XS11 Dyna Coil upgrade

[charlie23]

Hey guys, I have recently acquired an '81 XS11 Midnight Special (?) that has been tinkered on excessively by previous owners who were not particularly adept at tinkering. I've been working through various electrical gremlins, the most recent being a dead short in the RW line from the (stock) fuse box to the coils.
A resistance test on the coils (I think not stock) leads me to assume they're either shot or below spec.
I have a spare (2nd hand) set of Dyna DC2-1 coils which are going in as per the info at http://www.xs11.com/forum/showthread.php?t=4868 along with new (proper) wiring from the 2pin connectors on both sides.

There is no ballast resistor on this bike, and the manual I have says almost nothing about it. I'm in Bulgaria and the OEM part is not available locally; shipping costs make Ebay prohibitively $$$. Is the resistor necessary with these particular Dyna coils and if so does anyone know the specs (or maybe a specific non-OEM substitute)?

Also I'd like to thank you guys for admitting me to the forums, the info here has been extremely useful during this project
Thanks,
Charlie.

[natemoen]

When looking up those coils I am getting mixed answers but most places seem to say that those coils are 6 volt coils and that they are 1.5 ohm coils.

If that is true they absolutely will not work since they are 6 volt coils.

As to the ballast, the ignition system on the XS11 is a 3 ohm ignition system. The early models came with 1.5 ohm coils and then used a 1.5 ohm ballast resistor to give the ignition system the needed 3 ohms. On the later models the ballast resistor was removed and 3 ohm coils were used. Since you have an '81 then you would not have the ballasye resistor. If you swap coils you need to use 3 ohm coils.

[jetmechmarty]

I believe you need Dyna DC1-1

OEM: DC1-1 - DYDC1-1. 3 ohm green coils. OEM: DC10-1 5 ohm 12-volt black coils. Replacement for factory coils. Fatter spark means smoother running and less chance of fouling a plug.
See below for plug wires.
Check the resistance of the coils you are replacing to ensure a correct match.
If you have questions if these are correct, please call us or Dynatek at 1-800-928-3962
Never select a coil with a lower resistance than your ignition system - this will cause the coils to overheat and burn out... It is OK to select coils with a slightly higher resistance. For example 3.0 ohm coils with a 1.5 ohm CDI ignition. While this isn't optimal, it works and allows you to switch your CDI ignition over to a Dyna-S in the future.

If the bike was run with coils at too low resistance, the TCI may be damaged.

[TopCatGr58]

Hey Charlie,

The guys have already chimed in with the info. The coils you have are not necessarily 6 volt as much as 1.5 ohm. Here's the Dynatek webpage:
http://www.dynaonline.com/skins/prod...es/Dyna_Coils/

Here's the TECH TIP on using these coils on our bikes.
http://www.xs11.com/forum/showthread.php?t=4868
However, even though the tips says 6 volt, the BOX just shows 1.5 ohm, but no real specification of voltage because they can operate over a fairly wide range of voltage. The OEM system for the bikes 78-80 with the 1.5 ohm ballast resistor(BR) drops the continuous running voltage down to about 9 volts. During starting, the B.R. is bypassed sending 12 full volts for a stronger starting spark.

The 81 series did away with the BR and used coils with 3 ohms so the TCI would see the full 3 ohms resistance vs. the earlier TCI's with the BR that had 1.5 ohms for the BR and 1.5 ohms for the coils for a total of 3 ohms.

The reason why I'm stating this is to help you understand what may have happened to your 81 TCI....too little resistance with those 1.5 ohm coils, which drew too much current from the output transistors which would then overheat and burn them out. This can be a reason for lost spark due to the TCI not being able to control/switch the coil(s).

The 81 coils get the full 12 volts from the harness ALL THE TIME. You said it had a dead short in the RW line to the coil? Did you mean that there was NO power(12V) when measured at the coil with the key on??

Anyways, it would probably be cheaper to get a 1.5 ohm BR and put it IN LINE with the 12V line to the coil and then see if the bike will run, and if you get spark on all 4 cylinders. BTW, to check spark the spark plug can be out of the engine, but needs to be grounded to the cylinder head so the spark can travel thru 1 coil wire, spark plug, engine, the OTHER spark plug, wire and back to the coil....both wires fire at same time and need the complete circuit to fire. IF you just hold the coil wire/plug in the air, you will NOT see a spark!

