Honda cbr 400 nc23, Weird problem with cylinders

[kermity2k2]

hello. all

having some trouble with my 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?

[Bikeless]

The speed restrictor in the clocks is a small piece of metal that passes through a sensor when the bike reaches 112 mph,so check the speedo needle isn't stuck round in this position or there may be something rattling around in the speedo blocking the sensor.Of course it may not be the speedo sensor at all.

[the grim reaper]

[kermity2k2]

thanks for this,

i will give it a go tonight

[Blue_SV650S]

You can disconnect the speedo sensor wiring and try again with the bike in neutral just in case it is that (but I doubt it, can't see why it'd switch from one to the other just coz you disconnected one ).

Please note:- I'm not 100% sure with the CBR, but on the NC30, the speedo sensor returns a signal to the CDI and only upsets it when it is in gear ... so neutral should be fine. You can take the sensor off totally and run it in gear if you put a resistor in there to fool the CDI the sensor is there (which I suggest is what you do if it DOES turn out faulty! ).
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The purpose of life is to fight maturity.

[finpos]

Did it just start doing this on it's own, or did something else happen?

f.

[Bikeless]

[Blue_SV650S]

[Bikeless]

[kermity2k2]

We have played about wire the restrictor and by passed it but the problem was still there.

We have played about with the loom but no problems found. So took the engine out to have alook at gasket but couldnt see any problems.

Real puzzler this one. Thinking it must definatly be electrical, As we have had it on all 4 cyclinders for a bit last week.

Unknown of previous problems as bike was won on ebay, guy said he had changed alot on it, but lied.

Keep the idea's coming please, we will soon nail it.

[drew70]

Try replacing ignition pic-ups there is two on the 23 one for each coil. They are behind left hand engine case.

What colour label is on your cdi, blue or gold ??

[finpos]

The only thing I can think of is that the earth for the whole coil pack is poor so that each coil is earthing itself through the other one instead of to the frame. Might happen if the bike frame has been painted or if an earthing strap has been lost.

f.

[prawny1]

Try disconnecting the fuel pump relay then wire the fuel pump to run off the direct ignition feed i.e. fuel pump on when ignition switch on(the relay plug should have the wires you need, just seperate them and bypass its pretty straight forward)

The standard set up uses the cdi to activate the fuel pump and gets a signal from both sides of the cdi (coil 1 and 2), If the relay is shorted inside you will get mixed signals to the coils (or 30v at the pump like i did).

Unless you know the systems are connected the fuel pump side of things gets over looked when testing ignitions.

[kermity2k2]

Hi the CDI is blue.

I have not tryed fuel pump idea yet, as we still have engine out, just going to give it a quick clean up and maybe change Gasket. The will try the ideas suggestion.

Thanks again

[Drifterwannab]

Hi

Iam helping Kermit fix up this NC23 as i have one myself.

We have earthed the colis direct with a separate earth lead and it didnt make a difference, we have also checked voltages on the fuel pump and thats fine too. we tested the ignition pickups and they where fine aswell.

However when we went to de restrict the clocks, it doesnt have the restrictor unit. As it had a blue cdi fitted i presumed it was a RRk but going off the frame number its a RRJ - so having the blue cdi fitted to the RRJ instead of the gold label, would that cause the running issue

[mbarbee]

Heyy, were about is the wire to cut to take the bike to top speed not 112mph, ive got a honda cbr 400 nc23, i cant get mine to start aswell done almost everything. cheers.
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M Barbee

[preece59]

hi sorry to but in but can anyone help me please i got a honda cbr400rr bike it was all running perfect in the bike and i have put engine into a quad bike and since putting it into quad bike it wont run properly the only things i have changed is 1 and 4 on exhaust and 2 and 3 are set up as 1 and 2 together now and 3 and 4 together going into one back box will that effect anything ? also i havent fitted airbox as it dont fit wiv tank on but tryed it wiv air box and still runs the same thats all i have changed.....wen i rev it up in gear and nuteral u carnt just pull the throttle back how u want u have to do it really slowly ova wise just goes burrrrrrr and no power is there ???? wen i rev it all the way quickly i notice the sliders inside the carbs on top move half way then struggle to go to the top slowly but wen there at top bike revs perfect why is that please? i have cleaned all carb out the sliders move freely please can any body help me with this as im dying to get on the quad bike properly ......check all sprak plus put new ones in all spark all time perfect and petrol pump works perfect thanks people for reading