Tach/Cable Question

[Wheels24]

Dumb question of the day... Can I run my 1980 CBX with just the tach cable sheathing in place with no drive cable in it without risking any damage to the cable drive mechanism under the valve cover?

History: My CBX (59K miles) recently started the somewhat common tach "whine". I tried lubing the cable and shooting some lube into the tach's cable opening. Things were quiet for about 20 miles, then the whine returned, and after a few more miles the tach got erratic and then stopped working altogether.

I pulled the cable and discovered it was broken about 6" above where it attaches to the valve cover. I threw away the broken cable, kept the original sheathing, and ordered a new cable. I installed the new cable and the tach worked perfectly again, but after about 5 seconds the whine returned as loud as ever. Yes, I checked the new cable...it's well lubed. Must be the tach...

Sooo...not wanting to attempt to disassemble and service the tach at this time, I bought a new aftermarket tach on-line. What I didn't consider was how different the new tach would look sitting next to the (somewhat faded) original speedometer. Honestly, it would make me crazy every time I looked at it, and I have no need to buy a matching new speedometer.

What I'd rather do is leave the original tach in place and install the empty, original, sheath to keep dust and debris out of the tach cable's valve cover attachment point and the underside of the tach. With 59K+ miles on my CBX, I don't rev the daylights out of it and can obviously manage shifts by ear. I'd rather have visually matching instruments than a working tach...strange as that may sound. I'll keep the new tach in case I ever need to replace the speedometer as well.

My only concern is whether running just the empty sheath will do any damage to the drive components in the valve cover, or cause any leaks. I don't know if the split cable end that goes into the valve cover attachment point helps hold the components together or not. All input is welcome!

Thanks, and have a great Memorial Day weekend!

Gary

[Dynamohum]

You might get some oil up into the sheath but beyond that I can’t see anything that would harm the tach drive gear.