The 81 series are LESS prone to the Pick Up Coil wires problems in so much as I've never seen a failure reported on here of them, only the earlier 78-80 year bikes. The 81 TCI is more special because it has the cent. adv. timing curve programmed into it instead of using the mechanical parts to control that. This makes the TCI more rare, as well as not repairable if it goes bad.

If after trying to get the bike running, and you don't have spark on 1 pair of coils, first swap the controlling trigger wires..ORange and gray and restest. IF the previous dead coil sparks, but the previous good coil now is dead, then there's a good chance the TCI is damaged. You'll need/to test the PU coils just to be sure.

IF the TCI is fried, you have a few options. Being in Bulgaria being able to acquire an 81 4RO series TCI will be very difficult and $$$. The other option can be to get the Mechanical advance components from an earlier model 78-80 bike and transplant them to your machine. THEN you can acquire an earlier model TCI 78-80 to use....OR you can even build your own from automotive components which might be easier/cheaper to acquire...see the tech tips on how to do that.

Okay, a lot of info to digest....good luck!

T.C.

[charlie23]

Hey Charlie,

...The 81 coils get the full 12 volts from the harness ALL THE TIME. You said it had a dead short in the RW line to the coil? Did you mean that there was NO power(12V) when measured at the coil with the key on??

Actually the fuse was blowing whenever I hit the ignition, traced the DS to the left hand coil. I have already mounted the Dyna's and do have clean spark on all 4 cylinders, the bike runs and TCI does not appear to be damaged. I'll wire in a resistor before proceeding further. Thanks for the input!

[Meista007]

I just made the switch to Dyna coils as well and while install was easy I do still have one question (possibly a dumb question).

How do you know what cylinder goes to what coil socket? I know what cylinders go to each coil but I don't know if it matters what socket they go in.

My guess is that since nobody ever mentions it it doesn't matter but I would like to know for sure before I cut my new wires.

[bikerphil]

1 and 4 go to the coil with the orange trigger wire, 2 and 3 go to the coil with the gray trigger wire. Both plugs (1+4 and 2+3) fire at the same time, the one that isn't on the compression stroke is wasted.

[Meista007]

Thank you, I figured as much but wanted to be sure.

[James England]

If you check threads I've posted in the past, you'll see a pictorial on how to mount the coils etc...

[Meista007]

I ran through it already and it helped a ton, its nice not having to invent the wheel again for every project on the bike.

They are installed and ready to go.

(Also just got the call form the powder coater and my parts are done!)

Anyone have spark plug recommendations?

[jetmechmarty]

Anyone have spark plug recommendations?

Use the NGK BP6ES. Everyone should concur that those will work, even though options are available.

[3Phase]

... Anyone have spark plug recommendations?

Meista,

It depends on what type of spark plug wires and caps you use.

With resistor wires/caps use the NGK BP6ES.

With non-resistor wires and caps use BPR6ES unless you want to annoy your neighbors and bring down satellites from orbit.

.

[IanDMacDonald]

I laughed out loud reading the above post, thanks Scott.

I do have a question though: I read that having resistor/non-resistor has no effect on the running of the bike, true? So, with that being said, how much of an issue would it be to leave the resistor in the caps, and use the resistor Irridium plugs?

[3Phase]

I don't know, Ian, I've never run my bike that way long enough to notice anything one way or the other about using resistor wires/caps with resistor plugs.

The set of Champion spark plugs that were in the engine when I bought it were resistor type, 10K Ohms, and they seemed to work fine with the stock resistor caps, non-resistor plug wires and stock ignition coils. I imagine it was relatively quiet in the RF spectrum.

Roughly about the same time I put in the Iridium BPR6EIX(?) resistor plugs I also added a set of Accel coils and wires with non-resistor caps. I tried using the stock BP6ES plugs and it made spikey things on my computer screen and on the radio so I went back to resistor plugs. The stock coils may not have enough oomph (technical term) for Iridium plugs but the Dyna's will light you up in a heartbeat.

.

[IanDMacDonald]

Yeah, I was curious if I could disregard using the "copper slugs", and just try using resistor caps with the Irridium plugs.