OK, I ran across this mod on another forum for my fireblade.

Here is my question...has anyone seen or heard of this mod on the NC30? I think coil over plug is an excellent idea to replace the coils on the bike...

our man Neo will come and tell you about it..It has been discussed on here before using a cbr6rr subloom and gubbins.

I am sure that Lasse did it too on his race bike

vfrman wrote:OK, I ran across this mod on another forum for my fireblade.

Here is my question...has anyone seen or heard of this mod on the NC30? I think coil over plug is an excellent idea to replace the coils on the bike...

We had this discussion up recently.

Normal stick coils (COP) are around 1.6 ohms each, where as the NC30 coil packs are around 3.2 ohms.

Since they are wasted spark and two plugs fire at the same time you can wire the stick coils together in a chain to fire at the same time like the original coils do, and more importantly the resistance is about the same.

If the resistance is too low you will burn out the ignition box.

You can do it on any 'wasted' spark engine easily, i.e. most I4's. ZXR400 etc.

I've run them on a ZXR400 but never a 30 as the plugs are tiny, not sure if you would need adapters to fit the plugs.

Anyhow there are some drawbacks to this.

A modern COP bike will fire each plug when it needs to, sending 12 volts to the coil.

By wiring the coils up in a chain you divide the voltage, so only 6v to each coil.

The next issue is duty cycle. The COP stick coils are designed to be fired when needed, not wasted spark. By converting them to run as wasted spark you are firing them twice as often as they were intended to be, this has caused cases of coil failure, presumably due to overheating of the coils, this issue has mainly been seen on track bikes.

On the ZXR it was convenient to do this as I wanted to put in a ram air box and the coils on the ZXR are mounted right where the airbox would go.

I didn't go that way but ended up taking them off and sold them on. I have some dyno's with and without the stick coils and there was no perfomance increase or any difference with starting.

People have reported a better start / better running but I think it depends on how good your original coils / plug leads are.

If you have an issue, a new coil (either stick type or tradiaional pack) will fix that.

For the cost and effort, unless there is a specific issue then I havent come across any benefit, only a list of things that have gone wrong and don't like riding about with the thought that the coils might someday die, especially on an NC30 as they get really hot.

Dropping the volts to 6v per coil will still give a good spark, but not as intense as a 12v would if it were on the bike intended.

Hope that helps, if you need anything more post up.

Thanks Neo...crossing this one off my list then. LOL.

vfrman wrote:Thanks Neo...crossing this one off my list then. LOL.

If you had the bits knocking around then I would say try it and see, but if you need to go about buying stuff to do it then I really dont recommend bothering with it.

I don't have the parts, and I was going to do this on the fireblade, but now I am thinking it isn't a great idea.

I'm still toying with the idea of using a car coil pack (like off a mondeo or summats) if i can find one with the right ish resistance. Mainly cos my front ht leads are a bit ropey and it'd be something to play with. So when and if i do have a go i'll post up with any good or bad points.
Cheers
Ian

vfrman wrote:I don't have the parts, and I was going to do this on the fireblade, but now I am thinking it isn't a great idea.

Why not? I've done this mod on IL4s many times with no issues at all. However, if your 'Blade is an injection model, it may be worth altering the ignition timing a little.

Apparently with the coils wired in series the lost voltage means that the coils will take twice as much time to ramp up to required output. I haven't seen anything definate yet but, the coils dwell time is 1.5ms to 2.5ms. So at 6 volts they need 3ms and 5ms respectively. Also there is a 1ms for discharge too. So at higher rpm there may be issues.

Here is some speculation I found while looking for a definitive answer to why some people get problems, its only conjecture but perhaps due to the above would tie in with it being mostly race bike users reporting problems.

As I mentioned before though, this `mod` doesnt offer any performance over working conditino standard coils, so unless you have problems or loads of spare cash then id spend it on something else.

That is why not.