Why do I keep breaking speedo cables?

[radbrad]

82 650G - I've haven't had this bike too long and had only ever previously removed the speedo cable from the wheel, in order to clean it to stop the vibrating/noise it sometimes makes up at the speedometer. Started vibrating again and this time decided to remove the cable from both ends to do a better job cleaning and lubing. Put it back together, got no response in the speedometer, discovered the cable broke at the wheel - the female end piece that fits into the tooth at the wheel was snapped off.

Got a new cable, put in on and the same thing happened, twisted that end piece right off from the rest of the cable. I'm trying to figure out what I did wrong. Here is how I installed the new cable -
- inserted the top part into the speedometer and tightened it up part way
- from the bottom, pushed the cable all the way into the outer cable, the female end piece was about even with the end of the outer cable.
- tightened the top up all the way
- fit the bottom onto the gear tooth
- tightened the bottom
---- tried to ride and heard it break, as I described above.

Can anyone tell me what to do differently next time, I ordered another cable. It seems like my problem may be fitting it in the speedometer end, how do I tell if it is fit right up there, it is just a hole you push it up into?
The way it snapped indicates that it was fitted correctly at the bottom, but didn't move when twisted by the gear - so must be fitted incorrectly at the top.

Thanks for your advice guys.

- Brad

 

[crapwacker]

I would but the lower part together first, and then instal it into the speedo. the speedo end is square, if it's like mine, and this way you can move the wheel and verify that the cable is turning before putting it into the speedo. If it won't seat into the speedo, move the wheel to rotate the cable until it will go in. Hope this helps

 

[Redman]

Brad,

Yes, Install on wheel first, (notice how the cable end is a flat tab, and the wheel unit has a slot) try turning the cable with your fingers on the other end as you put the cable in place so that the tab lines up with the slot in the wheel unit, you can then feel when the tab lines up with the slot.

Then install the speedo end while spinning the wheel to make the cable turn.

.

 

[radbrad]

OK guys, thanks -

I could install the bottom end, and with the cable sticking out of the top, roll the bike to see if it rotates, and if it does, shove it up in the speedometer and lock it down - right? I am concerned that it could come undone from the bottom rather easily though, so I would just have to carefully insert it into the speedometer and screw it in, making sure not to pull up on the inner cable... is that what you guys are pretty much saying?
--- but how do I install the speedo end WHILE spinning the wheel, are you saying I could get the wheel in the air and actually be spinning it as I put it up in the speedo?

thanks

Brad

 

[seuadr]

OK guys, thanks -

I could install the bottom end, and with the cable sticking out of the top, roll the bike to see if it rotates, and if it does, shove it up in the speedometer and lock it down - right? I am concerned that it could come undone from the bottom rather easily though, so I would just have to carefully insert it into the speedometer and screw it in, making sure not to pull up on the inner cable... is that what you guys are pretty much saying?
--- but how do I install the speedo end WHILE spinning the wheel, are you saying I could get the wheel in the air and actually be spinning it as I put it up in the speedo?

thanks

Brad

spin it very slow, as the hole for the square end is also square, will help you mate it up.

 

[radbrad]

still stuck, need help! I got the new cable, installed the bottom end, I could see it rotating as I push the bike forward, I am able to seat it into the speedometer but once it is in there the cable does not seem to rotate when I push the bike forward! Is this normal?

I'm afraid that after I go a few yards it will snap from overtension. I am pretty sure it is in the speedometer right, because if I try in insert at a different angle it sort of gets stuck half way.

please help thanks!
- Brad

 

[Texas Don]

Reverse the process. Install the upper end into the speedometer first. Then see if you can turn the lower end with a screwdriver. Gently. If so, then your speedometer may not be at fault. You won't be able to turn the cable by hand fast enough to cause your speedometer to register. You can only feel for rough spots as the cable turns or abnormal resistance. If not, then you've got a speedometer going south on you. Breaking cables is not normal so you've got a problem in either the drive or the speedometer.
Don

 

[radbrad]

tried this

tried this

Reverse the process. Install the upper end into the speedometer first. Then see if you can turn the lower end with a screwdriver. Gently. If so, then your speedometer may not be at fault. You won't be able to turn the cable by hand fast enough to cause your speedometer to register. You can only feel for rough spots as the cable turns or abnormal resistance. If not, then you've got a speedometer going south on you. Breaking cables is not normal so you've got a problem in either the drive or the speedometer.
Don

Texas Don,

Thanks, I just tried this, and I wasn't able to rotate the cable, I twisted it a few notches and it built up tension in the cable, then I let go of the screw driver and the cable twisted back to normal. Am I supposed to be able to rotate this cable easily, or is is supposed to get tensed up first before it rotates in the speedometer? there is definitely no problem with the drive end

- Brad

 

[Steve]

The cable won't keep spinning freely when you let go of it, but it should not be any harder to turn when inserted into the speedometer.

.

 

[radbrad]

it's just stuck then

it's just stuck then

The cable won't keep spinning freely when you let go of it, but it should not be any harder to turn when inserted into the speedometer.

