if you mean the big MMB, that knob has left-handed thread, but forget it - nearly impossible to remove, and not worth it, either.
simplest and most accurate: get a bike thingy, perhaps from Sigma, one with illumination for a few $$, stick it where the worthless clock is/was.
There is a lot on the topic in the archives, both for the speedo and the tach which is much worse.
If you can afford it, get one of those all-in-one instruments from
Stack or
Motogadget. Looks much better, works as a first class instrument should and displays more info as well.
Much cheaper but of acceptable quality:
Acewell.
And then there are a number of digital speedos for motorcycles out there, very small and accurate.
bill