hey
i broke my head and i stiil dont know what is wrong
one plug is fine and the other is black and dry(left).
i clean my carbs chek the  electricity (except  the cdi and COIL  and coil wirings )
there are blue spark in bouth plugs . the bike starts fine and seems  run fine.
the carb dont  synchronizat yet (i wait to chenge the shims)
the main jet are 125 on both and air\fuel are 3 turns  out
it seems no problem with vacuum and fuel problem
no back fire
i wiil try to put non risistor plugs
is it the shims that cause the problem?
the bike is 97 uk
thank

You broke your head ? Could you explain in more detail what you have done, and what you intend to accomplish ?

to accomplish that both plugs will be fine
some dude try to adjustment the  valve but non success

I had a problem where one side ran lean and the other rich. turns out the float bowls were set too high on the rich side