I have been fiddling with these engines for about three years now. The one thing they have in common is there is nothing but there looks that is common. I have a spare cylinder that I spent a few hours porting, yea I got a little carried away. So I next needed a lower end assembly to run it on, so I ordered one from Revolution. It arrived looking good, I was stoked and started to assemble the motor, and to my surprise the piston was about 1/4 of an inch from the top at TDC and hit the crank at the bottom! Now what the heck. I went home and got a new piston and cylinder I ordered from Kings a year ago, took it to the shop and lo and behold, it works. I set the pistons next to each other and what do you think, the wrist pins are in a different location on each, yes the one I needed had a lower pin location. I knew the crank for the 48cc was different but I never heard anything about the 55 and up. Also there is a two piece flywheel and a one piece, with and without balancing holes. One crank with 202Z bearings and one with 203's. I like the heads with the larger fins, but the one I have is not relieved for the larger piston, but it was on a 70! but I tried to install it on this 70 and the piston was hitting, so I used the head with the smaller fins and the relief. These engines need all the cooling they can get, they need a lot larger cooling fins, but this will have to do. I just wanted to let everyone know that you need to keep and eye out if you start ordering parts to do a rebuild, maybe you should just order all of them. Oh well you might as well get them all put together. Oh it is probably easier to just order a new kit. Have fun Dave
PS: I will let you know how the port engine runs. I can get my thumb down the intake. That's a compression release in the head.
PS: I will let you know how the port engine runs. I can get my thumb down the intake. That's a compression release in the head.
