magneto horseshoe washer

I have a lucas K2F magneto auto advance unit that is missing the horseshoe washer. Where is a good place to buy this or, I will make one if someone knows the thickness.

FYI - the part number is 498131, and the name is "clip".

If you want to fab one up, I do not see why the thickness would be critical ... any thickness from 0.040 to 0.062 should do nicely.

Slick

Thanks. I had no idea how think it should be. It.s been a few decades since I last worked with a magneto. I just bought a Joe Hunt for my P11/trackmaster project.

would like to strip the AAU for a good cleaning. however the big nut does not want to come out. It slides back and forth and turns easily but will not come out. I soaked the whole thing in WD-40 and it appears to be in good shape...everything moves in and out OK. Before I use more force, is there a good reason that the nut will not slide out?

seattle##gs said:

Thanks. I had no idea how think it should be. It.s been a few decades since I last worked with a magneto. I just bought a Joe Hunt for my P11/trackmaster project.

would like to strip the AAU for a good cleaning. however the big nut does not want to come out. It slides back and forth and turns easily but will not come out. I soaked the whole thing in WD-40 and it appears to be in good shape...everything moves in and out OK. Before I use more force, is there a good reason that the nut will not slide out?

Click to expand...

The securing bolt (nut you refer to) has an internal left hand thread. This is for self extracting the AAU off the tapered magneto shaft.

Try turning the bolt clockwise while gently pulling on it. If it does not come off, it is because the internal LH thread is stripped (a common occurrence).

If the AAU has no binding or "sticking" when you advance the flyweights, there is no need to dis-assemble it, unless you believe there is undue wear in one or more parts.

Slick

The securing bolt will slide back and forth about 1/2". The securing bolt must screw on to the magneto. The bolt must have an internal thread for this. Then it must have an external thread for the puller side of its function? If the bolt has stripped its puller threads it will no longer act as a puller? Then how do I remove the AAU? It looks as thoug the previous owner has used a two jaw puller at one time because the large round plate is bent but not enough to damage the unit. What strips first, the threads in the body or the threads on the bolt? If it's just the bolt I can replace it and regain the extractor function. Who sells these bolts?

seattle##gs said:

The securing bolt will slide back and forth about 1/2". The securing bolt must screw on to the magneto. The bolt must have an internal thread for this. Then it must have an external thread for the puller side of its function? If the bolt has stripped its puller threads it will no longer act as a puller? Then how do I remove the AAU? It looks as thoug the previous owner has used a two jaw puller at one time because the large round plate is bent but not enough to damage the unit. What strips first, the threads in the body or the threads on the bolt? If it's just the bolt I can replace it and regain the extractor function. Who sells these bolts?

Click to expand...

Yes, yes, yes, yes, and yes to your first five sentences.

My extractor bolt is stripped, or as you point out, it may be the threads in the body. Dunno which goes first. I have a steel sprocket on the AAU which I can pull on with a 2 inch gear puller (it may be necessary to grind one claw thin enough to get behind the sprocket on the left side). If the AAU is fitted with a fiber sprocket, it will be damaged if you pull on it.

I undo the securing bolt about 1 - 2 turns, grab the sprocket with the claws, and push on the bolt head.

I have tried unsuccessfully to get my bolt out of the AAU. If you figure out how to do it, let me know. It seems to me, one would have to cut the head off the bolt. Further disassembly requires a press.

I once found a source in the UK who sold the bolts, and also did a complete rebuild of the AAU. That source escapes me now, but if you were to Google Lucas AAU repair in the UK, I am sure something will turn up.

Let us know how it turns out.

Slick

By a very strange coincidence, someone dropped by and gave me a defunct K2F with a very good AAU attached. Gave...as in FREE. The extractor bolt was in good condition and screwed out easily. The horseshoe washer was there. I think the threads on the bolt would be the first to give way since there are only two of them.