The short answer is you're right-especially if we're talking about the sort of plug that is usually stuffed into a nail hole at the side of the road. In that case, we would proceed directly to the nearest repair shop at a conservative rate of speed and have a new tire installed. Life is too short to take that kind of chance, and taking it is a terrific way to shorten it. With a plug/patch combination, applied from inside the tire by someone who's done it before, there's some theoretical wiggle room-especially since we're talking CB450T and not CBR1000RR. If your hamster is on dialysis, the rent is due and you promise to keep it under 80 mph until there's room in the budget for fresh rubber, well OK. We still wouldn't, though.