I went on the highway in my mini 850 from 1977 and decided to give it full throttle in 4th gear, for around 30 seconds. top speed 75mph/120kmh when i drove off the highway (right after) and went to drive in the city, after 5 min my mini lost all of its power, it was like stumbling, i drove home slowly around 12 mph/20kmh. The next day i decided to clean the carb and go for a testdrive, it drives, but not like it used to, it suddenly lost a lot of power and sometimes it wont drive, just idle. I when waited 10 seconds and it drove again. What seems to be the problem? Could a compression test help?