Sticky tach?

[Hinermad]

The tachometer needle on my 750 doesn't seem to want to go higher than about 4300. I'm pretty sure the engine is turning faster than that, but I'll check with a clamp-on tach. (Actually I'd use a frequency counter and a pickup wire wrapped aroundf a spark plug wire. Does each plug fire twice per engine revolution?)

If the needle is indeed sticking, 1) is it a common problem? and 2) is there a fix for it other than replacing the tach?

 

[hannibal]

Each plug fires twice per revolution.

You can remove the cluster and then its backplate to get to the tach. Then carefully remove the face of the tach by prying up the metal lip. A tiny flathead worked well for me. I then cleaned the innards with PB Blaster to remove any crud. Finished by cleaning off with a can of compressed air and reassembled everything.

This helped but the problem returned. Finally spent money for a new tach cable and now all is well. It could be your tach is dirty or the cable is starting to break. The fact that it works at low revs suggests to me a dirty tach.

 

[Hinermad]

It could be your tach is dirty or the cable is starting to break. The fact that it works at low revs suggests to me a dirty tach.

Thanks. That's what I was thinking too, because when the needle gets to 4300 it just freezes like it's jammed against a stop. I'll try cleaning out the tach first, then if that doesn't help I'll get a new cable.

 

[hannibal]

My symptons were similar. At startup the tach would stay at zero. After a minute or two, it would begin showing the idle speed. It kept taking longer and longer to wake up until it stopped showing at reading at all.

It's pretty cool to see how the tach works too lol. There are some pics on here or one of the members' sites.

 

[BigD_83]

keep in mind that if the tach cable is spinning and the needle isn't moving, then something is getting stripped and the problem is only going to get worse

 

[Hinermad]

Understood, but in my case the needle is moving - just not above 4300.