1980 GS1000g - TSCU and Charging Questions

[CBJoe]

Hello Folks,

I picked up an '80 GS1000g from a guy at work for $200 last fall which was not running. Electrics were all dead. I've since pulled and stripped the harness and replaced, re-done, most of the connections. vintageconnections.com was a lifesaver here.

Anyway, I just slung the harness over the bike and plugged everything in to test it out and the bike started right up and sounded great!

However, something was loading down the fuse for the circuit used by the turn signals and brake switches. Fuse would blow after 3-4minutes of being on. I unplugged the TSCU and all seems to be good.

So my TSCU question:

- with the TSCU removed, all the flashers and brake lights work properly. Is there any reason I cant leave this off? Just making sure there isn't some hidden function I don't know about. I could care less about self-cancelling turn signals.....none of my other bikes has that function

Now my Charging Question:

- At idle (1500rpms) i'm getting 14.5V across the battery. This seems high to me at idle. i'm used to around 13V at idle and then increasing to 14.5 ish volts as the rpm's increase.

Thanks for the input. I'll post some pictures of the bike and project in another thread later. Just looking for some input on this now. If you want to see the bike, you can check it out here http://forums.sohc4.net/index.php?topic=132594.0

Cheers, Joe

 

[posplayr]

Perform Quick test in my signature and report the results.

 

[CBJoe]

Hello, Those steps are which I did earlier. Sorry, should have posted the values. Off-12.8V, ON-12.5V, Idle-14.5V, > Idle-14.5V

Just seems odd to me that R/R seems to be charging at idle.

At this point I wont be able to perform any more tests for a while (other than bench tests). I re-pulled the harness to finish working on it and re-wrap. Also, pulled the Carbs as they flooded due to leaky floats. Just going to do a basic disassemble and take them to work to ultrasonic and blow the passages out.

Thanks for input on the charging

Cheers, Joe

 

[posplayr]

Who knows what is going on? Given only 4 of 6 measurements I hate to even hazard a wild ass guess.

 

[CBJoe]

Who knows what is going on? Given only 4 of 6 measurements I hate to even hazard a wild ass guess.

Thanks

I suppose I didn't spell out...Answers to number 3, 4, and 5 were the same. 14.4V - 14.6V at 1500, 2500, and 5000 rpm. Over 5000 and the voltage started to drop. Sorry for not having the answer to number 6, but lets assume that it was as the test says (slightly higher than initial power on).

1.) key off................12.8V

2.) key on (but not cranking with lights for 10 sec).....12.5V

3.) at idle (1500 rpm).....14.5V

4.) at 2500 rpm ...14.5V

5.) at 5000 rpm.....14.5V (voltage drops off a bit above 5000rpm)

6.) key off.....?

I'll be able to check again in the future, but I'm curious on your (and others) experience with these bikes and whether 14.5V at idle this is abnormal or not. To me this is abnormal unless the GS1000g's charging system is that much different than my Honda CB650, my Yamaha XS750, and my Triumph Bonneville.

Regards, Joe

 

[posplayr]

Well again without the numbers at each voltage it is had to tell much except that you appear to be charging. Lower your idle speed enough and the voltage will drop.

Please bear in mind there is a reason, that I ask for all 6 numbers. There are subtle hints about what is going on that can be deduced from the small voltage changes that occur under changes in RPM. You answers repeatedly mask that information.

Proceed to Revised Phase A tests and measure your voltage drops.

 

[Nessism]

14.5 V @ 5000 rpm. Can't be too messed up.

 

[posplayr]

14.5 V @ 5000 rpm. Can't be too messed up.

You are correct, although I would be a little concerned with over charging. Being at 14.5v almost consistently across the board, is higher than normal. The 14.5 at 1500 is probably explainable by high idle. If the voltage drops are low then he is good to go.

 

[Nessism]

Maybe one of those "extra windings" stators is installed?

 

[CBJoe]

Maybe one of those "extra windings" stators is installed?

I would be ok with that!

I'm good on the charging question for now. Obviously it's charging, but I will double-check the idle and see what the voltage does at rpm's < 1500 when I get everything back together.

Can someone clarify this for me?

- with the TSCU removed, all the flashers and brake lights work properly. Is there any reason I cant leave this off? Just making sure there isn't some hidden function I don't know about. I could care less about self-cancelling turn signals.....none of my other bikes has that function

I see posts about "mods to remove the TSCU or change it out, but my bike appears to function just fine without it. Blinkers and brakes work just fine with it unplugged (other than making it a manual operation of course).

As a little extra info, here's the bike as I picked it up and some of the bad wiring I re-worked..





Harness Stripped for some working...







Some bad connectors











And to prove it ran (before I pulled the carbs)




Cheers, Joe