What does G91 stand for under the gastank cap (see pic)?

[bioman_imp]

Is it a recommendation for the ideal octane level percentage?

[Lord Popgun]

Mine says the same thing so it is not for octane. 87 specified for US CBs.

[peterbaron]

So it is for our Canadian bikes as well

[Cormanus]

Mine says the same thing and, even though Honda recommends 91 octane fuel in Australia, I suspect it's more likely to be a part number.

[jtopiso_imp]

Mine says the same thing so it is not for octane. 87 specified for US CBs.

Can be "91 octane RON", which is the standard in Europe (and I assume most parts except the US)

91 RON can be 87 octane (US)

[GoldOxide_imp]

Honda would likely put a sticky label on the fuel tank if the CB1100 required a performance grade of gasoline and not void warranty.

"G91" is a subassembly number.

[Tev62]

Apart from that your fuel looks dead murky

[Gone in 60]

One of the first things I noticed when I was looking at my CB was that the gas cap was the same as my old Nighthawk 750.

Can someone here with a Nighthawk see if their gas cap has the same stamping?

[bioman_imp]

Apart from that your fuel looks dead murky

Haha, yes, it looks very oddly coloured indeed in this picture. But I can assure you that in real life, all is well.