.

Thanks Steve, if that is true, then I have a problem inside my speedometer. Anyone else ever experience a cable that jams in the speedometer like this?

The only thing I did to it was remove the cable for cleaning, and sprayed a squirt of wd-40 as well as a dash of 3 in 1 oil up in there. I bet this is the first time the cable's been removed from the speedo in 25 years.

What now? Is it possible it is just not jammed up there far enough?

- Brad

 

[radbrad]

Any further advice before I start to take apart my speedo?

 

[Larry D]

Any further advice before I start to take apart my speedo?

Not a speedo, but, a tach. Follow the links and see if they help some. Same process, I suppose......take some pics of your progress. This comes up every so often and there's not many pics of this surgery.

http://www.thegsresources.com/_forum/showthread.php?t=146689

 

[radbrad]

what drill bit to use on speedo

what drill bit to use on speedo

I would like to try putting a drill bit which resembles the end of the speedo cable, up into the speedo to see if I could get it unstuck. Could anyone tell me exactly what to use that will match the square end of the speedo cable on my 82 650G?

Thanks

 

[reddirtrider]

I would like to try putting a drill bit which resembles the end of the speedo cable, up into the speedo to see if I could get it unstuck. Could anyone tell me exactly what to use that will match the square end of the speedo cable on my 82 650G?

Thanks

You're probably more likely to break something doing it that way. Take off the intrument cluster, pull the speedo, and see what's wrong. Brute force isn't likely to fix it.

 

[Texas Don]

The conditions that you describe are definitely not normal. I've never actually seen the inside of a speedometer on a bike, but if they're built like cars, then you have a series of gears that drive the speedometer and the odometer. You have something jammed in the speedometer for sure. Don't try brute force unless you're ready to purchase another speedometer and yet another new cable. Did you try resetting the odometer to zero? Occasionally they get jammed in between numerical resets and can cause some issues. One thing's for sure. You can't use it the way it is so you may as well take it apart slowly and carefully and see if you can discover the cause of the failure. You might want to consider taking it to a professional speedometer repair shop. Do they still exist anymore?
Don

 

[radbrad]

odometer

odometer

The conditions that you describe are definitely not normal. I've never actually seen the inside of a speedometer on a bike, but if they're built like cars, then you have a series of gears that drive the speedometer and the odometer. You have something jammed in the speedometer for sure. Don't try brute force unless you're ready to purchase another speedometer and yet another new cable. Did you try resetting the odometer to zero? Occasionally they get jammed in between numerical resets and can cause some issues. One thing's for sure. You can't use it the way it is so you may as well take it apart slowly and carefully and see if you can discover the cause of the failure. You might want to consider taking it to a professional speedometer repair shop. Do they still exist anymore?
Don

Yeah I tried resetting the odometer to zero, and spun around to different numbers just to see if it made a difference, it didn't seem to.

 

[radbrad]

From what I'm reading, fixing a busted speedometer head is not easy, I'm going to post in the parts wanted section for a new speedo for the 82 650G, let me know if anyone has one they want to sell. I probably will cut this thing open, I'll take pics and post them when I do.

thanks

 

[Redman]

I dont now if you said how soon the cable breaks and if the speedo does work before the cable breaks.

BUt:

One way that I tested a speedo:
- I looked into the speedo where the cable fits, and noticed that the square hole was about the size of a wooden match stick. So I got a wooden match stick and used a drill motor (varaible speed) to drive the speedo, slowly start it and slowly speed it up (trying not to shear the matchstick).

- Or.... if you still have have a broken cable available, maybe you could take the end of that instead.

.

<<later note>>>
Oh, now I see your post about how it seems that the speedo unit is bound up. So you already know what I am suggesting you test to determine.
I dont have any experience with a bound up speedo.
.

 

[radbrad]

well...

well...

I dont now if you said how soon the cable breaks and if the speedo does work before the cable breaks.

BUt:

One way that I tested a speedo:
- I looked into the speedo where the cable fits, and noticed that the square hole was about the size of a wooden match stick. So I got a wooden match stick and used a drill motor (varaible speed) to drive the speedo, slowly start it and slowly speed it up (trying not to shear the matchstick).

- Or.... if you still have have a broken cable available, maybe you could take the end of that instead.

.

<<later note>>>
Oh, now I see your post about how it seems that the speedo unit is bound up. So you already know what I am suggesting you test to determine.
I dont have any experience with a bound up speedo.
.

Well, what I did was take the speedo off of the bike, got the end of the cable and stuck it in there and tried hard to rotate it by hand - it wouldn't move at all. I put some lubricating oil in there and letting it sit overnight but I doubt that will do anything.

What I think happened here was that something broke as I removed the cable. It had been bouncing around in there a occasionally, it probably got damaged from doing that too much. When it was bouncing and buzzing, I could bang the top of the speedometer to stop the buzzing, I'm sure that didn't help! ha!

- Brad