It's probably stripped the driven gear inside it. Disconnect at the wheel end and spin the wheel to see if the gear turns. Sometimes you have to load up the gear to see if it slips.Stick something into the square hole to load it when spinning.Otherwise the inner cable is either not quite long enough or its in the outer the wrong way.

 

The gearbox can fail if somebody lets the cable get rusty or siezed. The drive gear simply chews thru the stationary driven gear and it's finished.

Put your bike on the center stand and turn the rear wheel. If the cable does not move, then the gearbox is probably shot. Yo have to pull the rear wheel to replace it. Smiths are only available used or if you get lucky as NOS. But they make repros in Asia that work fine. I have one on my bike. The PO let the cable seize and killed the original Smiths box. Repros are not cheap. About $70 if I remember right.

Clean out your cable sheath and the drive cable with min spirits. Then lightly grease all but the last 6 or so inches of the drive cable and put it back in the clean sheath/housing. You leave the last 6 inches dry so the grease won't migrate into your speedo and screw it up. So prefer oil to grease. That's up to you.

regards,
Rob

 

Im guessing a small screwdriver in there will work to see if the gear works. Unfortunately, I dont have a center stand on the bike so I may have to buy a motorcycle jack to spin the wheel. I already greased the cable all the way up with gear oil, I suppose I am now going to take it out and get some of the gear oil off the last 6 inches or so.

 

speedo drive



You can insert a small screwdiver or similar and just roll the bike for 10 ft or so to determine whether it's rotating. Speedo drives fail on a high percentage of bikes due to their poor metal construction, but it's your only option. They will last with good care. Mis-aligning the rear axle components when mounting a tire is a common reason for failure. A buddy can help set the bike on a concrete block without a lot of effort. Bob

 

Well ill get on it tomorrow and see if it indeed rotates. Then I will report back. If not, where to find the repros? Do they look like the orginals at least?

 

60-3213 or 99-9990 speedo drive



http://smmotorco.com/index.php?main_page=product_info&cPath=5&products_id=215 The usual price is $90-95 most places. This is one item that "made in Taiwan" is not a downgrade. part # 60-3213 E-bay has them. They are all the same, if you want to shop for the best price. They should cost $6, but at least you can get them. Bob

 

Is it a good idea or even possible to rebuild these guys?

 

rebuilding a speedo drive



There are 2 common problems with speedometer drives: 1, the worm drive is worn. You can shim the worm drive slightly to improve contact.(thin brass shim Ace Hardware maybe .002) This is unlikely to be successful for long. It is difficult to replace the nose piece to stay solidly in place.(press or interference fit). I used a nail set to crimp it in place. There is too much wear in the soft metal. 2, the lugs are broken off from mis-alignment. I soldered a couple of 1/4" pieces of #8 screw in place of the broken pot-metal lugs that engage the slots in the cylindrical bearing locator. You have to pry off the piece with the writing on it (toward the wheel) and later, bend it to get it to stay on. I have one like this that has lasted for years. I don't recall that the successful repair was on the first attempt. I had 2 drives to make one good one. Cleaning the gears might allow better engagement but only works with minimal drag from the cable; routing and lubrication are critical. I only tried this to find whether the speedometer worked at all---and it did. It is one of those nothing-to-lose deals. It might be worth a try to manipulate the soft metal. I never assume that the mileage on a Triumph is correct because this problem is so prevalent along with the instrument itself. Bob

 

they're all over ebay straight from india fo $20...make sure its not the plastic one as the link for $79 seems to be...if you buy them from a bike shop you'll be getting exactly the same thing with a 200+% markup for the middle man...you may have to ream out the axle hole.
Ive been told for the keen you can put the guts out of these into the original casing but havent done it myself

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=250749227895&ssPageName=STRK:MEWNX:IT

 

I'm full of it--again

I was not aware of the Indian-made or plastic speedometer drives, so I guess they are not all the same. Plewsy has a higher opinion of the Smiths drive. I wore out 3 of them, but I guess that is 35k miles each. I guess they lasted as long as the cables did. I do NOT have a high opinion of Indian parts. Chinese parts are better---I never thought I'd say that. But we called Hondas Jap-crap way back when. Bob

 

I believe my ratio is a 1:25. The one on that link is a 2:0. Id have to get my $150 new to me speedo reconfigured. I really dont want to do that. I found another online that is a genuine Smiths one. Ill snipe that one if it is indeed what I need to make this speedo work.

 

Ask lots of questions about the internal condition of that gearbox. You could be buying somebody else's junk. Ebay sellers are notorious for not taking stuff apart. The love to hide behind "used part, as-is, condition unknown", etc and then asking top dollar because the part is hard to find.

Nobody will ever notice if you have a Taiwan gear box. They look identical, only missing the Smiths markings on the case.

regards,
Rob

 

http://www.burtonbikebits.net/speedo_drive_gearboxes.htm

 

Yes it's a lesson to be learned. Don't buy secondhand speedo drives!

 

What`s the point of asking a dishonest seller questions?Do you think they are suddenly going to start telling the truth because you took the time to ask?

Rule #1 in business,always assume the other guy is trying to rip you off!

 

One of the saving graces of ebay is if the product is misrepresented, you can make a claim and get your money back. This pretty much reduces a lot of false advertising. Granted, one man's "good shape" is another man's "trash", but that could always be argued because their are published definitions for vehicular conditions that could be used for parts as well.

But if you take a vague description without asking for detailed questions, photos, etc., then you bought a pig in a poke and have no redress.

This is not about being naive, it's about protecting yourself. Buyer beware is the mantra. But that should not mean never take a chance. It means do your homework, get substantiation in writing, make sure you have a course of action should the product be misrepresented and if you feel you can buy with confidence of not losing in the long run, make the decision. It's about being smarter than the other guy, but never assuming he's an idiot.

regards,
Rob

 

I'm working on an electronic system that would house a small stepper motor inside the speedo housing to move the needle controlled by speed data from a magnet and sensor on the rear or front wheel. Then I can throw away the bl**dy speedo drive and cable, horrible things.
Just my opinion

 

Well as it turns out my drive seems to be ok. I did the screwdriver test and lo and behold it turns! I then took a look at the new cable i bought and realized the interior wire wasnt long enough to reach the inside of the gear. I bought it local so I traded it in for a correct cable and now it works! Thanks to everyone for their 2 cents. I really appreciate it.

 

Happens to the best of us. Glad you solved your problem without breaking the bank.

I would suggest that you lube that gear box with fresh grease. New lube sure can't hurt. It's good insurance for a valuable and unreplaceable (original that is) part.

regards,
Rob

 

The nipple sure looks small. Would a couple of good squirts of gear oil into the front (where the cable goes in) do the trick??

 

Not really. You want to lube the gears, not just the bearings. Grease is best because the gears put a shear force on the lube.

If it were mine, I'd remove the gearbox, pop the cover off of it, clean it really well, then repack it. Remember, we are talking about a 40 year old bike here. Chances are it's never been done before.

Grease and your time are cheap. New gearboxes are expensive.

regards,
Rob

 

If you stick toothpick or whatever in the front you`ll see that it`s a blind hole.