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Post by zilch56 on Mar 16, 2012 9:33:53 GMT -4
This specific document applys to triumph motorcar speedometers but the concepts and construction of the mechanical speedometer systems are similar. home.comcast.net/~rhodes/speedo.pdf |
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Post by zilch56 on Mar 19, 2012 10:49:54 GMT -4
members.shaw.ca/randell/Smith/Speedo.htmlThis is more info on speedometer repair. I am delving into my speedometer and going to clean and lube the parts as they recommend in the airticle above. it sat dorment for 8 years and is bouncing all over and sticking. The bouncing is most likely a cable issue but the sticking is gummy internal works. I post here how it goes with pics and such if anyone is interested in the future.
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Post by hogsausage on Mar 19, 2012 12:20:00 GMT -4
I have those same problems with all my smiths. Repair of them is really low on my list at the moment as I've been driving without speedo and tach for years, plus I have other pressing issues. It would be nice to have them working properly though!
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Post by zilch56 on May 2, 2012 9:34:16 GMT -4
I am going in on my speedo this week. I opened it and confirmed the magnet is contacting the spring loaded aluminum pick up disk for the needle. I am going to diassemble it and try to repair the bushing on the input drive. We will see how it goes.
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550fi
Junior rider
75 CB 550 F1,79 CM 400 A,72 CT 70 K1,Unknown ct 70 clone 05 GY6 scooter ,70 CT 70
Posts: 624
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Post by 550fi on May 2, 2012 11:42:03 GMT -4
That will be interesting.Ive read posts where they used a fork to get the needle off,good luck.
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Post by zilch56 on May 2, 2012 21:27:08 GMT -4
I did not want to fork the needle up so I worked it up with my fingers.  . It came loose pretty easy, Then I removed the two plastic face plate rivets. I found there are four small rivets: two hold the trip counter retaining bar and two holding the input drive/magnet. One of the rivets holding the drive magnet mechanism down had worked loose allowing the drive magnet to rub the aluminum needle disk. It worked loose due to vibration witnessed by the gray dust under one rivet. I've seen the same effect on aircraft rivets. The rotating magnet and the aluminum disk need to be very close but not touch according to the repair documents. I am going to clean and lube it, reassemble it with new fastners and adjust it. I think that will do it. |
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550fi
Junior rider
75 CB 550 F1,79 CM 400 A,72 CT 70 K1,Unknown ct 70 clone 05 GY6 scooter ,70 CT 70
Posts: 624
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Post by 550fi on May 2, 2012 23:14:50 GMT -4
You must have some good eyes and steady hands.
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Post by zilch56 on May 3, 2012 8:46:14 GMT -4
Sorry, I was making a bad play on words. My eyes are ok for a geezer. When I first pulled the needle of I grasped the center of it between my thumb and index finger and rocked it off carefully. But the second time I used the fork and it is a much better way to pull it off. Thanks for that tip.
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. It came loose pretty easy, Then I removed the two plastic face plate rivets. I found there are four small rivets: two hold the trip counter retaining bar and two holding the input drive/magnet. One of the rivets holding the drive magnet mechanism down had worked loose allowing the drive magnet to rub the aluminum needle disk. It worked loose due to vibration witnessed by the gray dust under one rivet. I've seen the same effect on aircraft rivets. The rotating magnet and the aluminum disk need to be very close but not touch according to the repair documents. I am going to clean and lube it, reassemble it with new fastners and adjust it. I think that will do it.