Is my tachometer dead?

[meri]

I just replaced the bulb in my tachometer. When I reattached the cable and started up the bike, I noticed that the needle rises very slowly. When it gets to higher RPMs it seems to be a little looser. I haven't seen a problem until today. Is it dead? Anything I can do to test it or fix it?

[BaltimoreGS]

Is it the old style mechanical tach or the newer electronic model?  If it's the old mechanically driven tach make sure you have the cable attached securely.

-Jessie

[meri]

Is it the old style mechanical tach or the newer electronic model?  If it's the old mechanically driven tach make sure you have the cable attached securely.

-Jessie

It is the old style. It doesn't seem to go in any further than I am putting it in. I reseated it a few times.

[BaltimoreGS]

Not trying to be condescending but since you just had the tach off I lean toward an installation error if it was working properly before.  Of course it could be a broken tach or broken cable.  Remove the cable and see if it is broken.  First try rotating it with your fingers with the engine off.  Then start the engine and see if it rotates smoothly (doesn't start and stop).

-Jessie

[meri]

Actually that was the first thing I did. I have no frame of reference, so it is hard to be sure, but the cable seems to work correctly. Increasing throttle makes it spin faster.

I even tried removing the tach from the cluster to test it on the cable alone. No luck.

[BaltimoreGS]

My bike is being disassembled at the moment if you want to use it's tach to test your cable. You ever in the Towson area?

-Jessie

[meri]

Not really, but if I can't figure out something that would be ideal. Thanks.

I was trying to find a way to disassemble the tach to see if there were any physical issues, but I can't see a way to open it. Not possible?

[tt_four]

The tach and speedo cables fit the same. If you think the tach might be broken, take the speedo cable out of the speedo and screw it into the tach, and take the tach cable out of the tach and screw it into the speedo, then go for a ride. Which one is acting weird? If the speedo is acting weird you'll know it's the cable, if it's still the tach, then you'll know it's actually the tach and not the cable. Does that make sense??

I know it works because when I put my bike back together this summer I actually crossed the cables, and after I started my bike I wondered why it was idling at 12mph.... haha

[meri]

Oh, that sounds good. I'll give that a try.

[DoD#i]

It can be a little tricky to get the hang of getting the squared off ends of the cables properly seated in the square socket as you thread the things together. If there are a lot of threads showing (particularly if there are a lot more threads showing than were when you took it apart - may not remember the tach, but you can pay attention on the speedo) the inner cable may need a bit of a wiggle so the whole thing can be snugged up with it properly fit in place. One of those things that's easier to see in person than to get from reading about it...

[BaltimoreGS]

The tach and speedo cables fit the same. If you think the tach might be broken, take the speedo cable out of the speedo and screw it into the tach, and take the tach cable out of the tach and screw it into the speedo, then go for a ride. Which one is acting weird? If the speedo is acting weird you'll know it's the cable, if it's still the tach, then you'll know it's actually the tach and not the cable. Does that make sense??

I know it works because when I put my bike back together this summer I actually crossed the cables, and after I started my bike I wondered why it was idling at 12mph.... haha

Excellent tip, I never thought of that   

-Jessie

[tussey]

The tach and speedo cables fit the same. If you think the tach might be broken, take the speedo cable out of the speedo and screw it into the tach, and take the tach cable out of the tach and screw it into the speedo, then go for a ride. Which one is acting weird? If the speedo is acting weird you'll know it's the cable, if it's still the tach, then you'll know it's actually the tach and not the cable. Does that make sense??

I know it works because when I put my bike back together this summer I actually crossed the cables, and after I started my bike I wondered why it was idling at 12mph.... haha

haha nice.

OP: If your tach cable is toast. I have a spare one for $10 shipped, if you're in the US. Mine sheared completely in half about a year ago. After enough wear and tear they just break in two.

[meri]

Looks like it isn't the tach after all. Same thing with the spedo on that cable. Taking in to account that the cable seems to spin fine.. I'm going to just take it apart, clean it and put it back together after I go find some lube for it.

Looking at the diagrams it looks pretty simple.

Anything specific I should look for while I'm going about this?