I don't recall them loading up bad. If they did it was due to some jetting problem.
I remember buying a new '75 TS 125 with my paper route money and stripping off all the lights so it looked cool. I then dove into the motor to see how much more power I could get out of it. I was 15 at the time and really had no idea what I was doing. As soon as I heard about the latest gimmick to coax power out, I tried it. That little bike was very abused in due to my tinkering. The big buzz word at the time was to "change the jetting". OK, cool, so I changed the jetting...and promptly seized the thing. From that point on (for a few years at least) I didn't mess with the jetting. I guess my point is that through all of my tinkering, I never had problems with it loading up so the jetting must have been pretty good to start with.
Sorry for rambling ;)