B50 Hot electrical box

[Servodyne]

Hello all,
After putting on a few miles on my B50 SS after a rebuild, I've come to notice that the electrical box gets quite hot on a good run. I know it's quite close to the cylinder head and exhaust pipe, but I wouldn't expect it to get so hot. I'm just wondering if "they all do that Sir" or I should be looking at something overheating inside, such as coil or zenor.
Cheers
Jim

[neil1964]

What is in the box? Presume rectifier, ignition pack for EI, coil??
A healthy Zener diode needs a heat sink to dump the extra juice above (iirc) 13.5v on one of these assuming your alternator is in good order. 
Ideally it should be mounted on the bottom yoke on a bracket under the headlight with a little heat transfer paste between zener and aluminium 'cone' to keep it cool.

[Servodyne]

Aye, it's got the lot in it, coil, Zener, Rectifier, flasher unit and now the Wassell EI.
I don't really want to ditch the originality, but just wanted to know if they normally run hot given the location.
Cheers

[Jim S]

Hi Servodyne

I took my 1972 B50T for a half hour run today, then shut it down and took some temperature measurements on the outside surfaces of the electrical box with a laser thermometer. Following are the measurements:

Underside - 50C
Side Towards Front - 26C
Side Towards Rear - 40C
Top - 30C
Ambient Temperature - 20C

I was riding slow with no lights. I have a standard bike with pretty much original components.

I don't consider the above temperatures as excessive given the location of the box. All surfaces were not too hot to touch.

Jim

[Servodyne]

Hi Jim
Thanks for doing such a detailed analysis of the temperatures of your electrical box. Mine's probably the same as yours so I'll stop worrying.
Many thanks
Jim