it all depends on how you take care of it.. It is a rumor.. I can tell you that..
BTW all engines get loose after a few gallons.. me and another guy I raced with decided to test an os and it made 12 gallons.. no one can possibly believe that.. but I witnessed it.. mine made 9 gallons.. but I drive hard..
the bottom line is: all engines loose their pinch.. some earlier than others.. my vz-b lost it aroun 2 gallons.. but it ran great... and got better.. the vz-b is a remarkable engine... IMO