Looking for a ignition coil

RustiePyles

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Does anyone know of a dual lead 2.5-3ohm (TCI Bike) automotive style coil like the one pictured below (it's a 5ohm)? Doesn't necessarily have to be chrome. I don't have a lot of room under my tank so I'm exploring different mounting options. I'll have loads of room in my "oil tank" but I don't particularly want to run plug wires that long. So I'd like to mount my coil between the front frame legs or on top of my rocker box (no head stay on this bike) I'm thinking a canister coil is going to be best option if I can find one.
3000140_A_V1.jpg
 
If you are planning to use it on a TCI or Gonzo box the 5 ohm coil will be fine. I tink the Honda or TCI coil will fit better.
 
If a 5ohm coil will work than that easy, 5omh dual lead can coils are cheap and plentiful. Yes I'm going to be using a GN250 module.
 
Can the GN250 run a 5 ohm coil? If it needs a 2.5 ohms coil it won't work.
I had acoil like that I ran with a dual lobe points cam. The coil worked well, the dual .obe cam didn't. The obes were off by around 7 *.
The Honda MP08 coils will fit in under the tank like stock with a bit of an adapter. These are well made and not expensive.
Leo
 
The TCI does not supply current to the coil like the condensers in a points system or a cdi. It simply grounds the coil with the current coming from the battery. A coil with too low of a resistance will cause a high current to flow through the TCI/Gonzo box possibly damaging the box. A higher resistance coil just causes less current to flow to ground through the ignition box.

Not sure why the 5 ohm coil would not work with the points setup. Perhaps a larger condenser is required with that high of resistance in the coil .
 
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Here's the Honda MP-08 and TCI coil for size comparison. TCI on the left. I've got the dimensions here Fletch if you need 'em. I mounted mine back on the front of the battery box. Longer leads don't seem to have any effect.


size.jpg
 
Here's the Honda MP-08 and TCI coil for size comparison. TCI on the left. I've got the dimensions here Fletch if you need 'em. I mounted mine back on the front of the battery box. Longer leads don't seem to have any effect.


View attachment 183217
:yikes: Jim, I had wrongly assumed that the MP-08 coil was the same size as an XS coil. I had only seen stock photos of them online with no reference for scale. That might actually work, and the mounting holes in the core are the right way up. I only have 1 15/16" (49.2mm) inside width in the tank tunnel though so even the smallest of coils is gonna be tight. My thought was that the auto style can coils are a little better looking, so if it had to be mounted in an exposed location it wouldn't be so ugly. But if i can fit an MP-08 coil under the tank I wont have see it at all. Not wanting long plug wires was more of aesthetic issue than matter of function. I know longer plug wires won't have any effect, but this is a bobber so form does outweigh function to certain degree.

I cant help but notice that all GN250 ignition modules are listed as being CDI and all the specs (I could find) for the GN250 itself list it as being a CDI not TCI?
 
I've been inside one and there is no capacitor. It's a marketing thing. In a CDI system the hot side of the coil goes to the cdi box and the other side is grounded. The power for the coil comes from the CDI box which in turn comes from ether the battery in a DCCDI system or coil in the stator which is a ACCDI.

TCI on the other hand works more like a points system where the positive side of the coil is powered by the battery and the TCI replaces the points to ground the the negative side of the coil at the right time .

The easy way of determining which system is which is if ether terminal of the coil is directly grounded then it's a CDI.
 
I've been inside one and there is no capacitor. It's a marketing thing. In a CDI system the hot side of the coil goes to the cdi box and the other side is grounded. The power for the coil comes from the CDI box which in turn comes from ether the battery in a DCCDI system or coil in the stator which is a ACCDI.

TCI on the other hand works more like a points system where the positive side of the coil is powered by the battery and the TCI replaces the points to ground the the negative side of the coil at the right time .

The easy way of determining which system is which is if ether terminal of the coil is directly grounded then it's a CDI.
Thanks! Makes sense.
 
I know it is clear as mud but it's the best I've got for a simple explanation.

There are of course other differences. The CDI systems generally work at much higher primary voltages (over 100 volts applied to the coil primary instead of 12v in a points or TCI system). That's why the resistance of CDI coils are much lower than a conventional coil.

I could spend a day on the pros and cons of ether.

The big advantage of both is that they can zap the coil with a lot more energy not being limited by the amount of power than points can take without burning the points contacts.
 
I don't like the angle at which the stock coil mounts. It jams the plug wires up into the bottom of the frame's main backbone tube .....

dnLyzHt.jpg


PVUvDAZ.jpg


Since the MP08 is smaller and needs little adapter brackets made up anyway, you can take this opportunity to change the mounting angle and remedy the situation. Raise the front of the coil so the plug wires run more in line with the frame tube .....

8jLc0Yh.jpg


FNXKQXX.jpg


ARWm3F3.jpg


In my eyes, the finished install looks and works much better than the stock set-up .....

c9kWv1W.jpg


hmzRBk1.jpg


o4DwpVj.jpg
 
I don't like the angle at which the stock coil mounts. It jams the plug wires up into the bottom of the frame's main backbone tube .....

dnLyzHt.jpg


PVUvDAZ.jpg


Since the MP08 is smaller and needs little adapter brackets made up anyway, you can take this opportunity to change the mounting angle and remedy the situation. Raise the front of the coil so the plug wires run more in line with the frame tube .....

8jLc0Yh.jpg


FNXKQXX.jpg


ARWm3F3.jpg


In my eyes, the finished install looks and works much better than the stock set-up .....

c9kWv1W.jpg


hmzRBk1.jpg


o4DwpVj.jpg
@5twins I no longer have a head stay bracket and I'm running a Wassell Peanut tank with a 49mm tunnel.
@Jim even the MP08 is a little to wide at the towers to fit inside the tunnel of my Wassell, but it does slightly widen in the middle so it could possibly fit. Do you have one laying around, I could swing by with my tank and see if it physically fits? The more I think about it the more I think I'm going to have to just put it in the oil tank and deal with the longer wires.
 
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upload_2021-9-13_15-57-12.png

Accel 140403 or Dyna DC1-1? Both are 3 ohm. Are both compatible with the TCI ignition found on '80 to '83 XS650s, or is a 5 ohm coil a better choice? I have a 0.7 ohm Accel but assume that will damage my TCI box.
 
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BTW, the Accel is considerably more expensive than the Dyna. My XS1100 has been running a pair of Dyna DC1-1 coils for a couple of years.

Can the TCI XS650 operate with copper core spark plug wires or is suppression core required?
 
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