NC30 Carb rebuild (Random results + coolant leaks)

[st22041967]

Hi Guys n Gals.

I'm an avid reader but this will be my 1st post so PLEASE be gentile with me.
So I’ve had my NC30 from pretty much new. I’ve ben moving around a bit so the bike never got used but was dutifully changed and started every few months and moved from house to house. Sometimes I even took it out on the road.

Anyhoooo’s last time I went to move the little darling it just wouldn’t start. I’m not much of a mechanic but I recon it would be fun to sort the issues myself. After a short amount of time I’ve figured it needed a new battery and the Sh1t cleaned out of the peta-cock and filter (Petrol tap?).

“Excellent” says I; now it has a nice steady supply of fresh fuel, and nice strong spark and she’ll start like a charm……………… No such luck. Next step is the carbs which have never been cleaned since new so I dutifully buy a ultrasonic bath and strip the whole lot down as per the sticky “NC30 carby jetting - DIY guide” by Cammo –Lifesaver!!!

All back in one piece, the main carb screws are screwed out 2 turns (Standard jets and exhaust BTW) from closed and the carbs are bench synchronised to all open at the same time which even if I say so myself looks pretty spot on (I even put a lamp through the bell-mouths to see if they were all spot on).

Just for good luck I got some new carb mounts as they were being a bitch to get back on. I prime the carbs from a separate fuel supply made from a bit of hose and an old washing up bottle to gravity feed nice new fuel( All cleaned and dried of course) . I pull the choke, press the starter and OMG it starts within about 2 seconds. I have never been so proud (or surprised) of a job in all life!

Now for the problem, It just won’t start again (Mostly). I have since had the carbs off about 4 times and again it either starts absolutely 1st time or no amount of cranking will ever start it and I have to take the carbs off empty it out , reload and start again.

I'm fresh out of ideas.

Anybody……………….?

Thanks in advance.

Stu

[bikemonkey]

Spark plugs.

[st22041967]

I like your thinking........ Nope. New plugs costing about £45.00 already installed

They still look clean and generally good.

Thanks for the quick reply though, much appreciated.

[bikemonkey]

Hmm, coils?

[st22041967]

Once again I like the thinking but spark is strong, plugs new and when it fires up it sings like a bird ..... A breath of inspiration please , I'm staring to think I have no idea of how the squirt, squeeze, bang, blow theory works on these demons [emoji3]
I may need some voodoo magic or something

[bikemonkey]

Voodoo magic may be needed indeed!

Hmm, so the bike intermittently starts but always cranks?

Have you made sure the fuel tap went back together properly? And is your vacuum line intact?

Plus when was the last time the valve clearances were done?

I'm clutching at straws here like yourself! Maybe another brain may help...

[st22041967]

I thought the fuel/vacuum as well which is why I'm feeding the beast via a gravity supply......... Like I said when I refit the carbs it starts 1st time and runs sweet. Then any subsequent attempt just gives me jack......
Help me obi whan your my only hope

[st22041967]

Ps never done the valves but previously it always ran quite sweet which is backed up by it sweet sounds when I do get it going

[bikemonkey]

Possibly a/the float valves could be sticking, allowing the carbs to flood the cylinders?

[richyrd5]

Float valves or vacuum tap pipe..but I d go for float valves