i had very similar intermittant symptoms on my nc30, and eventually the bike stopped running completely. i found the vacuum pipe on the fuel inlet was split. i replaced the pipe and she runs beatifully with no repeat of these symptoms so far.

Cammo & biobod,

These symptoms are the same as I had and it was down to a shitty vacuum pipe, if it were the carbs it would be all the time, the rubber on the vacuum hoses are shit and need replacing, as Cammo said pop Rick O an email to get you a new pipe, don't dismiss the rectifier fault though as there might be underlying problems.

I have had a sticky fuel tap internal before and that caused the same symptom you are having, the vacuum going into the fuel tap wasnt enough to unstick the diaphram and thus no fuel was getting to the carbs.. I would change the vacuum pipe and give the fuel tap a quick strip down and clean (very easy) and see what happens..

Glad you saved a bit of cash and now you know how to do the same jobs if ever required..

Hi guys, my friend is lending me his multimeter today so I can really check things out. I bought a reg/rec and new battery just in case because it is an old bike, I've just got it and no doubt things will need replacing sooner or later anyway. I've dropped Rick Oliver an email too for a vacuum hose. Thanks for the help, I'll let you know what happens. Shame its freezing!!

Man it is cold I even had some snow here in London..

Yeah, in London too. The double dip of winter really threw me off guard. I'm pretty sure it's the fuel tap vacuum hose, it even feels loose on the tap. I've got a new one on the way. Reg/rec was fine but changed the battery. Thanks a lot for your help guys, yet again.

What I would say is if you are now thinking to do the vacuum fuel tap bypass mod dont bother you will run into a few more issue's...

To me its winter until late April as I have known it to snow even that late in the year .... Summer aint far off though

ramonlv wrote: I bought a reg/rec and new battery just in case because it is an old bike, I've just got it and no doubt things will need replacing sooner or later anyway!!

your a wise fella lol... carry the new reg under the back seat so if you run into problems you got one you can swap 'on the road'

I've had a couple of problems like this before. I broke down in the MIDDLE of a really busy roundabout that linked a large town to another one, the local large airport, the local ferry port and the motorway to Glasgow.

Turns out my vacume hose had worn away and split, got a new one...then a wire came out from the plug going to the reg/rec. All sorted now and working like a charm (except my current issue with my dip beam ).
Even went a 2000km+ trip from Glasgow to Southampton and back in November afterwords...no problems what so ever. not bad seeing as i had never used a soldering gun before.

Cammo wrote:Also worth replacing the fuel vacuum hose. When it gets hot it can collapse in on itself restricting or cutting off fuel flow. Fairly common issue on nc30's. It's the hose that attaches to the small spigot on the fuel tap, and runs to the r/h rear cylinder under the carbs.

Rick Oliver sells some thicker walled tubing that won't do this.

This is my bet