Starter button only works 30% of the time. Where do I start?

[spenczar]

Preface: I've been working on my 81 GS650G for a few months now. With cleaned out carbs and adjusted valves and a petcock that doesn't leak, it's riding like an absolute DREAM compared to how I got it. Wouldn't have been possible without the guidance from GSR so thanks for everything, everyone.

Now that it runs really well, I'm starting to work on the weirder glitches. Here's one: my starter button works only about one in three times I press it. This is when the bike is cold. I'll put in the keys, pull out the choke, squeeze the clutch, switch it to "on" and then push in the starter button. Usually, literally nothing at all happens. No sound, no engine trying and failing to turn over, just nothing. I'll flip the engine cutoff switch off then back on, then press the starter again. Usually nothing again. After a few tries, though, it'll actually work, and it'll start right up, no problem.

Where do I start looking to fix this? I'm thinking a loose connection in the starter button or something maybe, but is there anywhere else I should be checking?

[JEEPRUSTY]

my money is on a marginal starter interlock switch.
Try wiggling the clutch lever up and down while you have it pulled in.

My lever has a bit of free play that requires me to pull back and slightly upwards to make contact.

[Agemax]

strip out and check all the contacts are clean and secure in the starter button and kill switch to start with, then the clutch safety switch,and make sure it is operating correctly

[GSScoobie]

Start by deleting the clutch safety switch by connecting the two wires that go to the switch in the headlight bucket.
Then spray some penetrating oil into the start switch and see how well it works then.

[JEEPRUSTY]

If and when opening up the switch be careful of any springs and other bits that might pop out when pressure is released.

Sproing! is a terror inspiring sound.

I would isolate the clutch starter intelock switch first just because its so darned easy to do.

[Biggie]

i had the same problem too, and i found a corroded ground cable, right under the starter relay that was the problem. Take off the starter relay and unscrew the black wire, clean the connector and put everything back together.

[blowerbike]

i am with rusty jeep on this one.
damn clutch interlocks are crap ans cause cranking problems.

[Redman]

When it doesnt go try wiggling the starter button for a while to see if that is your problem. If so then take control apart so can cleanup the button contacts.
When it doesnt go, try wigling around the clutch lever to see if thsat is tyhe problem. If so, loosen the screws that hold the switch mechanism and see if can move around to where it does work better. If that doesnt help, can take apart the switch and clean up.

Would be better to troublshoot this with a volt meter. But try wiggling the button while holding it, and try wiggling the clutch lever while it is pulled in.

.

[Steve]

Guess all you want, what you need to do is follow Nessism's advice in his signature: "To measure is to know".

OK how do you "measure" electricity? In this case, you only need to verify its existence. Fasten a test light to the small wire (yellow/green) on the starter solenoid. Go through all your motions, including pushing the button. Does the test light come on? If not, move upstream. Fasten your test light to the wire that comes off the "dead" side of the engine stop switch ("kill" switch). Does it light up when you turn on the key?

It's really a rather simple process if you follow a logical path. It might be easier to start at the fuse, to make sure it's working OK, then follow the wire through all of its connections and switches until you find where the connection is broken.

.

[Remington44-77]

Electrical contact cleaner. Available in a spray bomb from any electronic supply house or Radio shack. Give the switch a shot and work it to loosen up the crud.
Good stuff.

[Steve]

Electrical contact cleaner. Available in a spray bomb from any electronic supply house or Radio shack. Give the switch a shot and work it to loosen up the crud.
Good stuff.

You are assuming there is crud in the switch.

May be that there is no power getting to the switch?

Use a test light, see if there is power or not.

.

[Remington44-77]

The crud I'm referring to is corrosion. And yes do all the other electrical checking necessary. I'm just saying that sometimes a shot of contact cleaner clears up the problem. Some times not. It doesn't hurt.

[spenczar]

Using Steve's excellent advice about how to think about testing electrical problems, I figured out that it was a busted starter relay. The internal wire (the one that connects to the starter button) was frayed, which might have been causing a short a bunch of the time. I replaced the relay with a new one, and it's been working well now. Thanks everyone!