I can't recall when I first saw one but I remember the first one I got to play with. A lad booked one into the dyno and it produced a whole 45hp. He then took it somewhere to have it derestricted (I can't recall where). Came back only to find it still only had 45. It took a number of goes untill he cracked what was holding it back.
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If I have to take the carbs off once more...