running on 3 cylinders unless spark plug changed

Yes you're right ! Sorry i wrote it wrong ! Thanks for correcting me 1

small update, i have changed the other coil as well and so far so good.
The bike runs pretty good, now the only thing i notice is a little hard time for it to get gas sometimes when switching gear.

M

If not already done, and especially if the non-combustion issue persists in #4 cylinder (runs okay with brand new spark plug, but soon starts missing), would suggest performing the clear tube test on #4 carb to assure that the fuel level is within specs and particularly that the fuel level isn't too high. Because a too high fuel level can result in an over-rich mixture even when the carb is otherwise perfect.

Good Fortune!

HI Patton, i have to read more abotu that test. seems important to do indeed. it could just be too rich.

M