Good eye and yes you'r right it does only go left to right. I will add the detailed piston modification later in the thread, it is very simple and only takes a few minutes.Last photo in post #42 - upon mounting the engine, I think the rear lower mounting bolt (with the long spacer) goes in left-to-right. I've read that the head of the bolt is slightly shorter to avoid interference with the chain. Mine was forgotten (by me) and is in the box of parts still to go on. BTW, what luck to be able to go with first over! Check on the Banshee pistons however - I've seen something about a minor mod that is needed when going in RD jugs.
Everything in mine was tight, but the bike is SUPER low mileage. I checked everything 10 times, I was driving my wife nuts with constant dwelling and considering options. Finally she said, "You know if its good or not, so fix what you need to a move on." Haha I replaced the outers because one of them looked at me funny and I could hear noise in the other with a stethoscope...was more or less just curious if I could.Hope it works well. I went the spendy way and sent mine off to Lyn Garland for a full rebuild (all bearings, seals, and rods for the crank). But, I could feel roughness in the right outside and right center bearings pkus the rods were right at the side-to-side limit so it had to be done.