Magneto Bearing Puller

[Micke S]

I have a bunch of bars that a company normally delivers to a lab for testing of chrome quality and dept. I use them for making special tools etc. This time I did a bearing puller for the inner ring of so called Magneto Bearings. The inner-races were sitting on a two stroke crankshaft that I'm rebuilding.

 

[FOMOGO]

I'm afraid that rod may not be reusable. Did someone forget to put oil in the gas? Nice work on the puller. Cheers, Mike

 

[Micke S]

Thanks Mike ! The big end was completely lost due to bearing wear. So I just took a grinder and cut it and the rod pin before they were pressed out.

The engine seems to have been used with no or very little oil in the gear box. The higher two gears were severely worn, so one tooth on fifth gear was broken. The lack of oil in the gear box should not affect the rod bearing so I guess the engine has been used a long time after it began to sound bad.

So the primary gear box shaft with fixed gears (the so called Christmas Tree), a couple of gears on the output shaft, bearings etc. are now replaced. Even the splines on the kick starter and gear pedal shaft are shaved. So these axis are repaired by TIG-welding new service-ends to them after clean up.

The last picture shows how the engine will look when ready. It is a 17 hp 125 CC engine that will have some treatment to deliver about 25 hp in a 75 kg (165 lbs) moped. Nothing extreme but hopefully enough to avoid being behind.

 

[eugene13]

I haven't seen a Zundapp motorcycle since i was a kid, what year is it?

 

[Micke S]

It is a 1970 moped that will get the King Kong engine this season. Is is the stock 50cc engine on the picture but with a 80cc cylinder. The 125 CC engine is ready, just waiting for a new cylinder with head and piston.

 

[Micke S]

Here is the kick shaft that I TIG welded a new spline-section to. Just a small wart where I ended the weld that will be removed by the grinder. The other marks to the left are scars from a broken or loose drive chain.

 

[Micke S]

The engine is finally ready. It has taken a lot more time than usual due to long delivery times for parts. There has also been mishaps like getting a piston. The first one had a negative play of 0.008 mm below the piston pin and it was too narrow above the pin. The next one is a quality piston but the ring gap was only 0.04 mm instead och 0.2 mm so it was trimmed to get it right.

The tuned exhaust system is made of stainless steel and TIG-welded. It has been electro-polished by a friend to get a stock-like appearance.

 

[FOMOGO]

A 6" vise is overkill for a RF45 style mill. A 4" is more appropiate for that size mill & IMO 5" max. I have a 5" GMT vise on my PM45 & it's slightly too big. Not enough Y axis travel to make use of the 5" full capacity. Better to save your money rather than getting something too big & most importantly the weight. I take my vise of the table quite often, a 6" is still light enough for me to be carried by hand but I'm glad I have a 5". I also have a 4" vise as well. I prefer the 5" though.

But those GMT 6" Premium vises are pretty nice. I'd love to have one but don't need one on my current mill. But if you plan on upgrading to a full size knee mill in the future than the 6" will be perfect.


Here's what the 5" looks like on my mill.



I couldn't even complete this cut without my bellows & DRO scale getting in the way. Not enough Y travel & the 5" vise is not even maxed out.



Here's what a 6" vise looks like on another PM45 (gt40's)
View attachment 253544

 

[Micke S]

Wooow, that's a real pantie-wetter

 

[psychodelicdan]

Good looking bikes. Is that kick shaft a thin hollow tube?

Master of unfinished projects