1980 gs750E. Power and lights, but no starter, no Ignition

[Wump]

Hey guys,
I've got a 1980 GS750E that I've had for about a year now.
Couple days back I went out for a ride, stopped for a minute, then when I went to start up again, the starter did nothing. No click, no dimming of lights, nothing. I bump started and carried on with my day.

A couple hours later I hopped back on and again no starter. But this time I couldn't even bump start. I rode two blocks down hill with nothing. Took off the tank, side covers and headlight, fiddled with wires but couldn't find any loose. Put the bike back together and it somehow bump started fine...

Now today I'm back at square 2. Starter is still completely not responsive, and won't bump start.
Battery is charged and good. Lights are strong. (I have noticed that the headlight gets brighter at higher RPMs if that is is a telltale sign of anything.)

Any tips as to which wires I need to check first?

Thanks!
Phil

 

[crapwacker]

I had a problem with the clutch interlock on my 79. You could check to see if that switch ti functioning correctly. My connectors, in the headlight, allowed me to bypass the switch, as I believe there is a broken wire in my harness.

 

[bighamms]

@ wump....what's a bump start and how's it done?

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. Wump,

I tell you what, these old bikes love clean electrical connections and clean grounds. Take the time to check and clean every electrical connection and ground on the entire wiring harness, from the headlight bucket to the tail light, including the fuse box, the ignition switch, that big fat ground cable that connects the negative battery terminal to the bottom of the engine, everything. But for your issue, I would especially check the connections and ground to the starter solenoid. Did somebody say "mega-welcome"? Yes! I did!

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

 

[BassCliff]

@ wump....what's a bump start and how's it done?

Hi,

That's when you turn on the ignition, get it rolling, put it in gear, and pop the clutch to make the rear wheel get the motor turning. It's like a "push start".


Thank you for your indulgence,

BassCliff

 

[Wump]

Thx for the welcome

Thx for the welcome

@ wump....what's a bump start and how's it done?

Thanks for the welcome and the pointers!

As for the bump start, it is indeed just popping the clutch. We've always called it a "bump" start because by dropping yourself onto the seat, or "bumping" on it, you get better traction right as you let out the clutch.

So far no luck with finding the electrical fault... Many more wires to check.

Phil

 

[Guest]

Recently I had a battery that showed good voltage but it had an internal short that showed it's head every time I tried to start it.

 

[Wump]

GS1100GK,

I appreciate the thought process there. It sounds plausible that the wiring in the kill switch is buggered. I'll take that apart next when I get back at it. I've had it on the back-burner for the last week or so.
This gives me something new to try.

Thanks,

Phil

 

[rmathew313]

hey wump i was just wondering if you ever figured out what wrong with the bike... my bike that i just got was told has the same problem as you do... mines a 82 gs450t... so maybe you could help me out.. thanks

 

[Wump]

Continuing frustration update

Continuing frustration update

I cleaned every ground, checked continuity to the starter, and took random pieces apart following wires, but hadn't found anything really out of sorts.
While I had everything apart, I tried the starter.
It worked!

So I put back pieces to a point that I could get the air filter back in, hit the starter again and... nothing.
Back to square one.
I'm baffled. I think this means it has to be a connection that is loose. I hope.

I have no idea where this loose/shorting wire is. any tips on how to track it down?

Phil

p.s. checked the kill switch. It works. unfortunately. That would have been nice if it didn't.

 

[posplayr]

I cleaned every ground, checked continuity to the starter, and took random pieces apart following wires, but hadn't found anything really out of sorts.
While I had everything apart, I tried the starter.
It worked!

So I put back pieces to a point that I could get the air filter back in, hit the starter again and... nothing.
Back to square one.
I'm baffled. I think this means it has to be a connection that is loose. I hope.

I have no idea where this loose/shorting wire is. any tips on how to track it down?

Phil

p.s. checked the kill switch. It works. unfortunately. That would have been nice if it didn't.

put a volt meter on the yellow green (Y/G) wire that attaches to the solenoid. See if you are getting 12V when you hit the start button with kill switch activated.

If you do the switch is OK.

Next make sure the solenoid is grounded.

If it still doesnt work, turn off the key and measure the resistance to ground from the Y/G. If it is open sounds like the solenoid is bad.

With a good solenoid it should crank the nmake sure you have spark

 

[jwhelan65]

See what kind of voltage you are getting from the battery when you hit the starter, Chef maybe right could be as simple as the battery. I had what seemed to be a good battery on my 700, in the end a new one cured all my strange starting issues.

 

[Wump]

Solved!!

Solved!!

Hey guys,

Thanks for all of your advice! I now have exceptionally clean contacts, have learned how (and how NOT) to test voltage, and have somewhat figured out how all the wiring works on my bike.

Alas, the problem was: a broken fuse. Not really burnt out, more broken. When I shook the fuse a bit I could get it to reconnect and work. I figure when I did my bump starts previously, I bumped the fuse "back together" and then it worked fine until my next bump start attempts bumped it back apart.
Jumping the fuse contacts with a screwdriver and the bike fires up no problem.
I'm not sure what would have caused the fuse to break initially, but I'll figure that out in due time. Perhaps my clean grounds will solve that too.

Again thanks for your advice guys!

Phil