3120xp timing adjustment

[Racer]

Hello guys. Today i making adjust timing on my 3120xp. Make w/o degree wheel (can’t have this tool) and take ~ 7-8 degrees. It,s ok for non ported cylinder or too much?
From improvements - muffler mod 3 port.

 

[huskihl]

File enough of the key so that the flywheel will rotate forward about 1/4” (6mm) further than stock