TOPIC:

I just got my hands on a 79 kz650 B3, but the tachometer isn't working. I'm not yet that handy with bike maintenance so I'd appreciate some tips with this. It looks like there might be a small oil leak coming out of the engine where the cable goes in so I'm guessing that the least I need is a new cable. Do I start with that and see if the issue is resolved? Or will there be more to it than just a cable replacement?
Thanks in advance for any info.

Unscrew the cable from the bottom of the tach.
Start the engine.
If the inner cable is spinning, then it's working and the problem is in the tach itself.
If the inner cable isn't spinning, that means it could be broken.
There is a small washer that goes in bewteen the cable and the engine. If thats missing, that could be the cause of your oil leak.

Thanks,
I finally got to check the cable. The inner cable wasn't spinning so I ordered a new one. Hopefully that will sort out the tach and the oil leak.
Thanks again. I'll post once I get some results.

Welcome to the KZR Nation. I feel your pain... I just changed my broken Tach cable last week.

To stop the oil leak I/you need this Tach Oil Seal:


www.z1enterprises.com/detail.aspx?ID=1585

At under $3.00 USD it’s an inexpensive solution.

Best of success.

PS

Don't forget to add your year, model and location to your signature to get the best replies... and it’s considered very friendly too.

With properly fitted fresh seal and o-ring in the tach drive, no oil should escape from the engine head, even when the tach drive cable is not attached. In other words, the tach drive unit is supposed to be completely oil tight and leak-free without the tach cable being attached to it. Without the tach cable being attached, the end of the tach drive shaft may be seen spinning while the engine is running, but no oil whatever should be escaping from the tach drive unit.

Relying on an oil-tight fitment between the knurled knob on the end of the tach cable where the cable attaches to the drive unit (via sealant, o-ring, packing, etc.) is treating the symptom and not the cause, and doesn't cure the leak, but simply allows the "leaking" oil to run up inside the tach cable instead of down onto the engine cooling fins.

Good Luck!

Patton wrote:

With properly fitted fresh seal and o-ring in the tach drive, no oil should escape from the engine head, even when the tach drive cable is not attached. In other words, the tach drive unit is supposed to be completely oil tight and leak-free without the tach cable being attached to it. Without the tach cable being attached, the end of the tach drive shaft may be seen spinning while the engine is running, but no oil whatever should be escaping from the tach drive unit.

Relying on an oil-tight fitment between the knurled knob on the end of the tach cable where the cable attaches to the drive unit (via sealant, o-ring, packing, etc.) is treating the symptom and not the cause, and doesn't cure the leak, but simply allows the "leaking" oil to run up inside the tach cable instead of down onto the engine cooling fins.

Good Luck!

That's all true, however there are instances where replacing the seals are not possible, at least not possible that I could figure. On my KZ1000MKII that assembly is welded to the engine. I'm not kidding, no amount of heat/cold/prying/turning/whatever will budge that tach drive and it's been like that for 25 years at least. It started leaking, I opted for the gasket material readily available as cardboard cerial box type stuff, cut a gasket to seal the drive to the cable and 'voila, no leaks, plus the added lube to the tach cable always there

The tach is fixed. Thanks for everybody's input and thanks Bill for that link to the tach oil seal.
Now to work on my signature!