R80ST dual coil mounting

[maverickbluer1]

The 1983 R80ST I bought had been partially modified into a cafe racer. It had been dual plugged. It had two coils mounted on it but I didn't take a picture. Also, it didn't have a stock tank so I think there was more room. I'm having a hard time finding a location for the second coil. Has anyone mounted two coils on this model? If so, would you share pics or let me know where you mounted the second one?

Thanks

 

[20774]

Typically the two coils are mounted nose-to-tail on the underside of the backbone. Of course, a lot depends on the type of coil. Motorrad Elektrik has a variety of dual plug coils on their website:

Motorrad Elektrik - Keeping your Beemer charging along since 1989! (256)442-8886 or Motoelekt@mindspring.com

Anton has some discuss here: http://largiader.com/articles/ignition/

 

[maverickbluer1]

Thanks for that. I'm using the Duralast coils from EuroMotoElectrics. I also got one each of their brackets. One of the coils fits just fine in the stock location near the front on the stock mount on the right side of the backbone. It's the second one I'm not finding a great location for.

EDL-Coil 1.5 OHM - Dual Tower Coil for BMW Airheads & Moto Guzzi ; 1.5 Ohms Resistance Coil. EnDuraLast

Premium Quality Aftermarket EnDuraLast Coil for BMW, Moto Guzzi and other motorcycles. Includes 1 dual tower coil 1.5 ohms resistance.

www.euromotoelectrics.com

Coil Mounting Bracket - BMW and Moto Guzzi / Dyna

Dyna-CoilDCB-1 Dyna coil mounting bracket. BMW, Moto Guzzi, and others. mount Dyna ignition coils

www.euromotoelectrics.com

Coil Mounting Bracket - BMW and Moto Guzzi / EnDuraLast

Coil mounting bracket. BMW, Moto Guzzi, and others. Mount Dyna style ignition coils

www.euromotoelectrics.com

 

[52184]

On my ST the second coil is mounted on the RH side of the frame tube, directly across from the LH coil. IIRC I used the DCB-1 bracket on both sides.

Best,
DeVern

 

[maverickbluer1]

My ST doesn't have an LH coil. Would it be possible to get a picture of your setup?

 

[52184]

It may be a day or two before I could get a picture.
The OEM coil for the R80ST is a single dual-outlet coil that mounts via two bolts to a tab that projects downward from the bottom of the main upper frame tube, near the front. Mounting the EDL coils requires two DCB-1 brackets, one mounted on each side of that frame tab using two 6mm bolts that pass through both brackets and the frame tab. The coils end up tucked in close to the main upper frame tube and partially underneath that tube. This mounting allows the stock ST tank to fit and the coils pretty much concealed by the tank.

I’ll try to post a photo in the next day or two.

Best,
DeVern

 

[maverickbluer1]

Thanks DeVern. Photos would be greatly appreciated. I'm still having trouble with the left coil.

 

[20774]

Maybe some ideas here? I can't tell if this is for dual plugs or not:

Coil Mounting Bracket - BMW and Moto Guzzi / EnDuraLast

Coil mounting bracket. BMW, Moto Guzzi, and others. Mount Dyna style ignition coils

www.euromotoelectrics.com

Ooops...I see this was linked above.

 

[52184]

Here you are, and I stand corrected-the frame tab is actually on top of the smaller upper frame tube, not the bottom of the larger top tube. That’s what I get for going by memory…

Left side, tank on:


Right side, tank on:


Left side coil mounting:


Right side coil mounting:


It’s not clear in the pictures, but one lead from each coil goes to the cylinder on the opposite side.

HTH,
DeVern

 

[20774]

Snowbum's suggestion for plug wiring is to use one coil to the top plugs on each cylinder and the other coil for the lower plugs on each cylinder. This way, if you have a coil failure, the remaining coil is still powering the cylinders. He has other reasons for this related about 2/3 down this page:

Dual Plugging, dualplugging, BMW Airhead Motorcycles

Dual-plugging BMW Airhead Motorcycles

bmwmotorcycletech.info

 

[52184]

Snowbum's suggestion for plug wiring is to use one coil to the top plugs on each cylinder and the other coil for the lower plugs on each cylinder. This way, if you have a coil failure, the remaining coil is still powering the cylinders. He has other reasons for this related about 2/3 down this page:

Dual Plugging, dualplugging, BMW Airhead Motorcycles

Dual-plugging BMW Airhead Motorcycles

bmwmotorcycletech.info

Yes, exactly as I have them. The lengths of the wire kits sold by EME and others makes that a simple setup.

Best,
DeVern

 

[20774]

OK...I had to reread your description of cable routing a few times to make sure I understood!!

 

[maverickbluer1]

Here you are, and I stand corrected-the frame tab is actually on top of the smaller upper frame tube, not the bottom of the larger top tube. That’s what I get for going by memory…

Left side, tank on:
View attachment 97267

Right side, tank on:
View attachment 97268

Left side coil mounting:
View attachment 97269

Right side coil mounting:
View attachment 97270

It’s not clear in the pictures, but one lead from each coil goes to the cylinder on the opposite side.

HTH,
DeVern

Great thanks for those pictures. I finally found the original bracket that was on the bike when I got it seems to be workable. It appears to be a custom bracket that mounts both coils with spacers in between to separate them. They are very close to the top cover. it does bolt on at the original coil mounting location.