Hi all been given an old gsxr400 gk71f ,so i'm back in the saddle after 23yrs,bike runs well one day s##t the next.think it a prob with the coils. pots 1 & 4 not working all the time but when they do its a joy .look forward to hearing from anyone with help & advice.can't wait to take it on a decent run.
mike

Hi Mike,
Sorry not to have posted but been busy. If 1 and 4 are not fireing it could a bad coil (wasted spark so fires both plugs), probably loose connection of the low tension wires or bad wires from the cgi to ths coil.

got myself a meter to check ohms but need specs also not sure how to do it ,probably check input on low tension side on both coils & see if same

i think i have got the same problem with my gk76a, i dont know if they are the same or not but where could you buy a new coil from