Jumpy Speedometer

[LowRyter]

Now that we've discussed the broken tach, does anyone have experience with the speedometer with needle jumping around? It goes up & down the scale tracking my speed, but it just jumps around plus & minus 5 mph. I know that I am in the right "zone" according to the speedo. So it's an approximation of my actual speed.

 

Am I right to think the speedo cable needs to be lubed or replaced or is this something else?

[fotoguzzi]

your right, or live w/it till it busts completely, that's what I'm doing..

[LowRyter]

your right, or live w/it till it busts completely, that's what I'm doing..

 

you're saying replace it after it breaks? lubrication is futile? (I don't how but assume that graphite application might work). Any idea what the cable costs and how long it takes to order?

[guzzimeister]

Hi

 

jumpy speedo is symptomatic of a dry cable. You must lube it or the strain imposed on the little plastic gearboxes at either end is enough to strip the gears. These are not repairable and nigh on unobtainable. The cable can be lubricated with a mixture of 3 in 1 or similar and WD40. Pull the cable out, drip the oil on it and wash most of it off with the WD40. It's been OK for 60000 miles with me.

 

Speedo drives come in two forms. One cable has a gearbox at each end, the later models have the speedo cable screwing straight into the gearbox vertically with no gearbox at that end. If your speedo drive gearbox is shagged at one end, suggest buying the later cable and takeing the drive straight off the gearbox. The SD gearboxes are identical.

 

Cheers

 

Guzz

[thumper]

Each time I change the trans fluid I pour a little synthetic trans oil down the cable housing.

Remove the cable from the back of the speedo, pull out the cable, clean and lube, reinstall.

[ponti_33609]

Each time I change the trans fluid I pour a little synthetic trans oil down the cable housing.

Remove the cable from the back of the speedo, pull out the cable, clean and lube, reinstall.

 

This method worked for mine!

[LowRyter]

so 3 in 1 or sometype of oil? Not grafite or dry lube?

 

and I just unscrew it from the speed unit, drip lube inside the cable and let gravity take it all the way to the tranny?

[ponti_33609]

so 3 in 1 or sometype of oil? Not grafite or dry lube?

 

and I just unscrew it from the speed unit, drip lube inside the cable and let gravity take it all the way to the tranny?

 

It ends up draining from the cable back into the tranny and why we typically do when changing the tranny fluid.

[docc]

If you have bevel drives, look for the lower drive to be separating from the housing. You will see the screw-on part pulling away from the plastic housing. This can be pressed back together in a vise or such after removal. Be certain the threaded connection is quite tight and does not rotate. Same for the screw down bale at the speedometer end - be certain it is tight and the bevel drive will not rotate. Finally (if you have bevel drives): be certain the "retaining disc" at the lower end is epoxied in place. If it spits out (like it might with too much cable lube), the internal gear will spit itself off into the greater universe.

extra moderatorism:

Folks - if you would please: go to your profile and add our bike's year/model. Also, most helpful to have some location in your profile, even if only continent - this really helps forum members narrow in on solutions!

[AndyH]

so 3 in 1 or sometype of oil? Not grafite or dry lube?

 

and I just unscrew it from the speed unit, drip lube inside the cable and let gravity take it all the way to the tranny?

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 unpbtainable 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

[LowRyter]

I lubed it with some teflon oil. didn't seem to make a difference. I think there might be something with the unit itself. It doesn't like to reset to zero when sitting still until it's shaken by the vibration of the engine.

[docc]

Did you press the lower unit back together and anchor the upper with the two slotted screws bearing down on the retention plate on back of the speedometer?

 

Also, be sure to torque the knurled collar holding the lower drive to the gearbox. There should be no rotation there.

 

Epoxy the metal disc before it spits out, especially if you have added a viscous lube in the housings.

[LowRyter]

Did you press the lower unit back together and anchor the upper with the two slotted screws bearing down on the retention plate on back of the speedometer?

 

Also, be sure to torque the knurled collar holding the lower drive to the gearbox. There should be no rotation there.

 

Epoxy the metal disc before it spits out, especially if you have added a viscous lube in the housings.

 

I didn't notice any additional screws on the speedo unit, I just unscrewed the cable & lubed it. Just checked the tranny end and the oil was dripping out. That doesn't seem right, I'd think the cable should be be sealed. I tightened the cable fastener, it wasn't lose but I did tighten it. The fitting of the transmission seemed tight. The leak was on the cable fastener not at the transmission mount.

 

didnt make a difference on the test ride.

[Kiwi_Roy]

There are no seals in the speedo cable, they have been that way forever.

 

Did you notice any kinks in the inner, that's a common cause of needle jump, it sort of winds up then lets go.

[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.