hi all

bike is running on 3 cylinders, its on of the rears that isnt working,

any ideas ?

i have checked the spark and all is ok

swap a known working good plug to that cylinder. just becuase it sparks doe snot mean it is healthy enough to run.

plug was also changed,

leads also swapped at coil to check

Cleaned your carbs lately?

Always running on 3?

If the plugs are clean and dry does it miss just at idle and pick up with revs (slow jet issue)?

Sounds like you have already ruled out plugs though so next would be to investigate the carbs