Dynacoil Help???

[Ctino]

I am wanting to change my coils for the dynatek minicoil. As ive fitted a r90 tank and the minature coil should fit nicely. I dont know which one to go for, my bike has the bosch dual output coil its an 81. I mailed the guys at http://www.dynatekuk.com/index.html with the make/model and they couldn't figure it out.
Im a newb so any help much app....

This is the reply i got :
 
I am struggling to find any data on the bikes coils, as I do not have any information in any of my data books.
 
Also, the "81 model also seems to be a bit of a cross-over year. I need to know exactly what ignition is on the bike and if possible what is the primary resistance of the coil which is originally designed to be fitted to this bike.
 
Regards Richard.
 
Richard Redmayne
Dynojet UK
01995 600 500
richard@dynojet.co.uk
www.dynojet.co.uk

[Bob_Roller]

Not familiar with that series of DYNA coils, but you need a 1.5 ohm dual output coil for bikes equipped with OEM electronic ignition system , if they have them .

What are the last 7 characters of the bikes VIN, that will tell you for sure what year you have .

Post the numbers here, it's a quick check to figure it out .

[Ctino]

Cheers PM'D my vin num...

[Ctino]

There are three BMW Airhead ignition coil configurations:

1.  Points and Condensor
==========================================================================
Two, 6-volt 1.5 ohm primary resistance. 6500 - 7000 secondary, single tower coils wired in series, for points ignitions.  There were three versions of these original "Black" Bosch coils:
BMW #: 12 13 1 351 584  Bosch part #: 0 221 100 022 (/5)
BMW #: 12 13 1 243 452  Bosch part #: 0 221 101 003 (/6, /7, early 100)
BMW #: 12 13 1 244 142  Bosch part #: 0 221 100 028 (R80RT, R100/T, R100CS, R100RS, R100RT)

Used on all Airheads from September, 1969 through July, 1981.
All /5, /6, R90S, early /7, early 100s (R100, R100S, R100RS, R100RT, R100T), early R80 and early R65

Some people replaced these with the Bosch "blue" coils, 1.4 ohms, single tower, which are no longer available.  They have been replaced by: Bosch part #: 0 221 124  001  - 15k secondary  (Brazilian "silver").

These two coils could have been replaced by a single Accel 140403S dual tower coil, or single Dyna "green" 3 ohm coil.

Some users added a Dyna DBR-1 points amplifier to the stock points and condensor configuration.  Since the DBR-1 also wants to "see" 3.0 ohms, the coils remain the same.

Some users replaced the points with an electronic ignition.  Lucas, Gerex, and Silent-Hektek all make (or made) electronic ignitions to replace the stock BMW points, but the most common vendors
are Dynatek with their "Dyna III" D35-1 ignition and Boyer Bransden with their Mark III and  Boyer Micro Mark III electronic ignitions.  All these systems expect to "see" 3 ohms primary coil resistance, i.e., one 12V 3 ohm coil or two 6V, 1.5 ohm coils wired in series.

Dual plugging points and condensor ignitions was often done originally with Andrews coils (.7 ohms, and unreliable as reported by Oak) and Accel points amplifier (no longer available).  The more common setup today is with two Dyna Dynatec DC2-1 (brown) coils.  These are 6-volt, 1.5 ohm primary resistance, twin-tower coils.

A Dyna DBR-1 points amplifier can be added to this configuration, with no change in coils.

Dual plugging with stock points and condensor can also be done using two Dyna DBR-1 points amplifiers, each driving a 3 ohm dual tower coil, either two Accel 140403s or two Dyna DC6-1 (green) coils.  

A final dual plug option was to use a three wire Dynatek D35-1 electronic ignition feeding two independent dual-tower coils of 3 ohms primary resistance, either two Accel 140403 coils or two Dyna DC6-1  green coils. There coils are not wired in series.


2.  Early Electronic Ignition
===========================================================================
Two, 6-volt .7 ohm primary resistance single tower coils wired in series,  for old style electronic ignition (white or pink lettering)
BMW # 12 13 1 244 142  
Used on late /7, late 100s (R100RS, R100RT, R100T, R100CS), late R80, early R100S.  These are the black coils with the yellow lightning bolt icon.  These coils were specifically designed for Hall-Effect ignition triggers.  Can be replaced with a single Dyna "brown" 1.5 ohm dual-tower coil.

