Tach occassionally has a mind of it's own...

'79 KZ1000 LTD B - cable tach drive

Sometimes when I'm really getting on the throttle, the tach just sort of stops responding and starts doing what it wants. It is a brand new cable. I don't know if it used to do this before I replaced the cable, because I replaced a cable that was broken in two. This is how it was when I bought the bike.

More descriptive here... I'll get around 7-8K rpm, and the tach will just sort of float around the 7K mark before I shift up. When I do shift up and get back on the power, it does it again right around 7K. Sort of seems like the cable is not being turned, but the drive for it (after the gear) is just spinning around the square end of the cable. If the engine speed is less than 7K, and throttle is less than 100% it doesn't do it.

Anybody know what's going on here?

unless there is a reason that the cable is not staying in good contact with the drive ends, both at the engine and the tach, then I think the tach may be bad

ive seen some tach goofiness caused by people including myself replacing the rubber grommets or tightening them up with washers. if the tach or even speedo isnt mounted properly with rubber mounts it can do some really weird stuff. make sure it isnt mounted too tightly to the base. the rubber grommets get old and shrink and i tried washers to tighten them up somewhat. it doesnt work too good. check that first...steve

I'd remove the inner drive cable from the tach cable and look for broken wires or burrs as these will cause strange readings. Relube the cable and put it back in the tach cable housing,fire it up and see any difference.

Would assure correct fitment of tach cable to tach.

As known, the flanged cable end fits against the tach, and is supposed to be held snugly in position by tightening the knurled cable nut (female threads) onto the tach (male threads).

If the knurled cable nut is cross-threaded or only partially screwed onto the tach, the nut won't tighten as required, which prevents the inner cable from correctly fitting into the tach.

Good Luck!

Thanks for the suggestions! Will investigate tomorrow.