1980 GS450L not starting

[thecreature8]

I'm having some trouble getting my 450 to start and I've reached the limits of my knowledge for where to look.

To provide a little backstory, I removed the fuel tank at the end of 2023 to clean some of the rust out of it and coat the inside and ended up repainting the exterior...a project that admittedly got away from me and took a few months. When I first reinstalled it, I would just get a click when I tried to start it using the start button. Jumping the connection on the solenoid would sometimes get it to crank slightly but not enough for it to try to start.

This weekend I replaced the battery (the old one had been in there since I bought it around 2018 so it probably needed to be replaced anyway), put fresh gas in it, and replaced the spark plugs. There was some gunk in the lines from the petcock so I cleaned those out. Now the starter button does not seem to do anything. I did test the connection behind the headlamp and when the button is pushed, the correct contact is made there but no dice otherwise. When I jump the connections on the starter solenoid, it cranks and sounds like it starts to rev up but then dies immediately, usually accompanied by white smoke from the exhaust (which is not unusual when starting it after a long period of time in the time that I've owned it). It does this pretty reliably but will not run. The choke is on (it won't start at all if it is off).

When I put a meter on the terminals of the solenoid, I get a short, which I have a limited understanding of but I thought that was supposed to be an open circuit unless the starter is pressed. The fuse off the battery appears to be fine.

I'm not sure if the issue is electrical but with the mess of wires in there and my limited experience reading wiring diagrams, I'm having a hard time figuring out where to look. Bad solenoid? I'm not sure if it is possibly related or a separate issue but when I engage the front or rear brakes, the brake light does not illuminate. Any idea where I should be looking? Thanks!

[ukjules]

q)
did it work before tank removal ? what was the status pre your tank project ?
If it did it has to be a loose , broken connection from tank removal.

Have you tried a new solenoid ? or tested it. Many tests on you tube to check that. They are very cheap.

As for starting the bike - jumping it starting a bike from a long lay off can be difficult but if yours ran fine pre tank project it should not be that hard.

what were the plugs like ? wet with petrol ?

but you say gunk in the fuel lines. that ain't gonna help and points to a barn find or residue from your spraying . let's hope all that not got into the carbs.

gota be sure all settings right , plugs , timing , mixture , air filter etc etc ....

two issues :
- starter doesn't work
- won't start but turns over

[Rob S.]

...cranks and sounds like it starts to rev up...

???

You said the fuel lines were gunked but you "cleaned" them? How about replacing them?

[Rijko]

First thing for me would be to solve the starter solenoid issue, so the bike will at least crank.
One issue at a time ...

There should be a green/yellow wire on the solenoid, with a bullet connector.
Disconnect that.
Press the bullet connector to the solenoid terminal that has the connection to the battery.
Contact does not need to be on for this.
Does that make the bike crank ?

Also, switch on contact and kill switch : green/yellow wire still disconnected.
Now press the start button and measure what voltage is arriving at the female/loom side connector of that green/yellow wire.
If that is around 10V or lower, you may see ignition issues in my experience.

When I put a meter on the terminals of the solenoid, I get a short, which I have a limited understanding of but I thought that was supposed to be an open circuit unless the starter is pressed.

correct, but ...

When I jump the connections on the starter solenoid, it cranks and sounds like it starts to rev up but then dies immediately.

If there were a short, the bike would be cranking all the time.
Maybe you are using a beeper to measure this ?

[thecreature8]

q)
did it work before tank removal ? what was the status pre your tank project ?
If it did it has to be a loose , broken connection from tank removal.

Have you tried a new solenoid ? or tested it. Many tests on you tube to check that. They are very cheap.

As for starting the bike - jumping it starting a bike from a long lay off can be difficult but if yours ran fine pre tank project it should not be that hard.

what were the plugs like ? wet with petrol ?

but you say gunk in the fuel lines. that ain't gonna help and points to a barn find or residue from your spraying . let's hope all that not got into the carbs.

gota be sure all settings right , plugs , timing , mixture , air filter etc etc ....

two issues :
- starter doesn't work
- won't start but turns over

It wasn't 100% before the tank project but definitely better than it is now. It would sometimes have a little trouble starting but the starter button worked and I could usually get it going. It is definitely worse than it was before I did that.

I did not note whether the plugs were wet but I will check that next time I dig into this.

I have not tried a new solenoid. I think testing that and trying a new one may be the next thing to look at when I get a chance.

Thanks for your help!

[thecreature8]

???

You said the fuel lines were gunked but you "cleaned" them? How about replacing them?

That seems like a simple enough task but out of curiosity, if the hoses have been cleaned out well and don't show signs of significant aging or dry rot or anything, is there another reason they might need to be replaced? Would that gunk cause permanent damage that a cleaning won't fix?

[rphillips]

Just from an old country boy, using handles on a pair of plyers, arc across the 2 big wires on the solenoid (don't get excited about the sparks) to see if starter is working right and engine spins over as it should. As long as the batt. is full, this takes solenoid and all other wires, buttons, and connectors out of the question. Be sure bike is in neutral as clutch switch is also bypassed.

[Rob S.]

That seems like a simple enough task but out of curiosity, if the hoses have been cleaned out well and don't show signs of significant aging or dry rot or anything, is there another reason they might need to be replaced? Would that gunk cause permanent damage that a cleaning won't fix?

Not that I know of. I'm just thinking that you can't be 100% sure of what's going on inside a black hose. And they're cheap enough to just replace.

[thecreature8]

Just from an old country boy, using handles on a pair of plyers, arc across the 2 big wires on the solenoid (don't get excited about the sparks) to see if starter is working right and engine spins over as it should. As long as the batt. is full, this takes solenoid and all other wires, buttons, and connectors out of the question. Be sure bike is in neutral as clutch switch is also bypassed.

I was using a screwdriver so maybe that was the problem

That's how I've gotten it to turn over and start up and then immediately die...with that being the case, does that mean the issue (or part of it, anyhow) is after the solenoid?

[thecreature8]

Not that I know of. I'm just thinking that you can't be 100% sure of what's going on inside a black hose. And they're cheap enough to just replace.

Got it. Better to be safe than sorry and easy to do. Thank you!

[Rijko]

I was using a screwdriver so maybe that was the problem

That's how I've gotten it to turn over and start up and them immediately die...with that being the case, does that mean the issue (or part of it, anyhow) is after the solenoid?

no ... because you bypassed the solenoid by shorting the poles

[thecreature8]

no ... because you bypassed the solenoid by shorting the poles

Right, sorry. I was not clear on what I meant. I was only referring to the failure to idle after it starts...the solenoid still needs to be looked at for the issue with the starter button. I think I'm just trying to mentally break things into digestible chunks in my head.

[rphillips]

You're getting there.

[Rob S.]

You're getting there.

But you're losing me. Once it's running, the starter & solenoid are completely out of the picture, out of the loop, correct? And don't try to tell me 'bout 'lectricity, 'cause that's just black magic. "The power of Yoshimura compels you! The power of Yoshimura compels you..."

[Rijko]

Right, sorry. I was not clear on what I meant. I was only referring to the failure to idle after it starts...the solenoid still needs to be looked at for the issue with the starter button. I think I'm just trying to mentally break things into digestible chunks in my head.

that's the way i usually do it, too.

chunk #1, starter works. You proved that by shorting the solenoid terminals and engine cranking.
Next suspect is the solenoid. Like i said, using the green/yellow wire is a nice quick test for that.
If that works, the issue is in the cabling.