GS550E 1978 - Electrical dead short

[starfield]

My son has been using my 1978 GS550EC for a few weeks with no serious problems. Last night he switched on the ignition - everything appeared normal except starter ground very slowly then all the warning lights went out. Thereafter totally dead. Picked it up this morning and found main fuse blown. Put a 21w bulb in its place and switched on ignition, bulb glowing like a good'un so obviously a dead short somewhere.

Son took bike of my hands as soon as I bought it so have little or no practical experience of this bike so far. Would appreciate any pointers as to where to start looking for the short. Is there a known weakness in the GS electrics that causes this sort of thing?

Live in the UK, near Bath by the way

Am avidly studying the wiring diagram at present

Thanks

Peter

[duaneage]

Unplug the red lead from the Regulator rectifier assemblies that feeds the bike and try it again.

The regulator could be shorting out.
You may have a 2 piece charging system, that can be replaced by the Honda Kit I offer. The RR is capable of causing this problem since it directly feeds the battery and is known to fail. I've seen a RR that would short the bike as soon as voltage from the stator entered the regulator.

[starfield]

Short Fixed

Thank you for suggestions about the reg. This was my initial reaction as well but in fact the short was nothing to do with the charging system and was a bit elusive to find.

Turned out to be a poor assembly of the engine stop and starter button wiring in the twist grip with one of the wires trapped under the plate which secures the wires. It took 32 years but eventually the insulation fretted through and touched earth. Took me 3 hours of systematically following every wire and connection. The breakthrough came I found that the short did not occur if the kill switch was in the off position.

Anyway all fixed and I treated the old girl to an oil change and filter whilst she was back in my garage.

Many thanks.

Peter