1979 GS750e high electrical load issues

[gearheadE30]

Hey all, my first post here, lots of good info! One of the few things I couldn't find through searching was an explanation for this issue, though.

I just bought a 1979 GS750E. Wonderful bike, I must say, especially coming from a 1980 Honda CM400T. Riding it back from work today, I noticed that if I turn off the lights, the rpms come up a good 200 revs. I know that the lights take a good bit of power and will load the alternator/generator more, but this seems excessive to me. My first suspects are the grounds for the harness, and I've seen reference to there being a few that should really be moved to a better location. Any advice on what to check or change just to make sure the electrical system stays reliable and I'm not putting excessive load on it?

 

[tom203]

Hey all, my first post here, lots of good info! One of the few things I couldn't find through searching was an explanation for this issue, though.

I just bought a 1979 GS750E. Wonderful bike, I must say, especially coming from a 1980 Honda CM400T. Riding it back from work today, I noticed that if I turn off the lights, the rpms come up a good 200 revs. I know that the lights take a good bit of power and will load the alternator/generator more, but this seems excessive to me.

Excessive indeed.Is your warm idle rpm too low? 1000 rpm should be able to cope with headlight no problem - standard headlight takes about 60 watts and is fed by its own 10 amp fuse. Break out the multimeter and see how your charging system behaves as you turn light on/off.

 

[posplayr]

Well come aboard, load will affect RPM but not sure you have a problems unless you go through the electrical with a few tests.


see GS CHARGING_SYSTEM_HEALTH

 

[gearheadE30]

Okay, cool. The bike has an H4 light on it too, so that likely will increase load as well. The bike idles at 1100 revs, although I need to find a place to buy new carb boots (the ones between the carbs and the engine) because I've got a bit of a hanging idle. I'll dig into it this weekend when classes finish up for the week.

 

[Nessism]

Most likely due to drawing false air though the intake. The bigger issue is lean running which can damage the engine.

 

[gearheadE30]

Yeah, cylinders 2 and 3 are running a fair amount leaner than the outer two; I just have to find a source for the boots and the time to install them, hah. And the time to check the valves while I'm in there, I suppose.