CB750F2 starter motor

[miclyn]

I am having problems starting the bike. New battery fully charged but when trying to start the battery drains quickly and the starter motor is labouring. Looks like the starter is faulty. Does anyone know where i can get it reconditioned fairly locally to Upminster, Essex

[Tomb]

Have you tried stripping to grease the planetary gears, sorry I don't know the CB750's but all the starter motors I've worked on get dry and then slow, next is replacement brushes.

Just a thought

[miclyn]

Not tried anything yet as i thought i would just post to get some ideas.

[mick]

Hi Mike your probably better off taking it apart and cleaning it etc yourself  , theres plenty of help on here if you get stuck, cheers Mick.

[miclyn]

Stripped down starter cleaned out carbon dust. Brushes and commutator all ok. Reassembled put it back on bike and it's still the same. On the button it turns over ok for about 5secs then slowly dies by which time the battery is drained. even with 2 batteries connected fully charged it's not much better. Any ideas. I am at least able to kick start it even though it's running rough at the moment. Going to balance the carbs tomorrow.

[mick]

Hi Mike, only thing i can suggest is makes sure all your earths are good and all your connections aswell, others may chime in with better ideas?, cheers Mick.

[Tomb]

next is replacement brushes.

 

[Waggles]

Must admit I would replace brushes anyway if you had it apart and clean commutator. If thats all OK and the bearings are OK (not dry or worn allowing the motor to go out of line) then I would check the relay next

[K2-K6]

Are either the earth lead or positive lead getting hot during the turn-over? if so they are not passing sufficient current.

Try connecting the extra battery to where the earth meets the engine and positive staright to the starter post (may need two people) to see if it's any better. If it is, then you could have a fault on the wiring or an inconsistent earth.

[miclyn]

I have tried all of the suggestions except new brushes. The only thing that gets warm is the starter motor. The brushes were within the tolerence in the manual, there was no burning on the commutator and it did not need under cutting. The only other thing i suppose is the windings in the motor. Just wish i had a spare starter to try before taking the plunge and buying one.