Leave it till you"ve tried it, if its rich it will 4stroke [, kinda splutter] at a steady throttle, the biggest damage that can occur when jetting is at W,O.T. on long staights, or hills,
What about it running better with choke removed, it should bog right away , unless stone cold,,?
Unless its pulling air down from top ,then no vacume to draw fuel up thru choke passage,
this would make it rev cleaner,
Lets go back upto pcture of your carb,
The choke feedpipe is too short, to dip into the well ,[incarb bottom] so I think it aint drawing fuel WITH the choke removed, it be drawing air ,,
your thought s Paul
Run the cursor up to the browse box [top left] left click on it - it will turn blue - then right click - drop down box appears- click copy
then click on your post on here, - right click - drop box -select paste.
Do this with both sites open on different windows
I usually take out the jets to see what type they are, then go on ebay ,search mikuni jets, [ size] and compare the types,
Good the plug is standard,,,