G1 source coil DIY rewind

[bpg11]

Hey BuggiesGoneWilders,

I promised I would share my experience after I tried to rewind the source coil on my '82 Yamaha G1.

Long story short: There is likely so much that could be considered 'wrong' with my approach, after asking for any info out there I just decided to wing-it! I made a lot of guesses, it could've failed in many ways. In the end though.. it wasn't too bad, I learned a couple things that might help folks with this problem and best of all... it worked!

Short story long:

It started over here:http://www.buggiesgonewild.com/showthread.php?t=175327

I spent some time looking here and elsewhere for a part. I found some potential donor buggies but they all were a bit too much and a 4.5 h drive away. I knew Rickystator or RMstator might be able to wind them for me but I'm in Canada so it'd be a few hundo by the time I shipped it off and got them done.

So I thought... how hard can it be? I figured I would just send the metal core in to be rewound if I failed so...

1) I watched some sketchy youtube vids like: https://www.youtube.com/watch?v=Cm_dLW_fK8Q.

2) I guessed at the gauge of wire and went with AWG 36 based on a few threads about winding on a hobby RC site, smaller than this is apparently tough to work without breaking. I ultimately ordered this: amazon wire link

It was $30 shipped to me a couple days later. In retrospect I think I could've done it with 4oz, but that was already $10 and now I have a supply if needed in the future.

3)While I waited for the wire I tried to get the old coil unwrapped. I don't know exactly what they use to cement this thing together but it is bulletproof. I soaked in acetone, alcohol, I took a plumbing torch to it, nothing. Maybe there is a secret someone knows out there, but I cannot believe (at this point) that it would've been possible to count the number of wire wraps (typically recommended for rewinding). I ended up using a metal cutting wheel to notch the stuff and then used some needle nose pliers to pick off in cemented chunks, this was by far the worst part of the job!

Old coil with outer wrap removed (the wrap seemed like it was fibreglass tape):20210427_154748.jpg

Old wire chunks:20210430_131828.jpg

4) When the wire arrived I compared and I think it looked pretty similar! So I built a jig and prepped for the winding!

The jig -sorry this pic is twisted-:20210501_123303.jpg

I used JB weld clear(another RC hobby tip - apparently the normal stuff has metals in it!?) to seal off the metal core and sides as well as where I soldered the free end on to the ground lead. Once set I got to winding.

5) How much wire? I aimed for 350 Ohms. You can look it up but AWG36 has 415 Ohms / 1000ft. That means I'd need 843 feet. The kid and I marked our spool and pulled out 5 wraps measure and determined each wrap was roughly 6.10 inches (well we are actually in Canada so we did all this in metric = 257 m total and each wrap of the spool at 15.5 cm).

Either way we needed about 1658 wraps from the spool on to the coil. At this point I rounded up to 1700 to account for the spool getting smaller as we went, I didn't need to and we ended up with higher ohms (my manual does give 350+-10% and we ended up at the top of that range! I would've just stuck to 1658 if I could go back.

We marked the edge of the spool and Jr. got to count and tally while I ran the drill and would the coil.

6) We made it about 30 turns before the wire broke. I was tensioning too tight with my guide hand. Wire as thin as your hair is really brittle... go figure.

We restarted with me putting very little tension on the wire, this was the ticket!

I stopped every 500 winds and brushed a layer of JB weld on the wraps, this is important to secure the wires, and offer some protection from water or abrasion, The JB flowed nicely as we kept winding so layer on layer will be cemented together.

Once we hit 1700 I Ohm'd the coil and as mentioned above we were high! 400 Ohms at this point I would've liked to go back but the JB was setting and with the brittleness of the wire I decided we would just go with it!

7) I soldered on a new wire lead. I didn't have any fancy stator paper so I subbed a few layers of parchment paper. layered the lead and again sealed with JBclear. Finally I did a wrap of paper around the coil and finished with 2 wrappings of Nylon cord impregnated with JB.
20210501_152103.jpg

It looked pretty good and after attaching the lead and putting it back in the magneto Brown to Black Ohmed out to 382 - I guess we added a bit of resistance with the additional solder joint, wire, ground screw to the core etc.
coil after.jpg

We got it all back together and... it fired up for our first time! It has been running great for a few hours of runtime now. If it lasts, this is definitely a project most could pull off, I am by no means any sort of expert!

Maybe this can help someone out, and at least I hope this adds to the knowledge we have compiled here! Cheers!

[bpg11]

OK I got some pics figured out.

Here are a few more shots of the winding jig.

20210501_123306.jpg

20210501_123313.jpg

20210501_123321.jpg

winding jig.jpg

[cgtech]

That's awesome!

[bpg11]

Update: several weeks later. A couple longer 'rougher' runs and still going strong!

[AGELE55]

Love it !