Speedo Drive Failure - Again

I know that this topic has come up before but I'm really getting frustrated with my speedo drives. Expensive and seem to fail after a few hundred/thousand miles. I've replaced two in the last 3 years and just had another failure today. Or at least I think its the same since I haven't had a chance to test the clock yet - I know run the cable anti-clockwise.

Has anyone ever figured out why they seem to fail? Is there anything short of not having a speedo that can be done to prevent failure? I really like having a speedo, if for nothing else than I like to know how many miles I'm putting on the bike.

What is failing in them ?

They need to be fully greased inside to continue to function.
Any metal to metal dry contact is death.
If your speedo cable is dry, or the cable run is kinked can put a lot of pressure on them too.

Parts quality is probably an issue here too. Even back then speedos often had a limited life,
a few road tests back then already record the odd failure, even when near brand new.

I still have the original cable and I don't recall ever greasing it... What part broke?? the drive or the cable?

Grease Smease its the weak holding ring of rivets that let the big gear get out of control then rest is history. Some are able to replace with screws than can be tightened to stay put but tedious to fit and relieve for clearances so some of us just shop ahead like tires or sprags. Some drives go away faster if the spacer top hat was left out so shell gets crush distortion.

Jim, I share your contempt for the speedo set up, so much so that I removed mine over 20 years ago.

I have seen a Norton rider go down when the cable ripped out of the drive and got tangled in the back wheel spokes.

There IS one very good and permanent solution, you can buy a digital speedo that look exactly like yours for around $300.

http://kullendesign.com/smithgaugewebsite/speedos/

1up3down said:

Jim, I share your contempt for the speedo set up, so much so that I removed mine over 20 years ago.

I have seen a Norton rider go down when the cable ripped out of the drive and got tangled in the back wheel spokes.

There IS one very good and permanent solution, you can buy a digital speedo that look exactly like yours for around $300.

http://kullendesign.com/smithgaugewebsite/speedos/

Click to expand...

How can this be a solution if your still stuck with the same old drive.

How can this be a solution if your still stuck with the same old drive.

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you are not, the old drive is gone forever

the digital speedo reads off a sensor glued to the wheel as it rotates

read more here

http://kullendesign.com/smithgaugewebsite/speedos/

1up3down said:

How can this be a solution if your still stuck with the same old drive.

Click to expand...

you are not, the old drive is gone forever

the digital speedo reads off a sensor glued to the wheel as it rotates

read more here

http://kullendesign.com/smithgaugewebsite/speedos/

Click to expand...

What about the Hall Effect unit?

pete.v said:

1up3down said:

How can this be a solution if your still stuck with the same old drive.

Click to expand...

you are not, the old drive is gone forever

the digital speedo reads off a sensor glued to the wheel as it rotates

read more here

http://kullendesign.com/smithgaugewebsite/speedos/

Click to expand...

What about the Hall Effect unit?

Click to expand...

Smiths' "Speedometer gets it’s signal from either a hall effect sender attached to your stock gear drive (ratio and wheel size doesn’t matter) for an “original look” or reed sensor (similar to a bicycle gauge) that can pick up from the sprocket, disc carrier or spokes *not included-see accessories."

I worked with Jim Comstock for quite a while to come up with a viable solution that still maintains the stock look (and spacing) of the original Smiths speedo drive for the very reason listed here and his design is brilliant. The conversion kit gives you four rare earth magnets spinning in a custom CNC machined reluctor triggering a Ruthenium contact reed switch tested at over a billion pulses. This also makes for a very smooth signal. The design allows you to totally gut the inside of the drive yourself (I recently did a batch of 20 of them to send them to powder coat) thereby eliminating any internal mechanical gears etc. I can dismantle one now in several minutes but what takes time, depending on how fussy you are is cleaning out the old grease, bead blasting, powder coating the housing and polishing the brass end cap. If you were to simply throw it in the solvent tank and hit it with some silver paint, you could probably do the whole conversion in less than 20 minutes. I offer the conversion kit and a conversion service including having housings with different size axle holes available for various British bikes, but the process I do is much more labor intensive. If you are interested, Motorcycle Classics Magazine just did a 3 page conversion article in their May/June 2015 Magazine on a newer Royal Enfield but using the Smiths electronic Chronometric speedometer which is a bit pricier than the Green Globe, Green Dot and NVT speedometers I offer for the Norton’s. There is a how to conversion video on our website as well:

http://kullendesign.com/smithgaugewebsi ... sion-kits/

http://kullendesign.com/smithgaugewebsite/accessories/

Cheers,

Tom Kullen
http://www.smithsgaugesusa.com

I appreciate all the info. It looks like in the long run the way to go is with the conversion. A bit pricey but so is replacing the speedo drive (last one I bought was $125K). I now am the proud owner of three. So in the period if I replaced with the conversion I would have a working speedo and be about even.

Getting ready to move from NH to Alabama, so will probably put off as a winter project. With the exception of needing to replace the rear rim, when the tire is worn down, the speedo is the only thing that has a problem. Crossing my fingers on the tachoometer which has gone through 3 cables since 2010.

JimR said:

Crossing my fingers on the tachoometer which has gone through 3 cables since 2010.

Click to expand...

Taking cables out and greasing them used to be on the Norton list of regular maintenance items.
Although out of fashion these days. Unless you pay a mechanic to do these things, unseen.

As soon as they run dry and put a big load on things, then blamo ! somewhere in the system.

JimR said:

I appreciate all the info. It looks like in the long run the way to go is with the conversion. A bit pricey but so is replacing the speedo drive (last one I bought was $125K). I now am the proud owner of three. So in the period if I replaced with the conversion I would have a working speedo and be about even.

Getting ready to move from NH to Alabama, so will probably put off as a winter project. With the exception of needing to replace the rear rim, when the tire is worn down, the speedo is the only thing that has a problem. Crossing my fingers on the tachoometer which has gone through 3 cables since 2010.

Click to expand...

Hi JimR.
Another way to skin your cat.
I still retain the mechanical speedo in the holder for looks but use a GPS speedo app on my phone (cost AUD$1.99).
The phone fits between the gauges and is powered through a charger. Locally, there is only one short tunnel so I guess for 30 seconds and don't twist the throttle.
Ta.

JimR said:

I appreciate all the info. It looks like in the long run the way to go is with the conversion. A bit pricey but so is replacing the speedo drive (last one I bought was $125K). I now am the proud owner of three. So in the period if I replaced with the conversion I would have a working speedo and be about even.

Getting ready to move from NH to Alabama, so will probably put off as a winter project. With the exception of needing to replace the rear rim, when the tire is worn down, the speedo is the only thing that has a problem. Crossing my fingers on the tachoometer which has gone through 3 cables since 2010.

Click to expand...

Yeah, by the time you have a tacho or speedo repaired plus shipping/insurance both ways you can easily be at least $150.00-$200.00 plus a pop and possibly another rebuild in a couple of years depending on use. Add to that replacing cables and/or the speedometer drive you can easily surpass the price of a new electronic unit. On top of that the LED lighting makes it so you can actually read it at night for aging eyes. :shock: Interesting note that one of the judges came by my booth at the Clubman Show in San Jose and said that if he hadn't looked at the speedometer closely at the booth to see the black out window for the odometer/tripmeter, he wouldn't have been able to tell it was a new Smiths electronic gauge.

Cheers,

Tom Kullen
tom@smithsgaugesusa.com
http://www.smithsgaugesusa.com