hey guys i just fitted a brand new race exhaust, didnt touch any electrics or carb settings, went to start it (nc30) today and it was only running on 2 cylinders (when sitting on the bike the right ones)
so i took out the plugs gave them a clean and refitted and then it ran on 3 cylinders (front 2 and back right) the back left still not going so i took it out again gave a clean and still nothing i swapped the plugs over on the rear 2 cylinders and it seems as i wobble the spark plug lead to this cylinder (rear left) it fires then when i stop it doesnt, so i took the lead off and tried to bend the contact ring closed a bit more and it seemed to work a bit better and the header actually started to get some warmth but it getting late and the bikes really loud so i had to pack up before i could be happy with my work will have to wait till tommorro to try again and see if they all heat up form the first start up :) :)
anyone else had a problem like this and what did you do to resolve?
will keep you posted and what i find is the cause cheers, Tim

Well it sounds as though you've found the problem, but strange it would start happening after changing the exhaust.

Are you aware of how easily the plugs foul on nc's? I only mention that because it won't be the last time you have trouble with plugs if you ever flood it.

i hope im just about to start it now :) and we will see, n yer i think the fouled up plugs was a contribution as i did flood it a bit hehe lolz i will see if its fixed now :) cheers

Any throttle during starting can kill the plugs pretty quick. It gets expensive, they can't always be brought back to life!

Give it full choke and no throttle, turning the choke off once it's warm enough to idle.

yer they dont like throttle on start up ay! lolz
ah its wierd this problem got a strong spark at the plug, plugs clean and all that
but at idle (with choke OFF) the cylinder doesnt seem to fire (exhaust is still cold) but after a few twists of the throttle the exhaust is hot ? so do u think it might be the butterfly might not be open enough or blocked pilot jets??? any way of narrowing it down without adjusting the wrong thig hehe
cheers Tim

hey guys the rear left cylinder (#1 i think) is the one not firing at idle, but when on the throttle even slightly the exhaust header gets hot so i think it may either be the pilot jet is blocked or the air/pilot screw is incorrectly adjusted
any ideas on what to do to resolve problem?
cheers guys

Yeah mate could be that, or they need balancing.


I would strip the carbs down just for peace of mind on any bike I buy - you never know what you might find.

i just dont wanna do more damage then good, cause on the throttle it revs easily and no hiccups throughout the rev range, and me not being confident with these carbs i dont really want to go pocking and prodding and fuk something up even moreso???? lolz should be ok i just got to keep on the throttle lolz lucky its a race bike hehe

randallbass wrote:i just dont wanna do more damage then good, cause on the throttle it revs easily and no hiccups throughout the rev range, and me not being confident with these carbs i dont really want to go pocking and prodding and fuk something up even moreso???? lolz should be ok i just got to keep on the throttle lolz lucky its a race bike hehe

dude i was in your boots 12 months ago,my bike revved so fine and pulled through the range so well i didn't want to mess anything up,but i took the carbs offanyway,backed all the screws off counting the turns and wrote down what they were,then i had a base setting,now with a big help for this site i'm fixing problems that before hand i would have just rang up and booked the bike into get fixed

i'm no mechanic but i'm now happy to go tackle something knowing if i mess up i can ask on this site for help

Yeah, these bikes seem to be very easy albeit a bit time consuming to work on. A very big plus!