I've only recently purchased my first Bonneville and after my first ride I left the bike to cool down before covering it up, I left it for maybe half an hour went outside and checked the exhaust pipes fine but when I put my hand on the engine cases I was surprised that they were still so hot I don't think I could have kept my hand on them. so the question is is this normal for the rest of the engine to get so hot, I've never noticed any of the other bikes I've had get that hot thanks.
There’s a lot of HOT OIL in the engine and after you’ve stopped riding it means that there’s no air flow over the engine to help dissipate the heat It’ll now radiate the heat through the casings I wouldn’t worry too much as long as you’ve got enough oil of the right grade in it
Residual heat? Yes, as my other two bikes are water cooled, there is only one place our Cat goes when I come home on the Thruxton, no sooner than I park it up in the garage the cat goes and sits underneath. She never does that with the others.
The engine is not much different to the thermal mass of a log burner. It is a big lump of metal with a gallon of oil that was all about 125C when you switched off - appreciably hotter than a kettle. Cars come with a tin jacket that acts as a heat shield that we usually only open when they are cool. Can’t think why!
If air-cooled - normal. Although I don't cover mine in riding season, you may want to throw a floor fan on it. Clutch cover really holds the heat for awhile. I do that if I want to work on it between rides. I even cut over to 20W-50 oil due to such heat.
If you could touch the head and hold your hand on it, that registers less than 50C in my hand to mind measure. I used this a lot in evaluating electric motors. You bike probably operates at around 100C in warm weather, which is the same as your cuppa out of the kettle. Burn quality, for sure. In the end, your encounter is not very hot. However, maybe hot enough to deform a cover or leave melted cover material on your exhaust (been there). I always wait several hours before covering.
