I just wanted to wrap up this thread with an update.
SIP was sadly back ordered on a lot of essential parts but I found Scooterworks had a replacement crank for double the price of SIP (ouch) and whatever else was missing. Couldn’t find any other US shops with parts but I’m happy with SIP and SW.
First off was taking a lot of pictures. This was totally unknown territory and I needed all the help I could get.
Motor dropped it split apart pretty easily. Since the crank was already damaged I didnt worry about being gentle with it. A few good whacks with a hammer and it fell out of the cases. Gaskets were glued in so it took a whole day with a razor blade to clean all the surfaces (I made the owner do it
).
Everything inside looked pretty good but while there I changed the shift cross, kickstart buffers, oil filter, a few o rings and gave everything a good scrub.
Reassembly was quick until I got to the timing gears/chain. The service manual I downloaded from motor scooter guide.net was helpful but I still scratched my head a few times putting everything together. Long story short, before you tear down, remove the clutch and line up the crank/ timing gear/ oil pump gears and mark where they mesh with a paint pen. Lots of variables!!!
Once that was sorted everything went together pretty straightforward and everything was torqued to spec. I checked the valves and they were too tight so adjusted them, stator in, gas on, a few Hail Marys and I kicked it over. Second kick she fired up and purred like a kitten.
Owner was stoked and is off terrorizing everyone with his stock sewing machine muffler!
I told the owner that sadly anything major that would happen with this engine would probably be the death of it. Parts are harder to come by and it wasnt a popular model in the States. Told him to save up for the 200 crate motor or buy a two stroke.
Hope this helps someone in the future.