Octane should be the main difference. A 2-stroke complicates matters because a small amount of oil is being burned. Oil reduces octane. Aside from that, the temperature of the engine, the head, plug tip, etc has an effect and certanly will change as you run. By 45 hrs you mean the fuel is 45 hours old? Ethanol in fuel increases anti-knock but also steals power since it converts to less when burned. It might be possible for some ethanol to evaporate in the heat, but how much, and is it a factor?
Maybe you are very close to the type of detonation that's bad enough to hear and some small factor is pushing it over the line.
I don't have much modern 2-stroke experience but do have old-style non-computerized hot rod car experience and there were times when the so called premium fuel detonated. The fuel formula changes from summer to winter, who knows what they do to it. In the summer, it was best to buy VP or other consistent fuel a couple octane points higher than needed to put an end to detonation.
One thing that comes to mind if your bike has a seperate reservoir for the 2 stroke oil is whether the delivery is constant. How many hours of riding does the reservoir hold? Does it deliver consistently until it's empty?
I can only suggest the best fuel & a little more octane if you are racing and aso a cooler plug, but not sure how that would affect fouling in a 2 stroke. Hopefully someone will comment on this but there isn't much to go on.
Edited by Xray Wombat (09/23/19 08:59 AM)
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