use to go to Lakeside in the late 80's with my matchless,& a TA125,there was a family of yamaha TZ pilots,doug was the father,(can't remember their last name,but they were a yamaha dealer i think)anyway one of his sons raced this kitted A100,(a factory race kit from memory),geezas he could ride it,his corner speed was fairly fugging impressive,someone will remember them,worth chasing up for info,
just remembered,Doug Beak??