My Tach Responds Slow

[Milan]

Have a tach on an RD400.
When I rev up the engine, it is slow to register the RPM's.
When I shut the bike of, its a second or two, till it zero's out.

Put the tack on the RD250, works fine.

Took the cable out & in good shape.
Looks like a more than usual bend on it tho close to the case, in the metal part.

Took the gear out, it also looks fine.

Would too much bend in the cable, cause the inner cable to go " Spring Like " & twist & Untwist?

Or could the mating gear in the engine be slipping somehow.
I have never yet had the pleasure of taking apart cases.

M