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Post by De Graaf van Salland on Mar 20, 2010 8:30:15 GMT 1
Now the good weather has returned, I frequently ride to work on my trusty NTV.  I have noticed that at higher speeds (± 100 km/h) the needle of the speedometer doesn't stay still in one place. But it swings a bit around the correct speed.  Any idea what could be the cause ? Should I lubricate the speedometer cable ? GvS |
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Post by McF on Mar 20, 2010 9:01:57 GMT 1
Should I lubricate the speedometer cable ? It won't cause any harm to lubricate the cable and it's a simple job to do. Grub screw retains the bottom end of the cable into the speedometer drive on the front wheel. Take a little care removing it because the plastic tab on the end of the cable can get brittle and may snap. The mild steel screw is likely to be rusted and covered in road dirt. Withdraw the outer cable from the speedo drive, then slide the inner cable out - no need to remove the top end from the speedo. Give the cable a clean and note if there feels like any small particles of grit or rust etc. The cable only needs a light film of oil. I would get a rubber glove (or a plastic bag over my hand) put some (say 10ml) oil in the palm and then wipe it up and down the cable. Avoid using a cloth as bits of fibre can stick to the cable. Slide the inner back into the outer cable, you may need to use a flat blade screw driver to rotate the cable and slot into the speedo at the top, then put the lower end back into the speedo drive - you may need to rotate the inner cable again, or the front wheel to get the alignment right. Grub screw to retain and that's job done - 30 minutes. Hopefully that will cure it. If not, I would remove the front wheel and take a good look at the inside of the speedo drive. Give it a good clean inside and check the flat drive plate - there should be two "tabs" that engage with the wheel and two into the worm gear. These do flatten over time. Carefully bend them back a little if they aren't properly engaging - this could take 1 - 2 hours. The worst case scenario is the magnetic drive inside the speedo. The cable is not directly connected to the speedo needle, but a magnet. Another magnet on the back of the needle spins with this magnet and moves the needle. One magnet is a "cup", the other a "plug" inside it - I forget which way is which, but suspect the "Cup" is the top of the cable. The mileage is directly connected to the cable. It is possible and fairly straightforward to strip the speedo down and clean this all up and check it is not fouling, but it's a fiddly job and likely to involve aged brittle plastic which easily falls apart. Unless the speedo has been mechanically damaged, I doubt this is the cause. Time would be in excess of 2 hours depending on how stubborn the little screws etc are. Good luck; I'm sure all of this in easily in your capability. I look forward to the progress report and no doubt some pictures! |
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Post by rj2para (Bisto) on Mar 20, 2010 17:51:12 GMT 1
Mine did exactly the same before it snapped, about 100-150mm up from where it joins the wheel. Good luck. (The yellow circle shows where mine snapped)  |
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Post by De Graaf van Salland on Mar 21, 2010 8:16:31 GMT 1
Thanks McF for your excellent "How to ..."
And thanks RJ for the warning.
I will definitely have a look at the cable soon.
GvS
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Post by De Graaf van Salland on Apr 3, 2010 21:06:27 GMT 1
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Post by McF on Apr 4, 2010 7:28:46 GMT 1
Great news, well done and presumably a quick job? Was it obviously dry and rusty? |
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Post by De Graaf van Salland on Apr 4, 2010 8:47:40 GMT 1
Great news, well done and presumably a quick job? Probably only 30 min. (Most of the time taking photo's) But if I had to do it again, it would take only ±10min. Was it obviously dry and rusty? No, not really. But the cable isn't really a cable. It's more like a very long coil spring. If you would stretch the spring (don't !), it would probably be ±5 mtr long. At the bottom, near the front axle, the input of the cable is a steady number of rpm. (if riding a constant speed). The output (at the top of the cable) should be the same (steady) rpm. With that length of cable, any small bit of dirt of dry spot would cause the number of rpm at the top end, to become unstable. GvS |
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odie
Bad ass biker
Posts: 263
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Post by odie on Apr 11, 2010 16:22:19 GMT 1
DO NOT USE OIL ON THE CABLE!
You use graphite powder, oil will clog it up and make it read slower!
Also, using oil, it can spread up the cable and into the speedo head, not good as it can really f**k it up!
Odie
P.s.
Erratic reading means its about to snap, i replaced mine with one from a CX650 euro, any Honda speedo cable with the same end's and length will work so you don't need one specifically from an NTV
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