GPZ500s being a bitch about starting...

[Bomberman]

Hi all,

So... I may have posted this before, but BCF's search function appears to have pretty much become google search?

Anyway, a while back my bike would sometimes click from the solenoid but do nothing else on pressing the starter. After a few presses it would fire and be fine though. It got worse so I ordered a replacement solenoid from a breakers, and optimated my battery (it was fine). While I was waiting for it I did some reading around and giving the solenoid a sharp tap with something heavy could fix it. No idea why this is but I tried it and (could have been coincidence) the bike has been flawlessly starting for a couple of months.
Until yesterday. Going to set off, click, click, click. Bugger. After an age, I discovered if I put it in gear and push forward and hit the starter it fires fine. I know that sounds like a bump start, but I was sat on the bike and moved it maybe a couple of inches very slowly. Drove where I needed, left it acouple of hours and it was fine when I came back to it. Fired first time.
Got home, decided to swap out the solenoid. It hasn't fixed the problem I got it going this morning with the mini bump trick fine though. In all other respects it's running really well.

Any thoughts? Starter sticking/failing?

Cheers
____________________
'Allo! My name is Inigo Montoya, you killed my father, prepare to die!
'89 TZR 125 - '94 GPZ500s - ZK3 GSXR600 Alstare

[stinkwheel]

That sounds very like it's the starter motor itself.

Don't know how familiar you are with an electric motor but there's almost certainly a problem with the commutator.

If the motor stops on a "bad sector" it can't turn. Your wee bump forwards will rotate the starter motor slightly so the brushes are on a good sector and it'll then work.

We had to do this for a week or so with my Dads toyota hilux one time until we had time to change out the motor.

To test this, try shorting across the two terminals on the solenoid with a coin/screwdriver next time it happens. The starter motor should turn regardless of any other factors because that effectively connects it directly to the battery. If it doesn't turn and the battery is good, the problem is the motor

If the starter motor is strippable, it might just be a build-up of carbon between the commutator segments, taking it apart, scraping the carbon out with a fine screwdriver and cleaning up the surface with some fine wet and dry paper can do the trick. Inspect the brushes while you're there. COuld also be a broken wire going to the commutator.

It may also be the case that it's a sealed unit and just needs replacing.

The commutator is the copper bit on the attached image (which is a generic starter motor picture). The grooves between the segments should be free from carbon and the surface should be clean copper.
https://www.peachparts.com/shopforum/attachments/diesel-discussion/89498d1297330792-om617-starter-motor-life-not-just-christmas-starter-motor-cleaning-commutator.jpg
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Bomberman]

Thanks for that Stink, what you say certainly chimes with the way it seems to feel. I'll give the coin trick a try on my way back.
Cheers

edit; Actually, one thing - how come it went away for ages? Could there be something loose in there?
____________________
'Allo! My name is Inigo Montoya, you killed my father, prepare to die!
'89 TZR 125 - '94 GPZ500s - ZK3 GSXR600 Alstare

[Mikey3]

If its not the communicator I had a similar problem on my CG125 some years ago.
My problem was that the small brushes which rotate the communicator were too worn out they could no longer reach it so I had to order new ones.
The intermittency of it does swing towards Stink's theory, but here's just another one incase that's not it .

HTH,

Mike
____________________
'04 Yamaha WR450F
'99 SV650 Streetfighter Project - mid build
'Motorcycling is about what you do; not about what you own, or how much you spend on it'

[Bomberman]

Cheers Mike, something else to look at
____________________
'Allo! My name is Inigo Montoya, you killed my father, prepare to die!
'89 TZR 125 - '94 GPZ500s - ZK3 GSXR600 Alstare

[Bomberman]

Hm, OK additional...

Bike carried on doing the same today. Got home parked up. Tested it while parked, click click click. Cool thinks I, I'll get changed and do the test as per stinky's suggestion. Back to the bike, decided to give it a go and it fired up straight off

So fired it up four or five times till I got it to fail. Click, click, click. Then I hit it with a hammer. Brum!

Thoughts?
____________________
'Allo! My name is Inigo Montoya, you killed my father, prepare to die!
'89 TZR 125 - '94 GPZ500s - ZK3 GSXR600 Alstare

[jimspeed]

could be worn out brushes or the brushes sticking in the holder, the tap with hammer is shaking them about and maybe helping them contact the comm? either way sounds like its time for a new starter motor unless you can get service parts for it?
____________________
Hyosung cruise 125(passed test on, sold) Kawasaki el 252 (better than expected but sold on) Kawasaki GPZ500S first "big"bike.(sold) ZZR600 E5..Z750 2007,ER5, currently on a 2008 Enfield bullet electra x and loving it..
,"Alpha-9: Is there any correlation between dyno rod and dyno kits?"

[stinkwheel]

If you can get in there, you can even make your own brushes by filing down ones designed for use in a washing machine motor (which are big and cheap).
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Ariel Badger]

[Bomberman]

Cheers lads, bit more to think about there (especially from you Ariel ).
Think I'll trawl ebay for a replacement as it doesn't look too bad a job to swap out. In the meantime I'l keep hitting it with a hammer
____________________
'Allo! My name is Inigo Montoya, you killed my father, prepare to die!
'89 TZR 125 - '94 GPZ500s - ZK3 GSXR600 Alstare