bouncing rpm-o-meter needle

[Anonymous]

Hey,

Recently, my rpm needle has started to bounce around while riding. It does it both while moving and sitting still. It bounces up and down, more than it should, but probably averages at about the correct rpms. Sometimes, while I'm accelerating, it'll bounce much more than other times, even though the acceleration and ride are smooth at a constant rpms or at a constant acceleration of rpms. Any thoughts on what would cause this? Just the device going bad?

Thanks,
--Tyler

[SqDancerLynn1]

Before condeming the tach I would clean and lube the cable/ check the cable ends also

[redliner1973]

Sounds about right, I would also check where it goes into the head, make sure it is all the way in and tight. :twisted:

[argonsagas]

Lube is probably your best bet, but on some bikes the inner tach cable has a drive nodule/olive/button/lump affixed to the engine end. This is the part that actually contacts the tach drive on the engine and makes the cable rotate. .

It can come loose and cause your symptoms as it spins around the cable, making intermittent contact.

A gentle squeeze with pliers can help. If not, (or if it gets lost) a new piece can be made, or an inner cable may be required.