starter motor problem

Anything to do with motorcyles
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stuartgurney
Posts: 16
Joined: 06 Nov 2020 14:41
Location: lyme regis

starter motor problem

Post by stuartgurney »

I put my issues on the bikes for sale page in error before -
Now I need you collective wisdom.

To recap the starter on my strada is great when the bike is cold, but a problem when its hot.
Cleaned the "sprags" etc and for a day or two its was fine. But no longer.

I know that the "sprags" are gripping OK as if I try with the bike in gear it shoots forward.

There is very little compression when cold - I can turn the clutch drum by hand. But the bike runs really well and lots of power.

I can kick start when hot and starts fine.

The only thing that I can think is that when the bike is hot there is more compression, hence more load on the starter motor, which then reduces the amount of juice for the ignition sytem? Is this possible and what to I do?

Stuart
3potjohn
Posts: 1243
Joined: 02 Jun 2007 13:58
Location: Devon

Re: starter motor problem

Post by 3potjohn »

To get the best out of the starter I have found it necessary to have a decent battery. I did have a PC680 on my Sport but replaced it as it was at least 12 years old. This made a lot of difference. I also have stripped ,cleaned, reassembled the starter motor and it’s gearbox and replaced the seals and bronze gear.I had the separate little oil seal type, rather than the seal in the needle bearing design.Replacing this seal has stopped it dribbling oil . I was fortunate to obtain a new brush holder and brushes.The old one looked like it had been pulled from Jacque Cousteau’s dustbin.
I have fitted the later type starter shoes and another but secondhand relay as the original had a habit of welding it’s contacts on occasion , resolved by a boot!
After all of this mine starts OK except on a very hot day in August after a 30 mile run when it was sluggish.I cannot figure that one.
The rebuild videos Paul Compton did were very useful.
Maybe not much help...
John
stuartgurney
Posts: 16
Joined: 06 Nov 2020 14:41
Location: lyme regis

Re: starter motor problem

Post by stuartgurney »

Hi John

its really strange - perfect when cold but nothing when hot. There is the same voltage drop at the battery hot or cold. Motor spins perhaps a bit more slowly

It may be that a coil, or other compenant fails when hot.

I will try and change components one at a time.

Stuart
stuartgurney
Posts: 16
Joined: 06 Nov 2020 14:41
Location: lyme regis

Re: starter motor problem

Post by stuartgurney »

I took off the motor. About 1cm thick grease/copper/crud around the brush plate. Thorough clean, skim 2 thou off armature- now starts every time

Spot on
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