Jumpy Speedometer

[LowRyter]

thanks for the link Doc. Looking at the photos, I need to take the elbow n the transmission connection apart? make sure the gears are ok and meshing.

[docc]

Can you see the brass insert coming apart? Otherwise, not a bad idea to disassemble, inspect, and lube. The lube adds pressure and makes the metal disc more likely to spit out along with the lower gear. The epoxy is good measure and can be removed with a Dremel if needed.

 

There are two anchor points to each bevel drive (four in all). If any of them rotate, the needle will wag.

 

That said, and all I have done, the needle does still does wag at lowest speeds.

[LowRyter]

I've serviced both ends of the cable. I lubed it, tightened those two screws on the speedo unit, taken the tranny drive off, it moved freely and the brass fitting is tight. I did get it all back together after taking it apart & it all still works about the same. Since the previous owner did top maintenance, I'm not surprised that I didn't find a quick fix.

 

I am bothered that the lube seeps out the cable at the connection at the tranny drive.

 

It gave me an opportunity to putter around on it, I did no apparent harm. It's minor nigle for now (knock wood).

[luhbo]

You're dealing with the cheapest Veglia units they ever made, the working principle is a hundred years old probably. You have a rotating magneto working against a single clock type spring. Together with a more than cheap-don't-know-what-damping gimmick at one end of the needle's axis it has to wag. Some do it more, some do it less. That's rather typical for cheap devices.

Hubert

[motowarren]

Here's a link to the thread Speedo Needle Wobble showing a picture of the space that can develop in the lower bevel drive as its mounting pulls apart.

 

The two screws on the upper hold the bevel drive to the back of the speedometer and can only be seen with the instrument pulled out of its case.

Did you ever find out where that washer goes? I'm also having similar speedo problems. I have the gearbox angle drive apart and in addition to the problem areas you mention I notice the inner dia. of the brass bushing is pretty well worn. It's actually oval shaped and about .015 in out of round. I'm sure the would have something to do with needle wobble. My bike has 43k miles. I think it would probably be worthwhile for me to make a new sleeve for the bushing.

[jrt]

OK, so this is a bit tangential to the subject. Given that the speedo gears are not readily obtainable, but made of plastic, wouldn't these be a good candidate for 3D printing?

Anybody have a 3D printer? I'm keen to get one, but I can't quite justify it.

[luhbo]

... It's actually oval shaped and about .015 in out of round. I'm sure the would have something to do with needle wobble. My bike has 43k miles. I think it would probably be worthwhile for me to make a new sleeve for the bushing.

 

Be careful when you pull this assy apart. The tiny shaft brakes easily.

Hubert

[Kiwi_Roy]

The main odometer on mine gave out at about 70,000 km, the plastic gear stripped.

I was able to swap it for the one out of the trip odo.

The old gear still has enough grip to run the trip, less load with fewer wheels to drive.

 

I think the main reason the needle wavers is a kink in the inner cable causes the magnet to change speed slightly.

[Skeeve]

OK, so this is a bit tangential to the subject. Given that the speedo gears are not readily obtainable, but made of plastic, wouldn't these be a good candidate for 3D printing?

Anybody have a 3D printer? I'm keen to get one, but I can't quite justify it.

 

Gears need to have smoooth surfaces to mesh & xfer power properly. 3D printing doesn't really get that fine until you're talking megabucks.

 

Wait for it, Weedhoppa: it'll come, it'll come. Maybe not soon, but someday...

[docc]

Here's a link to the thread Speedo Needle Wobble showing a picture of the space that can develop in the lower bevel drive as its mounting pulls apart.

 

The two screws on the upper hold the bevel drive to the back of the speedometer and can only be seen with the instrument pulled out of its case.

Did you ever find out where that washer goes? I'm also having similar speedo problems. I have the gearbox angle drive apart and in addition to the problem areas you mention I notice the inner dia. of the brass bushing is pretty well worn. It's actually oval shaped and about .015 in out of round. I'm sure the would have something to do with needle wobble. My bike has 43k miles. I think it would probably be worthwhile for me to make a new sleeve for the bushing.

 

Turns out, the washer fits nicely in a small container on the shelf labeled, "Washers and other parts left over from reassembly."

[Tom M]

I think the main reason the needle wavers is a kink in the inner cable causes the magnet to change speed slightly.

 

I hoped that was the case when I replaced my cable last year. It wasn't.

[Kiwi_Roy]

I think the main reason the needle wavers is a kink in the inner cable causes the magnet to change speed slightly.

 

I hoped that was the case when I replaced my cable last year. It wasn't.

The tach on my California had a waver when I bought it last year, sure enough the cable snapped on my trip to California

 

I wonder if the waver is also caused by the gears getting ready to go crunch and loading up the drive at various points in rotation

[Tom M]

I think the main reason the needle wavers is a kink in the inner cable causes the magnet to change speed slightly.

 

I hoped that was the case when I replaced my cable last year. It wasn't.

The tach on my California had a waver when I bought it last year, sure enough the cable snapped on my trip to California

 

I wonder if the waver is also caused by the gears getting ready to go crunch and loading up the drive at various points in rotation

 

In my case it's either the upper angle drive or the speedo itself since the lower angle drive and the cable are new.

 

I took the speedo apart a couple years back when it started misbehaving and didn't see anything that was obviously wearing out in there. I'm going to live with the wag for now, might get back after it next year.

[AndyH]

 

I use white grease with PTFE - does the job OK. Pull out the inner and really grease it up. It really isn't worth losing the transmission end nylon gears, not exactly unobtainable but eye wateringly expensive for a bit of plastic. If you do need to replace the 60 deg gearbox at the lower end you can convert the 'obtainable but equally expensive' one at the clock end using the metal adaptor insert from the knackered one - see my recent post elsewhere

Andy

Oh the Hubris!!

 

Shortly after writing this my needle started jumping around; dutifully I lubed the inner once again with white grease/PTFE (you'll find this method suggested elsewhere in the forum). Just this morning (3 weeks later) the needle starts bouncing around with gay abandon, 5 mins later reads only ~ 60 mph (+-10mph), then 5 mins later nothing - all in the space of 45 miles.

 

The cable is new this year, the run is about as straight as it can be, it's been lubed to hell, the 60 deg gearbox is new out of the packet this year - total mileage achieved before self-destruction: 4000 miles.

 

Good thing I have two more 60 deg gearboxes in stock... looks like I'll need them to cover another 8000 miles.

 

AndyH

[AndyH]

Just this morning (3 weeks later) the needle starts bouncing around with gay abandon, 5 mins later reads only ~ 60 mph (+-10mph), then 5 mins later nothing - all in the space of 45 miles.

 

The cable is new this year, the run is about as straight as it can be, it's been lubed to hell, the 60 deg gearbox is new out of the packet this year - total mileage achieved before self-destruction: 4000 miles.

 

Good thing I have two more 60 deg gearboxes in stock... looks like I'll need them to cover another 8000 miles.

 

AndyH

The cable is absolutely fine - I can turn the inner with my fingers and get a blip on the speedo: that wouldn't happen if it was binding. But sure enough, 60 deg gearbox nylon gears are mashed: they engage OK when turned by hand with no resistance but under any resistance at all they jump teeth.

Why nylon gears? What was Luigi thinking?

I'd happily pay more for one with metal gears if it was going to last 20+K miles.

 

AndyH