Man, you sound like me, ride antiques. Putting a piston in an old smoker is so easy compared to the new 4 strokes.
I ride and old YZ490, an IT200 and a RD400. Getting parts is getting tough though. Ebay is my best friend.
Oh, forgot, put a CR250R water cooled smoker on a shifter cart. That is a really bad boy there. Accelerates so hard ya better have some neck muscles to hold yer head up.
Yep, ‘80 IT250 I bought new and am ‘modding’ to this day; CR500 - ‘86 not ‘84 - referred to in the earlier comment (just got a compression release installed); ‘84 KTM 125 MX is actually the most fun rider in the stable with its ultra-light weight and case reed, and a few others like the ‘82 XL250R, 1650 miles, and Kawasaki KE100 550 miles I just re-did for my girl.
Actually, as I’m getting older along with the bikes, the 185 lb., 31 inch seat height KE is the most comfortable bike for me to ride offroad now. Stay on the gas, but stay on or above the seat even more important at our ages.
We have a kart track 3 miles away but a KT100 was all I ever drove. Yep, eBay saved searches are critical for things like mid-80s KTM water pump vanes.