[mmsoup]

I had a lot of ash from the Sunoco

Yamalube is just fine
Dominator is good
We run Belray MC-1
Klotz is good
etc etc
Stay away from the castor based Maximas on cold days

Pay the extra and burn the VP C12 nothing is better. If you want to lower the octane and speed the burn up, buy a can of the VP 100 octane and mix down to your desired octane.

There are many opinions on this subject, this is only mine but comes from hard won experience.

[Abennett]

I called Gary at G Force and he told me to run around 100 octain so I went with Sunoco 110 and 93 mixed 32 to 1 R2 yamalube , bike runs great next season we will be adding matching exhaust and carb for the Molassi cylinder and upgraded cvt and electronics,

[fomospede]

Stay away from ethanol

[Abennett]

Originally posted by fomospede
Stay away from ethanol oh yea not going there, NASCAR can have that **** lol