Sign in to follow this  

Wanted info - Early Bosch Ignition/Mag Switch

Recommended Posts

I want to use this switch on my project . The motor has a Bosch DU-6 and a separate timer. The motor has 12 spark plugs. I know I can  start on battery and switch to mag  but can I also wire it to run both sets of plugs.(Mag and battery ignition at the same time? 

bosch switch 2.jpg

bosch switch 1.jpg


Edited by mikewest
correction of my thoughts (see edit history)

Share this post

Link to post
Share on other sites

It will certainly work to start on battery and run on mag but I'm not sure how you'd get it to run both sets of plugs simultaneously... you really should do that too as it's a huge T-Head and they have a notoriously poor combustion chamber. It's best to have one ignition timed ahead of the other just a tiny bit too. I'll see what I can find on this.



Share this post

Link to post
Share on other sites


Your switch is a vibrating duplex. Not to be confused with a duplex switch/coil used with a duplex magneto.

Bosch terminology of that period is quite complex.

Your switch was used with a vibrating duplex coil ( shaped like a Derby hat) to make an independent magneto such as your DU-6 start on battery and run on magneto.

I doubt that you can adapt it to run 2 sets of spark plugs, surely not 3 with a timer.

I have a large collection of Bosch literature as well as magneto ignition pieces. Contact me if I can be of help.

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this