Ultra 94 in the tank over winter

[toysareforboys]

Somebody once told me it's a bad idea to leave high octance fuel over the winter(Im pretty sure person who told me was making a point about Sunoco/Petro's Ultra 94). He never did provide a reason as to why this was. Can anyone shed light on this? My 07 zzr600 states right on the tank 91 and over, so I figure by putting the 94 in all the time I was doin the bike a favor.

They were referring to the ethanol in the fuel, not really the octane rating. Only Ultramar 91 and Shell 91 contain no ethanol, every other grade and brand DOES!

You do NOT want to store your bike over the winter with Ethanol based fuel. It degrades quickly and leaves behind a hard varnish that will make your injectors stick, clog the nozzles, etc. Once I stopped using Sunoco 94 over the winter and started using Shell 91, NO PROBLEMS! woot

This is correct. Further to that, octane does not make hp. Case in point, mr12, generally regarded as a very powerful race fuel, is rated at 87 octane. Certain race fuels will do damage if left in the tank for even a few days. This does not apply to pump. Check vp fuels web-site for mor fuel info.

Yikes! I didn't know MR12 was only 87 octane!!! I better back off the timing advance when I give her a rip

-Jamie M.

[Flywheel]

I know it's an endless debate, but before I realized the OM suggested 91, I was using the cheapest swill. Can't imagine there wasn't ethanol in it. Never got around to winterizing the scoot since I was working on it. Didn't gas up for three months. Started twice for oil/coolant changes. Forgot about it. Started up with no problems in the Spring, even with a non-tended battery.

Maybe some blends pair the ethanol with another additive that causes problems when left to sit? My tank is some sort of plastic and the Burger is fuel-injected.