R69 (and other) field coil repair?

[Werner1111]

10-4 Tommy. Thanks for the support buddy!

[Werner1111]

I finally got to work on the coils again today. I wound the first coil, using 20 AWG wire, instead of 19 AWG. It looked like hammered dog$*%t, as my friend used to say. The spool was a bit too wide for 10 wraps of the new, reduced diameter wire, and the wire did not lay down very neatly.

I told myself that if this didn't work, I was going to give up and just buy the dang replacement parts. Thankfully, I printed another spool that was just a bit narrower, and that did the trick. The wire laid down nice and neat. With the slimmer coil, I can now snug down the shoes and easily slide in the rotor. Phew. I only got three wound today, but I'm pretty sure I'm on the right track here. Hopefully I'll knock out the fourth shortly and can start putting things back together.

[Werner1111]

It's alive! And it works! I was finally able to get everything back together over the weekend and the bike now charges. Well, at least the charging light goes out when I rev the bike. I haven't yet done any more formal testing. Here's an update with pictures.

While there are four part numbers for the various coils, they are the essentially the same. However, the coils must be set up such that the windings are situated clockwise, counterclockwise, clockwise, counterclockwise in the ring, which creates the N S N S magnetism needed to implement the generator function. The counterclockwise coils are not wound in reverse to the clockwise coils. They are identical. Instead, the difference is the way the counterclockwise coils are connected to their neighboring coil. Imagine four people standing in a circle holding hands. The hand connection would typically entail person one's right hand to person two's left hand and then person two's right hand to person three's left hand, and so on. To get the counterclockwise winding, imagine that two of the four people, standing across from each other (say person 1 and 3), crossed their arms to connect to their neighbors. They would connect left hand to left hand and right hand to right hand. This is a simplistic way to imagine how the direction of the current is reversed into a counterclockwise direction. If that's still difficult to visualize (it is for me) I show it in action in the 2nd picture, below. The other minor differences is that the first and last coils have pigtails for connection to the voltage regulator and 61. The long wire goes to the voltage regulator and the short end goes to 61 on the stator.

I wired the coils together using yellow heat shrink because it mimics what comes from the factory.


You can see in the picture below that the wires in 2nd and 4th coils are connected to their neighbors with uncrossed arms. The 3rd coil is crossing its arms, as is the 1st, but it's less evident. Hopefully you can trace the current and see how it travels clockwise vs counterclockwise, changing the polarity of the coil.


Installed in the stator.


I replaced the F-type voltage regulator with a solid state model.


Heeding Vech's words, I kept a close eye on the clearance between the rotor and the stator - specifically the shoes holding the coils in the stator. Given that, I'll share my methodology and a few pictures about that part of the assembly.

I took multiple measurements with both my calipers and a bore gauge to make sure there was enough clearance. First, I took measurement with my calipers to find the distance between the inside of the shoe face and the outside of the stator body (simply as a reference point). I found that if the shoe wasn't aligned straight up and down, but slightly cocked, one side of the shoe would stick out towards the center more than the other. While the curved base of the shoe is shaped such that it should register on the curved stator body and align straight up and down, with the coil in place, it wasn't always straight forward. There still was some interference from the coil, so double checking by measuring was important for me.

I checked the right side of the shoe face here.


Then I checked the left side of the shoe face here.


I also employed a bore-style gauge to check the clearance between the shoes at multiple points. The OD of the rotor is 65 mm and the ID of the shoes is somewhere around 66 mm, so there isn't much room for error. Well, if you're an aspiring machinist, 1 mm is practically the Grand Canyon, but it felt very tight to me all things considered. I would routinely test the fit by placing the unmounted rotor inside the stator and, while I could tell there was clearance, it was impossible to tell if there was enough clearance on all sides by this simple test. Hence, the measurement with the calipers and bore gauge.




Once I was satisfied that there was enough clearance, I installed the rotor and then the stator onto the front of the engine.


I turned the motor over very slowly, first using the bolt on the end of the crank shaft, and then the kick starter once I was convinced that there was enough clearance. Finally, I started the bike and the red charging light went out when I revved the bike. It is on when the bike idles, but goes out when the bike revs up just a bit.


I took the bike for a ride around the block and everything worked, though I think I need to check the timing again (I had to overcome the bike's differential timing) and maybe rebalance the carbs. Here's my bike happily resting after a neighborhood jaunt.

I bought this 1960 R69 as an unfinished restoration. Unfortunately, the prior owner passed away prior to finishing the work and the charging system was still on the list for repair. I continue to replace polished parts with those having the factory finish. Replacing the front brake plate and the final drive are future projects.



One last bit. Doug Rinckes has a post asking members to submit the order of polarity of their coils on their pre-1970 bikes. I will post on that thread next, but I will also say here, that my coils seem to have the opposite polarity of what was reported by James and Tommy. I thought about this a lot to make sure I was not in error, but I'm convinced the polarity of my coils is the opposite of what others posted.

[jwonder]

WOW!!! Very great thread! This is a wonderful experience and its great to hear that it worked. You should be proud of your efforts and the outcome.

[Werner1111]

Thanks James! I certainly have appreciated your support and the help of the other nice folks here. I hope this is helpful to someone one day... and not because the coils are no longer for sale.

[808Airhead]

Congratulations on your reward for all that effort. These bikes require a lot of love, but once sorted, reward us with stellar service.

[wa1nca]

Great work glad you didnt give up
I learned a lot
Beautiful bike
Enjoy
Tommy