Starter Motor question……

[Fellhopper]

I have a problem with the starter motor on my 2003 1150GS. The problem began with the starter seemingly failing to engage and turn the engine over. It would still make the fast higher pitched sound which I think is the motor itself running but I am thinking that the gear isn’t being thrown forward by the solenoid? It would do this perhaps once every 10 goes then this increased to nearly every time the starter button was pressed.
I have stripped and rebuilt the starter motor ( see photo - there is some arcing on the plate but all OK ). All magnets present and correct, all lubed and moving freely but the problem persists.
Before I order a new starter motor does anyone have any thoughts? If it is the solenoid switch, presumably this can be bought separately.

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[Ian J Hartley]

Your photo shows that at some stage in the life of the starter motor, the grease plate cover for the planetary gearing has come adrift shorting out the windings on the stater motor. This is not good and the high current that has caused the welding spots is also not good for the windings. Usually you can get away with refitting the grease plate or better still binning it all together to prevent a future occurrence.

I machined a replacement for mine out of plastic.

It could well be that one or more of your windings are damaged, and could be the cause of your symptoms. When you rebuilt the starter motor, did you check the windings for continuity?

Also, the black plastic housing for the brushes can become brittle with age and crack or break.

 

[Stanley Knife]

Similar thing happened to mine about 12 years ago,I removed the plate and it has been fine ever since,I stripped it this winter just to check and all was well.