TOPIC:

gmorning i have a big problem my z550 i try to set the carburation but the spark is always white and sometime the first cylinder don t start propertly and anything change when i move the mixture screw and in one minute the motorcycle come really hot anyone can help me ...

i have check coil is ok cable and spark plug with new spark

sometime the first cylinder don t start properly (intermittent firing).
Replace the spark plug wires. or redo the spark plug wire connections. if your coils have the ribbed compression boots, unscrew those to remove the spark plug wires. if the wire is oxidized, cut off the ends a few mm.

Ignition coils. the coils can test good cold, but fail when they get hot from riding the motorcycle.
A simple test. ride the motorcycle at high speed, then stop & touch the coils. press hard with your fingers.
they should be warm, not hot. practice touching the coils when the engine is cold. don't get burned by the valve cover.