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Starter Motor Refurb

By Liam Moran

During the rebuild of the GL1200 Standard, one of the tasks I had to tackle was the refurbishment of the starter motor. There are two different types of starter motors fitted to GL1200s. The 1984 model was different to those of subsequent years. This is my 1984 starter motor just after removal from the engine. You can clearly see the broken gasket.

Another few views of the motor in the following three pictures.

The first step in dismantling the unit was removal of these two screws.

The innards of the epicyclic reduction gearbox are here.

This is the motor end. The dangly gasket is clear to see.

This is what the commutator and brushgear looked like.

Removal of the screw allowed the entire brushgear assembly to be removed in one piece.

We are then left with the exposed commutator. The bearing at this end feels very rough.

The stator can then be just lifted off the drive end cover.

This is the stator after removal.

This is the rotor with the drive end cover. Note that the bearing is a plain brass bush.

In the previous picture you can see these shims fitted on the rotor shaft at the drive end.

Here is a typical rebuild kit for the starter motor. Included are:

  • Non drive end motor bearing

  • Drive end motor brass bush

  • Reduction gear final drive bearings

  • Brush Carrier and brushes

  • O rings and seals

  • Main terminal connection fittings

A kit like this costs about $25.00 from many suppliers in USA.

After a bit of cleaning up, this is the rotor with the old bearing removed.

And here is the stator after a good compressed air jet cleaning.

I used a little container of engine cleaner to clean all the old grease off the gearbox innards.

The final drive element just taps out of the housing after the retaining circlip was removed.

Here is the output shaft and final gear stage. One bearing and the seal stays in the housing the second bearing stays on the shaft as shown.

This is the housing after removal of the gear.

The housing with the bearing and seal removed.

This is the method I used to remove the bearing from the shaft.

This is the bearing almost off.

The old bearings and seal.

This is how I pressed the new bearing on to the shaft.

New bearing and seal installed in the housing.

The reassembled output stage.

This is the old brass bush after removal from the motor drive end housing.

And the new bush on the way back in.

Keep an eye on the outer Annular gear as this is only held in place in sandwich fashion by the housings. Watch for the locking pin, this prevents the Annular gear from rotating.

This is the annular gear fitted loosely to the output stage.

A dollop of grease to keep everything lubricated.

This is the new square section O ring seal. Also clearly visible is the Annular ring anti rotation pin as mentioned earlier. It had become dislodged during a trial assembly/dissassembly earlier.

The reduction gear unit after reassembly.

Watch carefully for these thrust washers as you reassemble the rotor into the reduction unit.

The rotor just pushes into the reduction unit. If it does not insert cleanly, do not force it but retract it and rotate the gear reducer output shaft very slightly and attempt reassembly. Everything should just slide together.

The stator can then be fitted. A new O ring seal fits onto the stater to seal the joint.

When assembling the motor, be careful to align the marks shown.

The new bearing was fitted and the new brushgear holder.

Be careful when fitting the brushes. One brush has an insulated connection cable this must be fitted in this brush holder.

The non drive end cap can be fitted to the motor after fitting an O ring seal.

Again, watch these alignment marks.

Refit the motor tie rods.

The kit also included these new insulators and nuts.

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Denis Dwyer
Denis Dwyer

Excellent article, very informative. Thanks Liam.

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