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Tachometer Gearbox Issues

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I ran into an issue with the tachometer gearbox that is worth sharing.  There is a zerk fitting on the edge of the gearbox and the WSM talks about it in the Lubrication Section P.4, Item #5, "Revolution counter drive gearbox (one nipple) every 6,000 miles (10000 km.) two strokes.  Sounds innocent enough, but there's such a thing as a limit.

 I had been sensing a reduction in the output of my generator for some time now and decided that it was probably time to refresh the brushes. They haven't been touched since I installed the new armature about 14 years ago. When driving in parades I tend to roll along a walking pace by running at idle speed in 1st gear with my foot on the brake pedal.  A problem has been in viewing the drain that shows on my ammeter due to the stop light bulbs.  A Christmas present for Lazarus was a set of tail light LEDS from Abingdon Spares to cut the current way down.  Along with the order for the LEDs I ordered a set of bushes.

Two weeks ago I had to attack the brushes issue when the Ignition Light would not go out when I fired Lazarus up to take him for his January ride.  One of the first steps was to uncouple the tach gearbox from the back of the generator.  When I pulled it off I was met with an ugly sight of a strange mess of grease, with brass shavings in it, on the output end of the generator shaft:Generator Grease



Yecch, a mess.  I'll have to clean that up.  Next step was to remove the generator and move it to the bench to do the brush replacement.  One of the first things that I've been meaning to mention is my technique for holding the generator pulley while I loosen, or tighten the locknut.  A tool that I've found handy for that is a vice-grip chain wrench. It wraps very nicely around the pulley and allows a socket to loosen the pulley lock nut:Chain Wrench

When I got the armature out and looked at the commutator I couldn't believe my eyes. It was covered in a film of grease.  No wonder there wasn't much current.  The brushes were barely in contact with the segments.Greasy Gen

Looking at the end housing of the generator showed it to be home to a film of grease:Housing Grease

A bunch of spraying with cleaner and a judicious application of fine sandpaper on the commutator cleaned things up quite well:Cleaned commutator

As they say, reassembly is just the reversal of disassembly.  The generator is back in place while I contemplate the degreasing of the tachometer gearbox.

More later when I figure out how to handle the greasing of the tachometer gearbox.

1/29/19 -- Update.  Notice the formerly greasy commutator that was cleaned up and sanded.  The brushes were barely making electrical contact with the segments.  Yesterday, 1/28/19, I was finally able get Lazarus out for his January run.  I was flabbergasted by what I saw on the ammeter -- above 2000 rpm the ammeter was showing just about 30 amps of +current!! I'd had a 2amp float charger hooked up for a few days.  I'd never seen that high a charging current before.  I turned around and drove back home.  I could see the current dropping off as I got to the garage.  Weather permitting, I'll put an external ammeter on the generator output lead and prove the current while I monitor the battery voltage.  Stay tuned.


(508) 317-9412 (cell phone/text okay)
January 22, 2019, edited 1/29/19