Is the Tacho known to be a bit erratic?

I have noticed that when mine gets to around 4000 it stats behaving erratically - swinging slighty up / down and does not go very smoothley upwards !

I have taken the inner out of the cable and oiled it, also removed the cable completley and the inner runs OK - there are no kinks or anything in the outer to cause the inner to snag.

Guess there is not much to go wrong at the engine end, so assuming it is probably the tacho itself - can the inside be lubricated without dismantling the unit?

Thanks.

Mine until I broke it (don't ask), was pretty rock solid. Deet has it again to fix my screw up, you might consider sending yours to him so he can go through it and make it as good as new.

You can verify if it is the tach and not something on the drive end by disconnecting the cable at the engine. Get a drill and put the cable into the Chuck and tighten. Run the drill in reverse and see how the tach needle behaves. I've checked a number of tachs and Speedos this way. My cordless drill has a high and low rpm range so when on high it will run the needles well up towards the max range.  If the tach operates smoothly then look at the cable or gears inside the engine case.  Look at the cable route too so no sharp bends.
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