NC35 cutting out

[arsey30]

1 cylinder down will not give much of a problem
Tick over will be slower but reliable, revs may drop back slowly and pick up will not be crisp.

2 cylinders out will reduce engine power considerably, do check that all 4 are firing.
Warm engine until it ticks over off choke.
Leave to stand for a while until ex pipes cool but engine will still be warm
Run engine off choke and check ex temp in 10 to 15 secs to see if all the same.

Fuel flow rate should be full bore, not a fast trickle.

[speedy231278]

I don't suppose anyone has every been bored enough to measure the actual flow rate? lol

New plugs ordered, I''m pretty sure they are up for replacement anyway. Ironically I didn't get any a few weeks ago when I could have got triple Nectar points on eBay because I figured the miles were so low on the current ones that the time interval could be ignored. Perhaps this has forced my hand! Also ordered a remote fuel can as it will hopefully help diagnose any flow rate issues, and be handy for when I balance the carbs which are overdue for that. Other new toys is a laser thermometer. Excuse is that I can use it to measure the temps on my reptiles and fish as well....

[Morespeedvicar]

Shame your getting soooo much grief!!!
I'd be taking the carbs off and cleaning them out, and check the vac pipe has no crack in it. I'm guessing nc35 have the plug in the right hand side of the v like 30's do, so maybe check that aswell.
Other more drastic steps for testing are make some test leads up, like battery to coils and stuff like that to eliminate a dodgey loom, or even a replacement cdi (ok I know it's not but heyho) or try and borrow one.
Were are you located?
Good luck.
Ian

[NGneer]

Speedy, A fresh set of plugs and a good check of the carbs seating/hoses etc is always a good place to start, and your bike will thank you for it regardless. Fingers crossed this solves it for you, but this (IMHO) doesn't answer the question of your poor charging readings.

Having had mine laid up over the winter (no optimate), the battery was totaly flat when I went to fire it up. I managed to bump it with the theory that I would take it for a good spin and get some charge back in the battery. It transpired the battery was totaly knackered and though I could get the bike to drive, I had to gently coax it up the revs so as it spun up a little faster it in turn provided enough 'electrickery' to power the more rapid spark demand required. If it tried to 'blip' it, it just stuttered and died. In effect it was only just self sustaining, ran pretty lumpy and even when riding along at a steady pace turning the lights on was like hitting the kill switch - as the system just could not cope with the added demand.

A new battery solved my problem and I know you have got a new battery fitted, and a new Rick O Mosfet reg/rec so in my limited electrical fault diagnosis skills there must still be a problem within your charging circuit. Have you actually checked the generator / generator cables to make sure nothing is burned out / melted / breaking down?

I am no Electrical wizzard like some on here (guys - please jump in here) - but my logic says that this could potentialy give you your poor/intermitent charging readings which would then be made worse when you put the system under extra load IE either putting the lights on or by reving the engine.

While you are waiting for your new plugs to arrive why not get the multimeter out and do an end to end check of the charging system.

[speedy231278]

I haven't actually put the new battery on yet. I didn't want to risk damaging it by flattening it if there were still charging circuit issues. I've asked Rick about the different sized stator, so when I get around to opening my email I'll see if he's replied. In any case, as I'm getting 14.5V with the OE lamps, right now I think it's the least of my issues. The wires on the new stator and reg/rec were both sufficiently long that I was able to connect the two together directly, and bypass the stock loom. The wires in it for the charging circuit are very ropey, which is why I've eliminated them from the equation. I had already bypassed the stock loom for the output, and it gained me at least half a volt. All wires are crimped and soldered for the best performance. Unless the battery is doing something really odd, I don't see why changing it would make a difference, although I do have that option if I want. The current one was charged a week ago last Sunday, and left until Friday just gone to settle, so it had five days to show any signs of abnormal discharge. It had 12.82V on it when I got back home, which normally indicates it is not unhappy.

Anyway, I can't tinker until I get home on Friday. I'm 90 miles from the bike right now and just sat here all frustrated that I don't have the luxury of a week's worth of evenings to investigate.

[arsey30]

With a fully charged battery you do not even need a generator to run the engine.
Race bikes run total loss ignition without a generator, and will last out a track day.
I still suspect all 4 cylinders are not working

[Neosophist]

arsey30 makes a good point.

If your worried about the electrics diconnect the genny feed plug to the reg/rec and you wont charge the battery but a fully charged battery will run the bike plenty long enough to test this theory.

Are all your downpipes getting hot will tell you if all cyinders are working.. if not then you need to see if your getting fuel / spark / air (plugs / lead easy to check), coilpack should be ok if other cylinder is firing as they run in pairs.

compression / valve clearnaces are other issue for this problem.

To me it sounds like vaccum hose.

My NC24 cut out on a big run aroud 10000pm it just stopped... after a bit of time it started up fine and rode about 300 meters before dropping out again.. replaced the vaccum hose and fine since.

The only other thing I can think that would cut it out dead is short somewhere that interrupts the spark to all plugs.

[speedy231278]

I presume when talking about the vacuum hose, you are thinking the fuel tap diaphragm is closing? The tap on my bike has the vacuum system bypassed, the vac feed goes directly to the Scottoiler I have fitted on it. If, in the unlikely event is has come adrift, could that cause an almost total loss of power?

Rick has confirmed that unfortunately I've ended up with the wrong stator, so that will hopefully sort out the low output from the charging system with the Nightbreakers, but I can't see it being the running issue, since to begin with the bike was running absolutely perfectly until it died.

Right now I'm thinking either the plugs are grotty from all the unsuccessful starting attempts, the carbs have somehow got miffed from the same thing, or there's still an issue with the connector on the kill switch that is preventing the coils from drawing the necessary power .

Surely, it MUST be something that has occurred between the initial failure of the bike, and me putting it back together after my attempts to fix the issue on Sunday?

[speedy231278]

A random thought has entered my head. Seeing as I had all the connectors under the tank apart, if the whole bundle of those and their big rubber sheath are lying too close to the airbox snorkel after I've put them back together, could the engine just be suffocating? The big rubber flap that goes from the rad to the intakes is present and correct, so there's not a huge amount of space in there once everything is in place....

[speedy231278]

All sorted. Was the plugs. Just very odd to me that they'd actually produce a spark, yet the bike had no oomph. 40 trouble free miles yesterday, so hopefully all issues sorted. Save for the fact one of the plug leads had the outer sheath split the whole way around while I was changing the plugs. That'll be something to change very soon, have a feeling that it would leak the spark if it rained!