I have a 2006 Yamaha Majesty, 400cc scooter that I've had for about 10 years. I never had any problems with it before. I'm experienced loss of power. Top speed is only 50 mph on full throttle. Some things have been ruled out. Will discuss privately.
Please reply ONLY IF you're confident that you can diagnose the problem and fix it. You'll also need experience taking off the plastic parts without breaking the connections. I can get it to you if I can avoid highways. I'm in Bethlehem, near Wegman's.