Grab a big box of cotton tips.
Bottle of turps
Bottle of metho ( no drinking it)
small bottle of light oil(sewing mach stuff is good.
Small artist paint brushes.
Hobby fluro orange paint for the needle tip.
Clean up the face with the turps and no hard rubbing Usually the tuprs will be good enough to do the job, Metho will do it though much more care is needed to not dissolve the face print.
The mech again can be cleaned carefully with turps or meth and any pivit point just a minute drop of oil.
https://www.oldjapanesebikes.com/GT750J_Gauge/page-3Hard part is getting the clock apart. 70,s Suzuki used two methods, a green glue or a melt. a small knife blade flat screw driver can be used to break away the over lapped plastic. Tarzans grip is good for resealing.
There is a website that explains how to do GT750 clocks. If i can recall the URL I will pop it in here.