1980 GS750 charging problem

[Anonymous]

Any advice appreciated guys:

I've rescued a GS750L from imminent retirement and spent a lot of time and effort getting her back on the road. It's involved a little electrical work, and lots of mechanical/body work. She now looks and sounds sweet. Unfortunately her charging system seems to have preferred the retirement option.

When taking the bike out for a run, after an hour or so the battery will struggle to restart the bike. I've taken the battery off and placed it on a charger/monitor which comes back saying its fine (although it is old). If I leave the battery on the bike for a few days it doesn't seem to drain.

Anyone know the procedure for testing the regulator to see firstly if its working properly? Any other possibilities?

Thanks.

[Anonymous]

Ah, just found the stator pages section.....

Sorry.

[focus frenzy]

is the problem happening if you try to restart the bike right after riding for a hour, or does the bike set for a few minutes then struggles to restart?
have you carried a meter along and checked what the battery voltage is, right after stopping?

[Anonymous]

Time doesn't seem to make any difference. The first time I got this was the time taken to open the garage door and turn the alarm off, but it happens if left for hours or seconds too.

I did a quick test last night from the stator pages. On idle, battery voltage was 12.7. Revved to 5k it rose to 16.3. However I couldn't do the further RR red wire testing as there were 3 sealed red RR wires. I'm not sure if this is the correct RR so tonight I'm going to get all the details wrote down and post again to see if one of you guys can help. I'm also going to get a new battery as this one has a date mark of May 98. 5 years is a long time for a battery.

Thanks.

[Anonymous]

I have a similar problem on my 79 850G. Only mine happens when the bike sits for a day or two. It will still kick start but not with the electric. It has a brand new bat. ???

[Anonymous]

Its the Regulator/Rectifier.

It sounds like you have a bad Regulator/Rectifier. If the volts are running away like that the stator is still alive just out of contol. Take the R/R off, and order a new one. While its on the way you can test the Stator + clean up any contacts you can find. Don't run the motor any more than you have to for the test. It will cook your battery.... You may have noticed already that your battery level keeps droping.

[Anonymous]

Cheers guys

Turned out to be a 'faulty' RR unit. I say faulty because it's not supposed to be on a Suzuki, coming from a CB550 NightHawk. :? It might work, on a NightHawk. I got hold of a proper Suzuki one from a breaker and hey presto, voltage what its supposed to be.

Thanks.