Hi there
Quick 1 for ya
Ive just done the valve clearances on my friends nc30 as he was finding it hard to start unless he pushed it with the start button. the clearances had never been done! there was no clearance at all on the front 2 cylinders. Also fitted a new clutch while i was at it.
We went to start it after an it still wouldnt fire. Unless you pushed it an then it sat an run fine an took it out on a 40 mile ride. runs fine other then a flat spot between 5-8rpm then it kicked an flew. stopped the bike an it wouldnt start. took 1 of the plugs out an hit the starter an it wouldnt fire for a few seconds then it would spark but very week. Ive tried fitting another CDI an coil packs but still no good. cleaned up the contacts on the coil packs but still no good.
Has any 1 else any ideas as to what could be up with it as he needs to get it sold as hes leaving the country in a few eeks an need to get it sold!
Thanks for any help!
Cheers steve

It's usually poorly spark plugs. Sounds like incorrect carb settings are possibly fouling them, this is common - the small plugs are fragile (and expensive).

If you can get hold of just one new plug try it out and see if the spark is stronger.

The plugs init have prob only done 200 miles as it had a service a few months back
i tried the plugs i took out of it in there about 30mins ago an just held it against the frame an still no joy. it sparked twice b4 it run the battery flat

Have you checked the battery voltage while the engine is cranking, also what battery voltage do you get with the engine running. Poor charging and weak battery will give slow cranking and weak spark making it hard to start.

I havent checked the battery but it charges fine once running an takes about 20 mins of cranking b4 it starts to struggle turning it over. Earlier it started fine 3 times then went to try again for thr 4th time an nothin. It just didnt want to know

+1 check battery, and charging system will cause weak spark. Over rich mixture fouls the plugs. But big NO NO with these bike is starting and not getting to full operating temp. This will also kill a new set of plugs in no time

its still running stock fueling. its an import with stock pipe! the bikes never been modded in anyway. totally original. will check rectifier an stuff later

The bike should still start even with a stuffed (or unplugged) rectifier.

Plugs... it always is.

Even if the plugs appear to be sparking outside of the engine, it doesn't mean that they'll be sparking properly (or at all) under pressure inside the engine.

Take all 4 plugs out and check them. Clean them as best you can and heat them for half a minute over a gas hob - this usually revives them but they can't always be brought back to life. Leave them out of the bike overnight so any fuel in the cylinders can evaporate.

Reinstall the plugs and crank the bike over using FULL choke, NO throttle. Even just opening the throttle when starting the bike can foul them.

This is a common problem, these bikes are very susceptible to flooding and the small plugs die easily. See how you go.