tachometer jumping + whirring noises

[AnonRider]

So, I went ahead and tried out my new heated grips and I found that the bike was running beautifully.

but after it hits 5k rpm a whirring sound comes from the engine and the tachometer starts dancing all over the place. the problem fixes itself after going through the gears and keeping under 5k rpm.... but, what the hell is the problem here?

[gsJack]

Lube the tach cable first.

[AnonRider]

Lube the tach cable first.

will do, thanks man- how have you been?