Friday, June 8, 2012

And now, for something completely different

This is a little outside the ballywick of this blog but it may be relevant for someone, and electrons were involved.  I have a 1976 Kawasaki KZ750B1 vertical twin which followed me home one winter day back in 2010.

I didn't work on it at all in 2011 but this year I decided I was going to get it up and running and evaluate its mechanical condition prior to deciding on a modification plan. The battery was completely defunct so I obtained another and found that the starter was very weak.
I got a set of starter brushes and earlier in the week I decided to tackle an overhaul.

To remove the starter one has to remove the alternator cover to access the starter sprocket, remove the two mounting bolts and the battery lead, and slide it out to the right with a little help from a mallet and a soft drift.

But wait! If that's what you do, you'll never unscrew the two long screws that hold the starter together. All you'll do is strip the screw heads. So do this before you unbolt and remove the starter like you should have done in the first place.

So get yourself a proper sized phillips head bit and a socket to hold it, a couple adapters and a half inch breaker bar or a good healthy speed handle. Dab some coarse valve grinding compound on the bit, seat it properly in the screw head so it doesn't slip, lean into it and tighten it a little-that's right, tighten it. It'll break the hold of corrosion and then it can be easily unscrewed.

While you were reading this it should have occurred to you to use this old aircraft mechanic's trick on all the alternator cover screws. Otherwise you'll just wreck the screw heads with that idiotic impact driver you bought. If you've ever had to pull the wing planks on a Falcon 20 you'll never forget this trick, and you'll be glad someone taught it to you.

When disassembling the starter pay particular attention to the illustrated blowup from the Kawasaki manual and where your shims are located and take pictures if necessary. When that little item marked 22 in the picture falls out


Clean the parts with white gas a/k/a Coleman fuel and blow them dry. Then you can test the armature.  Once you've tested and cleaned it with emery cloth and cleaned out the schmutz from the commutator grooves you can put new brushes in and assemble that end of the starter.

Putting the drive end together is a little dodgy. It only goes together one way, the body and housings are marked with index lines, and number 22 gets inserted in the appropriate place in the proper direction. Make sure and grease the planetary gears and sun gear.

Now, you can reef those screws down because without adequate torque on them the sun gear will slip and spin around. Put a screwdriver through one of the mounting holes on the commutator end housing and position it against something solid like the floor. Then use your disassembly rig to tighten the screws up.

Lastly, test it on a battery, and if it runs install it and be happy. You'll probably find that the starter clutch is shot, too, about which we shall speak more anon.

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