That is a good shot of the modified 125, Dad, and me I guess. That 125 has a high dome piston from some lot more late model multi-cylinder honda street bike, which fits rod and stroke just right. and we didn't have to do a lot of machining on the cylinder, more or less just bore it a little, from (my) memory of when gathering up the parts to do this, quite a while back I might add.
FWIW, there was talk early on in this project about a 175/or so kit, but I guess there was a lot of trick machining to be done on original cylinder/head all that, or find bigger bore cylinder/head and adopt it to this bike. As you can see, we'd opted to just do this simpler mod, for a "rider" bike. Very happy with how it runs, more than a 125... If you like 4 strokes.
Dad thinks he got the weight down, removing stuff that is not essential (some was done by previous owner, from MWTA. so giving credit). We changed the rake on the front. BTW, It still has a kickstand, but you can see much other non essentails are gone. It now weighs to something like 170 (he had it wrote down but we cant find it, so figure +- 5 pounds, simply because I didn't believe him when he said he thought was in the 160+ lbs range...) LOL trying to keep my credibility if I post that, you know...
I usually forget to smile, then regret the shot, this time I might have overdone the smile though... It was windy as hell, and he never said "cheese" lol... Sigh.