Starter problems 3.5 Strada 1978

[hotfoothowell]

My self-starter suddenly refused to function, just giving a click in the starter relay. Checked all the leads for tightness, and battery condition, then pulled the starter motor off, wouldn't turn over on a slave battery. The gearbox sprocket could only be turned with a wrench, so off it went to a starter motor specialist, who pronounced nothing wrong with it, and thought it might be the relay. I had already tried shorting the two main terminals of the relay, no result, so I changed the relay for an identical one, a new Durite 07 27 10 model, 12volt 100amp., exactly the same result, merely a clicking in the relay. Help! Can't think of anything else, though I still think the gearbox should not have been so stiff. I did notice that there was no oil filler as per the handbook, and one threaded 4mm hole where the filler should have been, minus any filler plug.
Patrick

[Ralph]

My self-starter suddenly refused to function, just giving a click in the starter relay. Checked all the leads for tightness, and battery condition, then pulled the starter motor off, wouldn't turn over on a slave battery. The gearbox sprocket could only be turned with a wrench, so off it went to a starter motor specialist, who pronounced nothing wrong with it, and thought it might be the relay. I had already tried shorting the two main terminals of the relay, no result, so I changed the relay for an identical one, a new Durite 07 27 10 model, 12volt 100amp., exactly the same result, merely a clicking in the relay. Help! Can't think of anything else, though I still think the gearbox should not have been so stiff. I did notice that there was no oil filler as per the handbook, and one threaded 4mm hole where the filler should have been, minus any filler plug.
Patrick

Do you mean filler or filter? I would check the oil level, if you mean one of the filter bolts is missing it could have lost its oil and seized.

[3potjohn]

The starter system is in my view primitive( not always a bad thing though) but can work.Assuming the relay is Ok as you say and the contacts on the battery and motor body are sound, then it surely can only be a battery/motor issue. I think as far as I recall that the starter gear is quite hard to turn by hand. You can dismantle the motor. I fitted a new oil seal and got a new rubber filler bung but this didn't seem to fit very well. What is the battery output like? A clicking solenoid is usually due to insufficient current/high resistance e.g.due to poor connection

[EVguru]

The gearbox is a worm drive (five start worm as I recall), so backfeeding it is going to be pretty hard.

The relay does of course click as it pulls in normally, it's only if the relay buzzes or chatters that you would suspect the battery or a poor connection.

I'd suspect stuck brushes. The motor relies on a sealed bearing in the gearox to keep oil out and they often don't leading to a sticky black mess. I have a couple of motors to look at, but haven't looked into the correct way to take the brush housing off yet.

[HoveActually]

Here are photos of my starter motor dismantled, but after cleaning! It was really a mess because of oil leaks. The brushes must be in good condition (renewed if need be) and the commutator really clean, especially the slots between the copper lands.

With a 14Ah battery (pinched from a BMW K1300S - yes it does fit) the starter spins the motor easily; starting is immediate - pity it doesn't run thereafter as it should but that's the subject of another post.

MoriniStarterMotorDismantled2.JPG (217.59 KiB) Viewed 6324 times

StarterClutchMechanism2.JPG (225.85 KiB) Viewed 6324 times

[hotfoothowell]

Your suggestion seems to make sense, Paul. I guess the brushes could be worn/ stuck/dirty, so that when bench tested, the motor appears to be functioning, but when under load on the bike, they are not up to the job.
As for the gearbox, what I took to be a filler (not filter) hole - albeit somewhat small at 4mm -had nothing in its thread, and no oil emerging. According to NLM's book, it should have a filler and an oil level hole, so I am wondering whether modifications were made to let it run on grease. I haven't had the motor apart yet. Thanks for your contributions, Patrick