Join Date: May 2007
Location: Perth, Australia
So update on this thread - yes, I let the bike sit for months and did nothing.........So the short story is that it is the starter motor and now I need to find somewhere to buy a new one or a reconditioned second hand one, but in the meantime I wanted to share my experience to help others:
First of all I tested the solenoid as suggested. It is really easy to test, although having the service manual is helpful to work out the connections. You need to remove the entire battery/relay box, but other than that it's easy. It is SUPER HELPFUL if you have some electrical test-leads with spring/croc clips on them. COnnect it all up and you will hear a loud and positive click as the relay turns on and the multimeter will show short circuit to show that the relay is working find.
So next step was the starter motor. I wouldn't say it's easy to remove, but it's not difficult either. Again, service manual is helpful. It's really only one cable that needs disconnected and two bolts and the thing can come out, but it does need a bit of wrestling to get it out past all the cooling pipes.
Once the starter motor is out I tested it by using the same battery/solenoid setup that I had used to test the solenoid, except this time you are putting the starter motor in series with the high voltage output from the starter solenoid. You can use car jump leads for this to help, they are perfect and the legnth allows you to put the starter motor on the floor and put your foot on it (remember that if it works the starter motor is going to violently try to move). When I tested the motor didn't turn at all so I knew this is where the problem lay.
While I was testing it and getting nothing from the starter, I tried twisting the output shaft and low and behold it starter turning - bingo, so probably the brushes right?
Next step - pull the motor apart. Now this bit is super easy. Just a couple of bolts and it almost falls apart. Interesting enough, I got traces of smoke coming out as I opened up. My guess - excess carbon from the brushes burning. As I opened it up I was presented with a chamber that was full of carbon powder - 19 years work of brush degredation. There was still some of both brushes remaining but not much (maybe 2mm ish max). I cleaned the whole thing up and reassembled then re-tested and it worked perfectly. Span up on every test. But I was surprised it wasn't particularly violent/strong when it started up (this was a clue I think).
Anyway, I reassembed the starter motor into the bike. Getting the starter motor to slot back into the engine is a little tricky, I guess because the teeth on the shaft have to match the position of the cog in the engine or it wont go in. Took me about 2 or 3 attempts of adjusting shaft position on the motor then re-offering it up to the engine before it slotted in, plus it needed a rubber mallet to push it in with a little tap rather than the strength of my hand alone.
Sadly when I tried to start the bike nothing had changed - it still wouldn't start. I could hear the starter solenoid switching, but nothing from the starter motor. My guess - either the brushes or the armature are so toasted that there is no cranking strength in them so it is trying to turn but getting nowhere. Although, I'm surprised I couldn't at least hear/feel something from it, but there was nothing at all.
In summary, 90% sure the starter motor is screwed and now looking to source a replacement. If anyone has any suggestions then I'm all ears!
2001 Red ZX12R, 45000kms, PCIII USB, Remus Titanium Exhaust, Pilot Jet Mod, Various CF Parts, Bridgestone 020s