Re: Loss of power

What is the model and year of the bike? If it runs OK at lower speeds, put about 1/2 can of SeaFoam in the tank and run it through the system. You may have to do it twice, but it will clean most of the gunk out of the carbs. When you try to push it past 55, what does it do? Does it spit and/or backfire? You might look for a plugged fuel cap or carb vent or you could have an air leak in the carb diaphrams assuming the carbs are Hitachi's.