Octane?

[lindhe]

For a 70cc 2-stroke engine - does the octane of the fuel have any impact on performance?

[90GTVert]

For the standard, run of the mill, 70cc kit you probably won't need anything above 87 octane if you set it up with the stock gaskets in the stock configuration. If you remove head and/or base gaskets to change port timing, or tighten up the squish clearance (which lowers the actual combustion chamber volume), or alter ignition timing with a CDI or by moving the stator/pickup you may end up needing a higher octane fuel. I would imagine some of the race oriented 70cc kits would also require the use of higher octane fuel. If you aren't hearing a ping or spark knock or noticing any signs of detonation you are probably fine with 87 octane. I use 92-93 octane in all of my scoots, but they all have tight squish clearance and/or advanced ignition timing.

[lindhe]

Thanks!

[WT100]

With my moderate 70cc i'm running High Octane exclusively. Through the tuning process as well. No problem with that i assume?

Or does it need to be a high compression set up?

[Goosey]

I just run High Octane as a rule. In 5 years I have yet to have a carborator issue. (knock on wood). Usually though I keep a gas can for the scoots, fill it when I do the car, so any sedamant would probably settle in the can before going into the scoot.

[WT100]

Good then I'll stick with the good stuff. Makes me feel better anyway

[feralsparky]

I run 87 in well... my 87 honda elite se50

And it runs great on either 87 or 92. I dont get much of a difference in performance.

[lshigham]

Mine hates anything below 97. I usually use 99, Shell V-Power.

[lshigham]

Oh, BTW, my 99 octane is about 95 in the states.