So who wants to know about the green Mikes Coils?

[clcorbin]

They look like Dynas, but the Dynas only put out 30k volts. The green monsters put out 45k volts with 12.5v input, and 75k volts with 14v input. Lots hotter than the Dynas.

Keep in mind the physics here guys. You can put 1 MILLION volt coils on there, but you will ONLY have what ever voltage is required to ionize the spark gap.

Basically, as the coil is fired (by opening the power ground on the primary side of the coil), the voltage across the secondary side of the coil starts to increase (rapidly!). Eventually, one of two things will happen: The spark gap on the spark plug will ionize and the plug will "fire", or the magnetic field in the coil will collapse. The first one fires the cylinder, the second one causes a miss.

Once the spark gap has ionized, the voltage across that gap drops VERY fast. It is this point that the amount of energy stored in the coil's secondary winding is dumped into the spark gap, hopefully lighting the fire properly.

In truth, we want high ENERGY coils with low resistance so the coil can dump as much energy into the spark gap as quickly as possible. Many aftermarket coils use many more turns of wire on the secondary side to get the voltage up. Because of physical constraints, they use THINNER wire so they can pack the extra turns in there. This leaves us with a problem as more turns of thinner wire = higher resistance. Higher resistance means it takes longer to pump that energy into the spark plug, which means we have a weaker spark.

Usually, you are only going to need high voltage coils when you are trying to light a difficult fire. For example: Running very rich. Running very lean. Running under boost conditions. Running very wide spark gap. etc.

Thankfully, it looks like these coils are physically larger than stock which means they could wind on more wire that is the same, or even larger, diameter than stock. That would be good.

[dbeardslee]

In terms of resistance specifications, they're basically the same as the stockers - 3ohms primary and 15k ohms secondary. They are considerably 'fatter' than the stock coils. Not sure about all the physics, but what I am sure of is that they make a huge difference in the way the bike runs.

[XSokieSPECIAL]

When you install these Green Monsters shouldn't the plug gap be wider?

[dbeardslee]

I had hot coils on it before (mikes black coils), so I've had my plugs gapped at .035" for some time. When I installed the iridiums they already come gapped to .035", so I didn't have to mess with them. Good thing too, as NGK tells you not to mess with the gap on iridiums due to the brittle nature of the electrode. According to mikes xs info, they have tested the green coils with gaps up to .040", so anywhere between .035 and .040 should be good. That being the case, with the wider gap the 'air' resistance should be more with the green ones requiring more voltage to jump the gap. Again, I'm not sure how all the electrical physics works - I just know they work.

[clcorbin]

That being the case, with the wider gap the 'air' resistance should be more with the green ones requiring more voltage to jump the gap. Again, I'm not sure how all the electrical physics works - I just know they work.

Correct. The larger the spark gap, the higher the secondary voltage has to get before it ionizes the gap and fires the plug.

[CA]

So I followed this blindly...

It felt very weird drilling into something I just took out of the box new. The drilling wasn't too pretty but it got the job done. I hope these things can take a drop or two on the floor. Guess we will find out tomorrow. Here is a cell phone picture of my handiwork



A few questions. I got the black 7mm plug wires from Mikes and am a little confused how they hook into the coils. Does half of the connector go on the rubber of the wire and the other go around the bare wire then plug into the coil. My real problem is do I crip down on the bare wire so there is a good connection, OR do I leave it uncrimped (barely touching it then) so it fits securely into the coil. Also is it cool in I use my old plug ends? Do they just screw into the wire?

Does it matter which wire I put to the 2 and 3 cylinder from the one coil and vice versa?

Sorry this is my first time doing ignition anything.

Also what about the ballast resistor?

Thanks beardslee for the write up.

[MindWebs]

yes it matters witch coil wires go where... to a point..

coil #1 feeds spark to cylinders 1 and 3
Coil #2 feeds spark to cylinders 2 and 4

as to which coil is which.....

i'm not sure... maybe it's listed in the book?
there may be a picture as well.

I'm not sure what kind of connector your dealing with..
but the coil ends are probibly like a car and you trim the rubber back abit then
fold the core on to the outside of the wire and slide the connector on and tighten it down a little, so it stays on and will slide down into the coil nicely.

i found this much for you in the tech tips section.

These coils will work with all years of our bikes, 78-81, and the 82-84 XJ11's as well. With the earlier years that use the ballast resistor, you'll just need to remove and bypass the resistor so that the coils can get their full 12 volts power. With the 81 XS and later XJ's, it's just plug and play.
http://www.xs11.com/forum/showthread.php?t=12452

but he was talking about the black coils...??

[CA]

Thanks Mindwebs, I didn't read that as closely as I should have. I was concerned about the differences between the green and black coils since there is some noticeable ones. As for the ballast resistor I can actually remove it and just plug the two wires that were going to it together correct? Funny thing is I used to think that thing was a gas gauge of sorts....don't ask.

Yet I was under the impression that a coil fired cylinders 2 and 3 and another 1 and 4, that is at least how the stock was set up I know that for sure.

That MikesXS warning of warranty has me a little scared

[tcoop]

CA Before you hook those coils up double check the maual for configuration because I too thought it was 1 and 4 on one coil and 2 and 3 on the other. (This is how my XJ is I have not looked that closely to the xs11's)

[dbeardslee]

I got the black 7mm plug wires from Mikes and am a little confused how they hook into the coils.

The coils come with four copper wire ends clips. You'll see a little triangular shaped hole in the clips. Strip about 3/4" of the high tension wire, and insert the bare wire through the triangular hole, and crimp the connector on the wire. Allow the wire to fold back such that it's in between the clip and the coil socket. That's the way Mikes XS said to do it - I had the same question .

[CA]

so I am in the garage and just finished the instal of the new coils...removed ballast resistor and connected the two wires. Pushed ignition and nothing...

help?

[bikerphil]

Any dash lights on with the key? Turn your kill switch to on position.

[CA]

Yes and yes. Lights on kill switch on. and absolutely nothing.

Here is what I did:

removed battery.
dismantled coils.
mounted new green coils with new plug wires and caps installed. coil 1 to cyl 1 &4 and coil 2 to cyl 2&3.
red + wires screwed in on bottom of coil
green - wired screwed in on top of coil
removed ballast resistor - two remaining wires had male and female ends so I just plug them into each other.
installed battery
turned on, hit starter and absolutley nothing
checked battery, 90%
hooked up ballast resistor (just curious). nothing happened.

SO I suppose that since the starter isnt turning so its obviously electrical and has something to do with what I did. I should say last time i rode I believe my coils completely failed, I was riding and it dropped down to two cylinders and finally wouldnt start. Stranded me and my girlfriend. Yet the starter was turning through all of that....

I will do some reading on troubleshooting similar issues but any help will be appreciated.

[dbeardslee]

Did you check the fuses? Your saying the starter isn't engaging either, right? I just had a similar problem that kind of came out of the blue. It wound up being in the starter button - I think. For some reason, I was able to jumper a wire from the hot connection on the starter solenoid to the solder connection for the red/wht on the solenoid. With the jumper in place I was able to start it using the button, and it ran as long as the wire was in place. Remove the wire and it quit. If yours acts the same way, you'll know to look for the problem in the red/wht wire.

[petejw]

jat,
have you got the tip over switch
positioned the right way?