Vintage BMW Motorcycle Owners

Hi guys! So im restoring a BMW R26 and it didnt have the field coils. I bought the field coils from Tim Stafford but I dont know how I should connect one to each other. Im having headaches with this thing for long know. Please any help help will truly appreciate it because I want to keep the bike original and I cant find any information about this topic.

Best,

Martin

This is how they are supposed to be wired together.
NOTE that the field coils are (should be numbered) and MUST go in the positions shown in this diagram. this is viewed from the rear.
An Important HINT:
you simply do not install the each steel pole shoe through each winding, and simply tighten up the screws holding each field shoe in the housing. Install the windings, with the shoes but do NOT tighten the screws yet. Take the armature, and wrap it with a long strip of paper (to increase the diameter of the armature, and put enough wraps of paper until it is a snug tight fit inside the 4 steel shoes) then tighten the screws. If you find the armature has loosened way up, remove it and add more wraps, get it back inside the field shoes, you may have to loosen the screws a little, but be sure you can get the armature fully inserted inside the shoes, with a tight fit of the paper. Then re-tighten the field screws and see if you can pull the armature back out with the paper. The idea is that using the paper to increase the diameter will force the shoes to correct alignment over the armature, insuring that when the paper is removed the armature will have clearance in the field shoes.
Check by installing the armature on the crank, and then install the field and very very slowly, rotate the crankshaft. Take the field back off and look for ANY witness marks that indicate the shoes are touching the armature. If the shoes touch the armature when running, it will destroy the armature instantly!

As informed by Vech, need to be sure that coil brackets didnt touch armature rotor.

Check run out of rotor, move engine by hand and check again if there is any shinny spot, meaning that is touching.

Coils must be connected to change polarity between them, as you can see on Vech´s drawing, in order have North, south, north and South magnets.

Tim´s coils are just one part number, so need to be sure which type of coil does it have supplied, (sadly I bought 4 for Tim and USPS delivery on wrong address), but any type supplied can be modified to work correct, just need to understand what you have.

Post some pictures and could give you some advise..

regards

Rodolfo