Would hot weather make scooter run richer?

[ove]

Would all this hot weather make a lambretta run richer? I've often heard people talk about scooters running lean in cold weather.
Opinions greatly appreciated folks.
ove.

[carlos fandango]

Yes it can, warm air is less dense than cold air, warm air expands , so a cubic meter of warm air has less oxygen than cooler air. Altitude also has an affect, the higher up you go the air is also less dense , so less oxygen , making you run richer.

[mick1]

So (if you didn't adjust you carb/timing) would your cylinder run cooler or hotter........?

[Chris in Margate]

Running richer is cooler and running weker is hotter.

[Jazzy]

Petrol Also expands with heat.
That's why airlines and f1 teams measure fuel by weight.
And one group 4 racer kept his petrol in a fridge prior to races and insulated his tank (allegedly).

So rough and ready logic would dictate, you will run poorly as there's less bang to volumes but the ambient air is hotter so forced air cooling will be less effiecent. So you will show higher cht temps.

Could be wrong ,

[nelson pk]

Definitely. I would expect a two stroke to run richer in hot weather and leaner in cold weather.
Racers jet to the conditions for optimum performance but on a road bike you have a compromise on jetting for all round conditions.