Speedo gearbox

[Roostabunny]

I went to search on this and was embarrassed to find my own thread from two years ago. It's been a busy two years, k?

Anyway, I've just now dropped the $2.99 at Harbor Freight for a pair of snapring pliers and got into the thing a bit. For background - my speedo is doesn't work.

I got the snapring, washer, and tabbed ring off. The tabbed ring has one set of tabs - the outer ones. My questions are....

1.) Should there be two sets of tabs - one pointing in to engage the wheel hub and one pointing out to engage the slotted sleeve inside the gearbox? Maybe my inner tabs are kaput?

2.) Can this be disassembled further? I assume so, but I'm hoping for a tip on how to get at the gears themselves.

 

[Steve]

Yes, there should be tabs to engage the inner hub.

Yes, some disassembly is possible, along with cleaning and re-greasing.

You can also unscrew the bushing on the small output hole and remove that part of the mechanism.

.

 

[Dogma]

I don't remember the geometry of that part perfectly, but I do remember that my 850 sheared two wheel-side tabs off flush to the ring. I also remember that I wasn't able to completely disassemble it without destroying the dist seal to investigate further. The grease inside had turned into a gooey almost-dust.

The drive I pulled off the parts bike still worked, so I cleaned and re-greased it. The plastic bushing the output shaft runs in is threaded, so you can back it out to gain access to the gears. I sprayed the inside with whatever solvent I had on hand (maybe brake cleaner), until it was clean. I don't remember what kind of grease I put in it. A light grease like maybe white lithium might be a good idea.

 

[Roostabunny]

Ok, Check - missing one set of tabs. Thanks, fellas!

Steve, you still have any of those parts... two years later?

You guys have any tips for getting that threaded bushing out? My cheapo snapring pliers can engage the thing, but they're too flexible to get that slippery plastic part to turn.

BTW, I was puzzled by a single 3/16 ball bearing I found in there. Oh no! Where are the rest of the bearings? Why is this one loose? Then I had a thought. I pinched it between my thumb and forefinger, and it squished. Turned out to be a "pearl" of dust and grease, packed into a perfect sphere by a million rotations.

 

[Smokinapankake]

On my 84, After pulling the circlip and washer, I just grabbed the center part with a set of channel locks, padded with a rag, and pulled it out past the rubber seal. This allowed me access to the worm gear and allowed me to clean the inside and relube. I used high temp wheel bearing grease, packed in there as much as my fat fingers could get, and reassembled. Some grease spooged out past the seal, telling me that I got it good n wet.
Been working well now for 6 months or so...

 

[Guest]

Try what I found in my thread on the same topic... only stupid me managed to call it the tacho gearbox instead of speedo gearbox...

http://www.thegsresources.com/_forum/showthread.php?t=163684

Correction to the above... try what was pointed out to me in my thread, I just gathered that information in an updated thread...

 

[Roostabunny]

Very nice - thanks, Pete and Smokinapancake!

It was very good to see the pics on that other thread that you found.

Now all I need to do is find a drive plate to replace mine, and there, I'm a little lost. Haven't been able to find it in any fiches, only the whole gearbox. Anyone know a source?