After backing off the choke when starting yesterday bike ran lumpy and found that no3 cylinder not firing

had limited time due to no workshop and getting dark so could only change the plugs. still no3 not kicking in

bike needed for work so had to ride it on the three remaining

got limited time so question is in what order best to check to try find problem

can switch 2 suppressor caps to see if problem transfers (not coil as no2 cylinder would go as well)

diaphragms next likely (how would I check them with carbs in place)

really don’t want the carbs off, unless last resort, to check for shite in float bowls as that will leave me bikeless if I cant get them back on again cos of the dark. Off Thursday & Friday so don’t mind tackling it then

anything else I could eliminate before carbs have to come off ??