Tachometer Problems

[dubwicht]

Yesterday I replaced the tach cable and the two gaskets in the drive. I properly aligned the cable with the pin. The tach seems to show the idle speed but when I crank the throttle nothing happens. I was wondering why the slot in the cable seems to be larger than the pin on the drive - it didn't look right. However, I looked at several on Ebay and mine seems to be the correct drive unit. I am wondering if the drive is faulty. Has anyone had this issue? Perhaps I need a new Tach?

[Rich82GS750TZ]

You could remove the new cable knurled knob where it connects to the drive on the front of the head (or front of valve cover on some models) and take note if the rotation speed of the spindle increases w/ RPMs. It should. If it does, than your problem could be where your new cable screws into the back of the tach. The square end of the cable needs to be firmly inserted into the back of the tach spindle housing. I suppose it's possible that the female orifice had gotten rounded out.

This has to be done with the tach removed and turned upside-down:
If it's not rounded out and the orifice appears to be square, you could use a broken-off bit of square end of old tach cable or Robertson #1 square bit chucked in a drill, insert and run drill on reverse. A few drops of thin oil (3in1, or sewing machine oil works) in to the orifice helps. This can perk up a sticky tach. YMMV.

[dubwicht]

Thanks - I will give it a go!

[dubwicht]

Hello again. I inserted the end of a cable and used my drill to test the tach. It did work but so slowly that it took almost 30 seconds for the needle to register the correct RPM's. I think there is something wrong with the tach. It should register immediately.

[dubwicht]

This should fix it!

https://www.youtube.com/watch?v=VG0s9VB0H9c