Bike sometimes won't start...

[Pete]

Sometimes when I go to start my bike it won't! All I get is the 'drilling' noise from the starter motor, but the engine won't turn over. I know it's not the battery because when I check it with a multimeter it reads 12.8V which is spot on. I went for a ride today and when I got on initially it fired up straight away. Then when I got back someone had parked a car in the way so I had to go into the house and move it...went back to my bike and got the same old drilling no starting problem...so I rolled it into the garage, checked the battery, all was fine and then it started up!

My guess is a loose connection somewhere but I'm bugge*ed if I know which one! Any help greatly appreciated, of course.

Oh and a bit more information just incase:

- Sparks have recently been regapped and cleaned with brass wire brush (last week)

- Petcock was working fine on last check (last week)

- Yes there's fuel in the tank!

- Both battery terminal wires were taken off and given a good scrub, as was the earthing connection (last week)

- Lead going to starter motor was given a good push just to make sure (again last week)

- New air filter fitted (last week)

- I've never used a pressure washer on any part of the bike (except the fairings when they've been taken off and away from the bike)

[cruz]

Sounds like the starter is/could be on it's way out.

Will it bump on the occasions it doesn't fire up on the button ?

[Pete]

Hi cruz! I was beginning to think no one was going to reply!

Yeah it bumps perfectly everytime I try and bump it and runs great. I'm going to have a closer look at the starter today and the starter relay and give all the connections a good scrub down. I should really check the brushes inside the motor but to do that I've got to take out the fuel tank, the air box, the throttle and clutch cables, the carbs, the alternator, THEN the starter motor! I'll probably do that anyway because it's such a lovely day for working in the sunshine with the radio on!

[rosszx9r]

Hi cruz! I was beginning to think no one was going to reply!

Yeah it bumps perfectly everytime I try and bump it and runs great. I'm going to have a closer look at the starter today and the starter relay and give all the connections a good scrub down. I should really check the brushes inside the motor but to do that I've got to take out the fuel tank, the air box, the throttle and clutch cables, the carbs, the alternator, THEN the starter motor! I'll probably do that anyway because it's such a lovely day for working in the sunshine with the radio on!

 

i think you'll have to bite the bullet and strip the starter motor down!

the power to the motor goes via a pretty meaty contact that gets made by the solanoid pulling the motor into it's drive position. the solanoid is easy enough to check as you'll hear it click when you tried to start the machine, the main power contact is the main suspect followed as you guessed by the motor brushes.

have you checked/ cleaned the earth connection for the starter and battery?

[Pete]

I thought as much about stripping the motor ! Oh well it's all experience, and at least this time I'm dragging my feet on it because I know what's involved rather than worrying about breaking something!

I've had a look at the starter relay and it looks OK but I've not taken the connectors off. Been a bit of a busy day today so haven't had chance but it's on the list for tomorrow. I think I'm going to undo any wires I can get at and give them a good clean and see if that affects starting. If it seems the same I'll probably bite the bullet like you say and have a peak inside the motor...I'll probably do that anyway knowing me - once I get the fairings off (that all important first step into commiting one's self to a job!) I tend to just carry on dismantling stuff at leisure!

Thanks for the ideas guys, I'll let you know how it pans out tomorrow.