NC23 bizarre running problem

[drifterwannab]

hello. all

having some trouble with my freinds bike and its got us all stumped

basically the bike is only running on cylinders 1 and 4, but if you disconnect the coil it will then start running on 2 and 3, plug the coil back in and it goes back to running on 1 and 4 again at idle or at revs. its also not charging the battery but this might be a sepaerate issue

we have so far

changed the coils 4 different ones in various combos,
2 sets of plug leads again in various combos
New plugs
3 different rectifiers
different carbs (but thefact it runs on all 4 but only in pairs shows its not fuel issue)
new battery
and the cdi off my bike which i know works fine

we are tottaly stumped

we have a feelng might have some thing to do with the speed restrictor in clocks? as that shuts off a coil doesnt it? maybe its stuck on or something?

[lloydiecbr]

try a new loom i would

[drifterwannab]

wel thats all thats left to change lol - but we dont want to be changing the loom

[leopard_pagan]

speed restriction symptom as follows:
bike will NOT rev past 5.500Rpm in any gear/neutral or as it gets to 5K rpm it runs on 2 cylinders.

if this is whats been happening.. its a simple fix. just by-pass the speed limiter with a resistor mod (DIY instructions or full plug n play mod kit available from me)
ebay Item number: 190317557067

[drifterwannab]

its only running on 2 from start up, doesnt change with revs -

[leopard_pagan]

k, which tells me its not the speed limiter.

"its also not charging the battery but this might be a separate issue"
> i think you need to investigate this.. its probably related and causing the problem

[vfrman]

Sounds like a short in the loom to me. Start by checking the grounds and work from there. You know it is somewhere in the ignition circuit from the symptoms.

[Waza4]

Try swaping over the pos and neg on the coils .

Are the coils well earthed to the frame same goes for reg rec battery and engine ect

[drifterwannab]

right some more developments.

checked every thing possible on the loom with the multi meter couldnt find any thing wrong other than the stator/generator isnt putting out a charge.

as we where running out of ideas we pulled the engine out and removed the head as we thought the HG might have gone between cylinders 2+3, but nope head, gasket, bores and pistons are all in good condition only thing was the in and ex valves we really sutty and coked up on 2+3

we are totally stumped !!!!!!!!!!!!

[lloydiecbr]

new loom