Having had a blow out (valve snapped off for some strange reason) on a rear tyre at close to 100 mph I wouldn't even consider using a plugged tyre. Had the bike wobbling and trying to chuck me off all the way to a stop. To this day I don't know how I stayed on it. Never want to experience that again. For the sake of a small expense, get a new tyre and bin the old one.
Did I write something about the Law? In the end it’s your decision how fast you ride a motorbike with a repaired tire.
British Standards for puncture repairs - Motorbike Tyres Reviews | MCN Michelin, however, is the only manufacturer that recommends that its Z rated tyres can be repaired in accordance with the previous BSAU159e.