I ran my 79 CB650 today and as it had been sitting without running for a while I let it warm up and then got it to idle at about 1400 rpm.
As I had been mucking around and failing to get the bike to respond recently the battery had died so I hooked up a spare car battery I had and used jumper cables to start bike.
After maybe 10 minutes my partner said she could see smoke coming from the area just behind the tank.
On a 79 this is the hollow where the wiring from the alternator and motor attach to the rectifier and regulator.
The wiring and rectifier/regulator were both quite hot, the regulator has cooling fins so maybe (this is a question) it is not designed to idle for such long periods without having cooling air moving over it?
At this point I still had the car battery attached (something I had overlooked as I would normally unhook a jumper battery once the vehicle started) so maybe this caused the heating?
As the area where heat occured is directly under the riders seat and thereby the family jewels I can't see the Japanese allowing this.
As a bonus there was some old oil residue sitting just under the rectifier and regulator, maybe this was warming enough to smoke?
And I always wondered how motorbikes caught fire!!!!
So big question, should these parts heat up under normal conditions?