21mm carb issue?

Alright everyone, got another bike Gilera ice! Running perfectly, bought a polini 21mm carb put it on got it set up on a 82 running for a day but it stutterd on pull off turned out it was my spark plug only half way in(A) but no pulled it out this morning and it won't start? I have spark and compression? And when I take my plug out its black and oily? Any help but be a massive help!

 

if its black and oily it means your engine is running too rich or you got to much oil in you mixture

 

And too stop it running rich what do I do? Cheers edgar!

 

Smaller Jet, Or Thin The Oil Mixture Down

 

have a read of the carb section on here bud it explains what to do iirc you turn the mixture in half a turn until it runs spot on but be carfullas you may lean it out to far and have no oil going there