Not talking about sunny sunday rides vs rain-soaked outings. I just notice that when the temperature rises my bikes drops, in performance. We know that colder (denser) fuel gives out better engine performance but: how substantial (noticeable) can that be? I mean, on very cold mornings my bike feels VERY grunty, ie, it pulls easily in 2nd and also 3rd gear, today: it just felt sluggish. Now, just by coincidence, it didn’t feel like that since I last filled up in Sainsbury’s/Tesco (which i incidentally did yesterday), I know someone commented on (never) filling up in thus places so, could there be a link, and therefore sod (partially) the weather?
After a fill up I always used to notice slightly better performance - i put it down to more pressure being exerted on the fuel going to the carb as there was a lot of fuel above it - it may have also made the fuel beneath slightly denser.
My current bike is fuel injected and its performance is always the same regardless of how much is in the tank - i havent ridden her yet in a heatwave so watch this space!
Yup, cold humid air (misty cold) will do it.
The difference can be as high as 5% ish which is why performance engine manufacturers once experimented with water mist injection. (If Porche can’t get it to work, forget that.)
Supermarket fuel? Tesco, part bio, premium lead free is reckoned to be the best pump fuel on the market. But it costs.
Your choice.
Oldguy.