Strange NC24 issue - engine cutting out?

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So I've recently had the collector box swapped out on the NC24, and had the valve clearances done. I've also cleaned the carbs out and changed the air and oil filters, and oil on it.

Just the other day I took it down Stealth to get a new link pipe made up - and blimey, it looks great, really recommend them...

However when I went to pick it up, I totally forgot that I'd left the fuel tap to off (it's been a fair while since I've ridden it, and yeah, I am generally a tit), so we spent ages trying to start it, and bumping it. Got it to fire but died quickly due to no fuel, fair enough.

Eventually, after having basically flattened the battery, I turned round and pointed out how much of a tit I am, and it fired no sweat with the fuel tap on..

...However, couple of the chaps down at Stealth said it didn't sound right. Said it sounded like it was running on three cylinders.

I'm new to multi-cylinder bikes really so to be honest I'm not sure I know what the difference in sound would be like!

But they figured it could well be a fouled plug, and that it'd definitely get me home, obviously.

So off I went on my merry way... Little way over a mile (2.3km if memory serves!) and I'd just joined the M271 when the engine cuts out. The revs smoothly drop as if I'd just closed the throttle off, and I slam the left indicator on and roll to a stop in the hard shoulder.

The electrics are and were all fine..

However the bike would not start at all, ended up once again draining what little charge had been gained from the mile or so of riding, desparately trying.

Then followed the attempts to get hold of my breakdown recovery's number (New phone, sods law I didn't have the number stored!).


But it gets weirder!

Having charged the battery over night the bike now fires, and seems to run okayish, probably about the same as when we got it to fire at Stealth - so whether that's on three or not, I'm not sure! Any checks for this?

I'm a bit worried about riding it incase I have to call out the breakdown recovery or push it home, so I want to get to the bottom of this before I chance it!!

I'm thinking first step, check the plugs? But I can't help but think if it was to do with the ignition then all four cylinders wouldn't have cut out at once... or am I wrong there?

Anyway cheers in advance!
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GS125-> NT400->VFR400->CRM250->Z750 + GS125->NTV650 rat + VMX1200->GSF600 + GPz550

[MaybeGuy]

usually fuel starvation causes a misfiring cylinder. chuck some redex in the tank if you dont feel confident taking carbs apart (i would imagine they are a bastard on a V4).

could be a dodgey fuel filter too. is it on reserve?

have you run out of fuel?
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

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Carbs are clean, as I said, already had a crack at them before the valves and collector were done! Also they weren't too bad, considering.

aye it is, chucked it onto reserve last night as a last ditch on the hard shoulder kinda thing.

Plenty sloshing about! May be a tad off? Been in there maybe a month and a half, two maybe?
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GS125-> NT400->VFR400->CRM250->Z750 + GS125->NTV650 rat + VMX1200->GSF600 + GPz550

[ttr]

Oh, double post, but...

When the engine cut out yesterday, it really did not feel like running out of fuel.. I would have thought it would splutter and choke and die like it had a 50 a day habbit - when I ran out of fuel before, it did.

I dunno if a carb issue would feel the same, of course, but I would have thought so..?
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GS125-> NT400->VFR400->CRM250->Z750 + GS125->NTV650 rat + VMX1200->GSF600 + GPz550

[MaybeGuy]

may as well fill up just to be sure. most tanks on older bikes have a load of shit floating around at the bottom, sometimes blocking the reserve ''hole''.

i take it if you leave it for a while it starts up fine?
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!!
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith

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Double post again. Still fires fine. Seems to be running a fair bit better too. All four are firing (all of the headers are hot. Fuck me it's awkward getting at the back two!) and it's revving a lot smoother, where before there were occasional "hiccups" if you like.

Still doesn't explain the cutting out, though
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GS125-> NT400->VFR400->CRM250->Z750 + GS125->NTV650 rat + VMX1200->GSF600 + GPz550

[ttr]

Triple post, am on a roll!

Update...

In my hoping and praying that it's an electrical problem rather than having to tackle the carbs again, I perused the wiring diagram (admittedly for the NC30 - haynes doesn't have one for the 24?).. Seems that the only way the ignition circuitry could have failed in such a way as to kill all four cylinders, is for the ICU to fail, or for there to be a dodgy connection on the killswitch.

So I had a gander, seems the connections themselves are all good.

However after dismantling the killswitch's housing (and nearly losing the little ball bearing that holds it in the on or off positions..), seems as though the contact plates that break or complete the circuit were dirty as hell! Covered in grime (20 years worth I guess?! ) and some weird green looking goop. So I gave them a good clean.

Gets me to wondering, how likely is it that this is the cause?

Dodgy connection could have caused intermittant running I would have thought, but dirty contact plates? Possibility? Probability? Certainty?

Cheers


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GS125-> NT400->VFR400->CRM250->Z750 + GS125->NTV650 rat + VMX1200->GSF600 + GPz550

[Jenks]

my nc24 was renound for cutting out for stupid reasons.

The CDI Would come unplugged for no reason.. - but only slightly.

For some reason, it hated the rain....

Lets see a pic of it then I got a soft spot still !
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1978 MZ TS 250 1 Supa 5
1992 yamaha fzr1000 exup
1998 aprilia af1 sintesi

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Good fun! Did you ever find a solution?

Will take a pic or two after I've had her out this afternoon.
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GS125-> NT400->VFR400->CRM250->Z750 + GS125->NTV650 rat + VMX1200->GSF600 + GPz550

[Jenks]

well the CDI thingy, obviously just checked it then bound it in tape so it didnt move. no idea why that used to come undone, as i tryed yanking it and everything and it didnt move, i think it was pixies...

And the rain thing, no, i think it was just some crappy connector!
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1978 MZ TS 250 1 Supa 5
1992 yamaha fzr1000 exup
1998 aprilia af1 sintesi

[ttr]

Thankfully rain doesn't seem to kill mine. But it is remotely possible the fault is at the cdi.. Did binding it in tape see the end to such problems? I must admit I had a poke and it looks fine, but...
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GS125-> NT400->VFR400->CRM250->Z750 + GS125->NTV650 rat + VMX1200->GSF600 + GPz550