I just got done putting one of these back together crossing parts around from three different motors. While I found out all three motors were different in some ways here is what I got for you.
http://i137.photobucket.com/albums/q208/foureasy/DSC01079.jpg
http://motorbicycling.com/f13/hybrid-chinese-motors-performance-tuning-14204-13.html
This image location shows what Foursay has done. The photo on the right shows basically what our crank shaft balance was left at. We checked over three cranks finding one we would not have to grind.
I did not mean to side track you with that it is just food for thought. Our motor proved to be smoother than the other cranks we discarded. It was a smooth motor. The crank we used came from a rusted out Craigslist buy... Just used what we had.
We dry fitted the case observing side to side play on our crank . Believe it or not a really thick crank shell gasket left us some slop at the crank [side to side play]
We made our own gasket a thinner one that took up the play perfect. We used
http://www.permatex.com/products/au...mum_temperature_rtv_silicone_gasket_maker.htm and have used this stuff on practically everything love the stuff!
Used a very thin layer on our crank case gasket was perfect [both sides of the gasket] Also used it on the other gaskets as well.
Now a bit of voodoo we put into our motor was..
On the Out put shaft bearings I took the inner seals out of the bearings facing the big clutch spring. My thoughts are here that with a well placed weep hole drilled into the bottom of the crack half casing over packing these bearings will not be a prob as any built up pressure will push the grease out of that weep hole. Now where the post that holds the clutch cable housing I take that post off later and I fill the whole cavity with bearing grease. There fore re-greasing the the bearings without major engine dis-assembly could be avoided.
The weep hole is my scape goat from building too much pressure and getting grease beyond the out side bearing seals and into the clutch. [important] Put the weep hole down low so water cannot get in also about a 1/4 inch or slightly larger hole is what we did.
My thoughts here are simply wipe away any weeping grease off the hole as it goes. I realize this is a controversial suggestion so let the fur fly!
If you are familiar with bearing buddies on trailer axles then you know it is easy to over pack them.
As for the clutch bearing there are three holes on the back side that you can gently pump and work grease into, did that as well.
Now we found when we went back together with the case halves was that after tightening up the halves. we took a large socket and hammer [gentle love taps] to the spots where the crank and out put shafts come through the casing. This proved to further settle the casing shut together better, as evidence showed our case bolts were loose again.
Used a hint of blue lock tight on our case bolts as well. As for how tight we got them we got them pretty tight. [Was hoping not to ever touch it again lol.]
Head gasket about 14 foot pounds is where we put it and looking at the size of the rest of the hardware you get the idea.