I can tell you first hand, my brother is a big fella. Last time he rode my '69 he was pushing 400 and his girlfriend is somewhere around 300 or more. It pulled them around just fine. it lugged a some, but once it got going, it ran like it was just me or my kid sister on it. As long as your not abusive, it can pull quite a bit. I don't let my brother ride it anymore though. We had a bit of falling out.

1969 CT90K1
1975 CT90K6

San Bernardino, CA, USA