Dual plugging this configuration was often done with two Accel 140404S coils. These are 6-volt, .7 ohm primary resistance, twin-tower coils.   The Accel 140404 is the two coils in one kit.

This configuration should not have a points amplifier, single-plugged or dual-plugged.



3.  Late Electronic Ignition
===========================================================================
One, 12-volt, 1.2 ohm, twin tower coil for new style electronic ignitions.   Used on R100R, R100 Mystic, R80GS, R80ST, R100GS, R100GSPD, late R100RS, late R65, late R100S.
The early gray version BMW #: 12 13 1 243 910  (Bosch # 0 221 500 200) after 1984, problems from cracking and the secondary windings opening; this is seen as early as the 1983 R80ST/GS. (Note from Snowbum).  The updated black version  BMW #: 12 13 1 244 426  (Bosch # 0 221 500 203) is okay, but BMW says requires a new ECU (with same part #, but with turquiose lettering instead of the previous verion's white or pink lettering).

A failed coil was often replaced with Dyna DC2-1 (brown) coil.

Dual plugging was often done with a pair of ACCEL 140404 coils or a pair of Dyna DC9-1 coils, wired in series.

This configuration should not have a points amplifier, single-plugged or dual-plugged.

One, 12-volt, .6 ohm ohm primary resistance  twin tower coil for new style
> electronic ignitions.   Used on R100R, R100 Mystic, R80GS, R80ST, R100GS,
> R100GSPD, late R100RS, late R65, late R100S.
> The first single 12 volt two-tower GRAY coil
(I have not put down here the various types of modules, whether or not they have to be used, and so on.)

[Bob_Roller]

The bike is a European model (but you already knew that !!!), manufactured in 11/80 .

A manufacturing start date of 09/80, started the '81 model year bikes just so you don't get confused and think it's an '80 model year bike .

This was the start of many changes to the R65, so if you go to a parts catalog, you may see references to this date, 09/80 for parts effectivity .

 For parts, it's an '81 model year bike .

You have the factory electronic ignition system .

[Barry]

The dual output coil was never fitted to points bikes so yours really is 81 electronic ignition.  

The mini coils in the picture are not the correct resistance though they might sort of work. They don't in fact make the correct mini series coil for your application.

 
If the standard coil will fit you want the Dyna DC2-1 brown coil which is 1.5 ohms.

[tvrla]

I don't know that it'll make much difference going with a higher resistance coil than original. The spark may be just slightly weaker, but then again it might not be at all noticeable. It definitely won't hurt anything to run a higher resistance coil. You just don't want to run lower resistance since that could over-work the ICU.

[steve hawkins]

I run a BMW K100 dual output coil on my 79 R65 which replaced a pair of Bosch Blues which had broken both coil mounts on my frame as they were too heavy.  The K100 coil was sourced second hand from Motorworks and it was their idea to give it a try.

Works like a charm although there was a bit of fabrication to mount it.

Cheers

Rev Light

[Barry]

Steve,

What are you driving that K100 coil with ?

The  primary resistance is surely not more than 1.5 ohms which if points are used is usually reckoned to be too low for a long life.

[steve hawkins]

Its a points ignition.  Standard.

Never had any problem with it.

Cheers

Rev.Light

[Barry]

That's interesting.

If the K100 is a viable alternative maybe I could use one. My points ignition amplifier is rated for a maximum of 4 amps but it runs very cool so I think it could take a little more. I'll try to find out what the K100 coil primary resistance is.


Edit

I'm getting mixed views on the primary resistance. One source says  2.6 Ohms which is similar to the stock 6 Volt pair on a point set up and another source says less than 1 ohm.  Maybe the K Bikes coils changed over the years just like airhead coils did. Odd that BMW may have used a lower output electronic ignition on the K100 compared to the later airheads.

[tvrla]

The K coils did change over the years - at least the external connections. I don't know about the resistance. Look for an early K100 coil, it'll have the spade terminals common to our bikes. Newer ones require an odd plug with bullet type connectors.

[steve hawkins]

It would probably be an early type then as I do not recall having to do anything special with wiring.

I just had to modify the mounts on the coil so I could hang it from the relay tray on the front left of the frame spine.

It might be that it is of the low resistance type, but its been on there for 5 years or so.

I was just looking to do the job cheaply, although it would not be cheap if you bought the coil new!

Cheers

Rev Light