Fuel requirement, and noise?

[ccemn1]

I just purchased a 2018 Xtown 300-I, It came with a full fuel tank, but I heard what at first I thought was engine ping, so when the tank was near empty, I filled it with hi test, premium fuel. It stall makes the same noise, which I figure now is coming from the CVT? I checked both oil and the Trans fluid and that's also up to snuff.
The manual lists the fuel requirement in some sort of European formula. Any Yanks in here that can guide me on fuel requirement and maybe give me a clue what the noise might be?
The engine is muffled so well, it might just be so quiet that the Trans is all I can hear. A little alarming though, because it's a clatter, almost exactly like engine ping.
Thanks in advance.

[Stig / Major Tom]

Hello,
Are you new to scooters?
The noise might be the clatter of the roller weights in the CVT.
If unfamiliar with scooter noises - that can seem worrisome.
Stig

[CROSSBOLT]

This fuel requirement discussion has graced this forum at least a hundred times since 2009 when I first joined. Kymco has been unable to get it right except in the placards in the met-in tubs where it usually says 87 (R+M/2).

[MJR]

Good reading. https://en.m.wikipedia.org/wiki/Octane_rating

[ccemn1]

Thanks guys. I think Stig is right. The noise seems to be coming from behind the engine. And, I guess I can use regular gas?
Funny thing, I had a Ducati that supposedly required premium gas. While on the Dyno, remapping a Dynojet Power Commander, we tried it with both premium AND mid Grade gas, and it actually made more HP on the Mid Grade. Same day, same bike, same Temp, everything.
Of the over 40 Motos I've had, only 3 were Harleys, but I thought this picture was funny.

[CROSSBOLT]

I think we are on to something here!

[MJR]

Funny thing, I had a Ducati that supposedly required premium gas. While on the Dyno, remapping a Dynojet Power Commander, we tried it with both premium AND mid Grade gas, and it actually made more HP on the Mid Grade.

Not surprising as lower octane fuel is more volatile and burns better. Most people don't understand what a octane rating is and assume higher is better.

Octane rating is a measure of a fuel's ability to resist ‘knock’. The recommended octane rating for most vehicles is usually octane 87, but be sure to check your vehicle owner’s manual. Ordinarily, a vehicle will not benefit from using an octane higher than recommended in the owner’s manual.

[CROSSBOLT]

Bless you, MJR! There are some that will argue with you on that as you well know!

[ccemn1]

Obviously true. Because even though the Ducati owner's manual clearly stated to use Hi Test fuel, it was making more HP on the mid grade.
There used to be a formula for compression ratio to octane rating, but I don't remember.
What was throwing me off, was the clatter, knocking, perceived ping, that I mistakenly attributed to engine noise.
To answer Stig's original question, I'm not new to scooters, Currently also own two Super 8 150's, the main reason I bought the Xtown. The 150's have a louder exhaust, and/or quieter CVT, because I've never heard noises like these coming from either of them?

[Viper254]

Thanks for the link MJR. I feel educated!

Fuel's all 95/97 octane here in the UK.