My Puch 175 SV motor refurbishment is coming along,I have acquired a barrel a good crankshaft from Austrian ebay sites.The barrels had a bore size of 44mm ,a size which are not stocked by either RBO Stockl or Weiser but after a few months of searching i came across a German engineer/dealer who had size 44mm  Gerd Krauter and with all new bearings and seals. I was ready to insert the pistons into the barrels. Putting Puch pistons into barrels is a very precarious procedure if done in the normal manner ie barrel on top and get pistons in from underneath the barrel is heavy and very heavy if its a SGS barrel also you cant see all the piston in regards to ring position in relation to the piston pegs Result is very often broken rings !as i have found a few times.

But there is another fool proof way of getting them in place simply insert them into the barrels detached from the conrods you are doing one at a time you can see all around the piston hence no brokens rings! no stress! a bit like a hot knife through butter.

So pictures below will show the simple procedure

Pistons in place! no broken rings! no swearing! no problem!
conrods in place and attached
snap rings in place,barrel ready to be pushed down.
I am a happy man ! pistons in place no problem! not the barrel fin repair!

That,s the way to do it! the only problem is you need the motor out of the frame!