Squashed Speedo Drive. (2011)

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Flo

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Anyone else suffering from the Speedo drive body squashing up, rubbing against the wheel cover & jamming on the wheel spindle?
 
Not trying to be rude, but there are plenty of threads on this issue. Do a search on speedo or speedo gearbox. Usually it's the tophat spacer in the gearbox worn out or the gearbox has been crushed by removing and installing the rear wheel too many times without care. Part number 13270. The gearbox should not touch the rear wheel cover.

Dave
69S
 
Thanks L.A.B., seems the top hat washer is missing. I will order a new gearbox & washer from RGM tomorrow.
I think I know when it went missing.
About 1980, I needed a new one & could only get it with an exchange. So I rode up to L&D motors in Bristol, me & the missus lifted the bike up (no centre stand) & swapped them over. Should imagine the top hat was still in the old one.
 
About 1980, I needed a new one & could only get it with an exchange. So I rode up to L&D motors in Bristol, me & the missus lifted the bike up (no centre stand) & swapped them over. Should imagine the top hat was still in the old one.
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and its run ok for 30 years like that? Just a small point (well quite a big one actually) not all the drives need spacers. I got caught out with similar thread a few years ago and tried to install one and found my drive had a smaller dia hole into which the spacer would not fit. It also has a slightly raised area on inside to do the spacing function. No idea where it came from as it was on the bike when I bought it in '98.
 
Keith1069 said:
and its run ok for 30 years like that? Just a small point (well quite a big one actually) not all the drives need spacers. I got caught out with similar thread a few years ago and tried to install one and found my drive had a smaller dia hole into which the spacer would not fit. It also has a slightly raised area on inside to do the spacing function. No idea where it came from as it was on the bike when I bought it in '98.
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Hmmm...that seems to be what I am experiencing....trying to fit TopHat as per AndoverNorton exploded diagram for '74 850 hub....the TopHat will not fit into the gearbox axle hole from out or inside. If I slip the TH into the hub axle hole, with the flange facing out to the speedo, then the speedo does not seem to mate up properly with the notches in the hub ring. It's the raised ferrule inside the speedo that prevent the TH flange from seating further into speedo housing...gap of speedo casing to hub plate is like 1/8".

So is it true there are speedo's with built it spacers that do not require the TopHat part?
 
Squashed Speedo Drive. (2011)
Squashed Speedo Drive. (2011)
OK, sorted it out. My speedo already had a top hat pressed in for right side...at first glance that appeared to be all one piece of material contiguous to speedo body...but it was just good and squashed together. Used a large socket out side housing to then a ball peen hammer flat space against the inner ferrule, beating down with a rubber mallet got it moving out.
New one pressed in using vise jaws...but managed to bend rim of casing some...should used a block of wood behind to better spread loads.
Gear still turns as good as before...a little catchy, jammy, likely needs replacement ...but speedo now sits further off hub plate than before, which is a good thing....plate is gouged pretty good despite having old spacer in there...maybe just too mashed up?
 
Tornado said:
View attachment 4333 View attachment 4334
New one pressed in using vise jaws...but managed to bend rim of casing some...should used a block of wood behind to better spread loads.
Gear still turns as good as before...a little catchy, jammy, likely needs replacement ...but speedo now sits further off hub plate than before, which is a good thing....plate is gouged pretty good despite having old spacer in there...maybe just too mashed up?
Click to expand...

I found the "catchy, jammy" condition was due to the ring gear being worn to a razer thin edge on the lands, and if the ring land and pinion got just so, the Speedo gear box would jam and rotate. This happened twice, first time I shrugged it off, second time it gouged the hub plate. So beware.

Slick
 
Thx for the advice. My hub plate is already chewed up where the speedo was pressed up against it. Just checked pricing on these things...$90+ CDN from in country suppliers. Are there rebuild procedures/parts?
 
The only viable fix I know of was from Jim (comnoz) who took out the rivets to replace with tiny screws, removed his ring gear, had it hardened (or did it himself ?) and then made a sturdy replacement for the inner "washer" which was held by the rivets. I think that's right.

Beyond my abilities, so I just started scooping up the used units on eBay, tried to pay not more than $30. Some were shot, some were good.
It's really not a nice thing when they fail and gears lock up. If the dogs inside the drive don't snap off, the drive rotates forward, giving the cable a swift yank downward which pulls the inner cable out of the speedometer if you're lucky and see the needle drop to zero while underway. If not lucky you have a cable flopping around near the spokes.

If we cd get Jim to make these improved "washers" and sell them, I'm sure he cd make huge money. Dozens of dollars! :rolleyes:
 
Tornado said:
Thx for the advice. My hub plate is already chewed up where the speedo was pressed up against it. Just checked pricing on these things...$90+ CDN from in country suppliers. Are there rebuild procedures/parts?
Click to expand...
If you mean the thin dish shaped chrome hub cover 06-2082, Walridge in Ontario has them on sale for 22.50 till the 31 of March
 
Northton said:
If you mean the thin dish shaped chrome hub cover 06-2082, Walridge in Ontario has them on sale for 22.50 till the 31 of March
Click to expand...

It's the speedo drive that I was referring to....function before finish is my motto ;-)
 
There are shops in the UK that rebuild the speedo gearboxes.....question is, where do they get the parts? If they use Indian made knockoff parts, the rebuilt speedo drive is no better than a newly made knockoff, which are reported to last only 5K miles, or less.

The Speedo drives are easy to rebuild, if one can get the parts. It seems the only way to get original parts these days is to buy up used units from EBay or from swap meets, and hope to salvage a good ring and pinion from a half dozen or so used units. It is the ring gear that seems to wear most. Comnoz's hardening process of the ring gear might benefit the knockoff ring gears, resulting in a reasonalble life expectancy. Wish Jim would consider providing these.

I hope someone provides us with an option to keep the original type Speedo drives in operation. I would not like to go digital out of desparation..... I feel the "soul" of the Brit bike resides in the original clocks.

Slick
 
From Slick: "I would not like to go digital out of desparation..... I feel the "soul" of the Brit bike resides in the original clocks."

What? I thought the Soul resided in the points ignition and those using EI were demon-spawn?

Being as new/NOS Smiths drives are around $90 CDN, makes it tough to throw money at rebuild services...going to be close to same cost and likely same reliability. Ideally, failed components could be mass produced and sold significantly cheaply, then we'd all be happy throwing in new gears every few seasons as prevetative.
Don't think that is likely to happen. Market likely too small vs tooling/startup costs etc. Unless we can find a manufacturer in a cheap labour country to make batches for low prices....and have decent quality.
 
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