NC24 and coil sticks

[Neosophist]

I think your confused.

Magg is right.

The CBR600RR coils are 12v coils that are fired indivually, if you read moriwaki mans guide on zxrworld when he fitted stick coils you will see he used the proper Honda loom too, which you have to chop up and rewire in series.

A downside to wiring them in series is you half the voltage.. the same as if you fit another resistor to the coils for the NC24.

On the NC24 you wont run into the duty cycle issue.. a few people have had issues with stick coils failing, mainly on high RPM track bikes... if your firing the coil twice as often (as with wasted spark) you risk melting it.

I had a ZXR400 and had denso stick coils on it and took them off.

The NC24 coils are quoted as being between 2-4 ohms reisstance. Stick coils are around 1.6

I wouldnt risk frying the ignition box by connecting them straight up, nor would i run them at 6volts.

And yes you can replace the plug leads and get new caps if you want to.

Not sure how much power the coils draw off hand but you might end up needing a big chunky resistor.

Also never had an issue on either ZXR or VFR with coils being in the way, esp on the NC24 there tucked away in the middle of nowhere for the rear and the front are on a bracket that pops off with a couple of bolts should you need to remove carbs.

[Neosophist]

Just did a bit of calculation (may be wrong.. have drank beers)

Using Ohms law (V=IR)

12v 2-4 ohms gives a theoretical max current draw of between 3 - 6 amps per coil. (72 watts)

http://uk.farnell.com/jsp/displayProduc ... {placement}

Heres a 2ohm 100watt resistor that should handle the power of the coil, but there 15 quid each, and youll need 4.

[Morespeedvicar]

Your right dude, you could i suppose run a resistor on the +12v line which is common to all the coils (cos usually to 0v is switched) but like you said it'd have to be a high wattage and get really hot aswell. I can see why it looks like a good idea, having 12v wires running around a bike is easier than big ht wires but chaging resisances on 25 year old electronics isn't worth the grief.
cheers
Ian

[magg]

Advectus, here is more on the subject:

viewtopic.php?f=24&t=39699&start=10

[CyberFox]

Hi ! I`m from Odessa, it`s a city located in Ukraine

I apologize that I raise the old topic

I had a problem with a ignition coils on my bike as well.

The 1-st cylinder did not work properly. Idle run was not stable, engine always tried to stall Also engine did not give a full power, there was a huge failure in acceleration dynamics about 6000-7000 rpm. I had such a feeling that it was the early ignition or the problem with the inlet valves, because the ignition flash was going into the carburetor. I checked everything... Carbs(cleaning and balancing), air leaks, spark plugs, valves gapping, CDI, ignition timing... But with no success Until I figured out that the problem was in the ignition coil of the first cylinder !

The new coil is а big problem in my country, and delivering the needed parts from UK or Japan is too expensive, and I begun searching for alternative solutions. As four individual coils are fitted on my VFR 400 NC21 (instead of two twin-coils fitted at NC30), I decided to try a COPs (Coils on Plugs). After long searching in Internet I found a guide on installing COPs to Yamaha V-Max at the web site of its owners.

After thinking a bit over the guide I consulted with my old friend-mechanic who gave me two COPs from the Kawasaki ZX6 (mitsubishi #F6T560). At the same day I installed them on my bike. All problems were resolved ! Idle became stable 1500 rpm and engine gave a perfect acceleration dynamics in all rpm range !!!

So... That`s my story I would be happy if my experience stand somebody in good stead Because the NC21 and NC24 are pretty close by their construction...

[Neosophist]

There are a few problems with stick coils.

Most people think they are "better" but they are often weaker than old fashioned coils, which provided more sparking power than stick coils which was needed due to carburetion being not perfect, modern FI bikes have a great mixture so they dont need sucha huge spark to get the mixture going.

Look at racing coils like dynacoils, they are huge.

the most serious problem is the ignition box expects coils to be in a certain range of resistance.

the nc21/24 coils have 2x the resistance of most stick coils, so by changing the resistance you are increaseing the current flowing across

i.e lets assume 12v 2.4 ohms, using ohms law this is about 5 amps of current.

if you wire up some 1.6 ohm stick coils you get 7.5 amps of current, this is a 50% increase.

while it wont instantly kill your ignition box, it will melt it overtime, ive seen people try do it on vfr750s and other bikes without using anykind of ballast resistor and eventually the igntiion boxes give up.

you can use pretty much ANY 12v normal coil as long as the resitstance is in the same range, it doesnt have to be an nc21/n24 part.