place a small screwdriver in the end of the drive and either kick the bike over or rotate the wheel. See if the screwdriver rotates. You might need to do it several times to make sure that the driver is in fact in the correct position.
If it does rotate, then the drive is ok.
Refit to the drive and stick a small flag of tape on the dial drive end of the cable so that when you do the same test, it's easy to see the square drive rotate.
Either it will, or won't but either way you'll find the problem
You can test the gauges by putting a small screwdrive in the square drive socket and spin it with your fingers. If the needle moves, you can go to an electric drill to see if it moves uniformly.
If your cables are seized, rusted, packed with crud or broken and jammed up, they could have destroyed the gear in the speedo drive and the little sheetmetal drive in the cam for the tach.
There are multiple failure points on both the tach and speedo systems. So asking what's wrong will only result in a list of potential causing. And it could be more than one at play. For example, your cable housing could be crushed and this caused the drive core to chafe. It started to unravel and catch on the housing. When it would catch it would put stress on the drive gear teeth. Eventually the cable snags and seizes and the overstressed teeth fail. So you now need a new cable/core assembly and a new drive gear assembly. That's why my first order of business for a newly purchased bike is inspecting the speedo and tach cables, cleaning and lubing them and replacing if necessary before they do more damage to related parts.
To beat this a bit more, I had a cable that would snag, wind up like a spring and then release. Speedo would go from zero to max in an instant. Although that speedo still works, I'm sure it did not do it any good. I did stop along the roadside and disconnected the cable from the speedo. I should have pulled the core out too, but it was probably too late by then anyway.
Hi, So I've nearly reached the total the end of my strip down of my 71 T120 right down to separating the crank cases,sludge trap etc.I know nothing of possible improvements and must do's on the re-build. Any chance of some definitely do this pointers please. Thanks
I have an '87 Harris T140V, and the gearbox drain plug is knackered - the thread has partly split away from the bolt head, and it leaks. I'm guessing that some insensitive fool over-tightened it last time I changed the oil. No idea who that could be, but what torque setting would be...
Hi, I have a 1961 T20 triumph tiger cub and looking to find out of there is a quick fix to improve the front brake. In the main when riding its the rear brake that slows the bike down as the front brake takes around a mile of road before stopping! Ive heard you can get a high brake cam lever...
I'm trying to change the fluids on my 1966 T120R that I bought a couple weeks ago. I cannot seem to locate the gearbox drain. I think it is the plug I've got indicated in the attached pictures, but I'm not sure. If this is the right plug, I cannot get a socket onto the outer nut because the...
As a Hinkley triple owner (don't hate me guys!) I sometimes also read the threads on that section of the Triumph Rat forum and they have a long running thread "what I did to my classic triple today" or something very similar. Posters put up a few lines about what they did with their 'bikes that...
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