Motorcycle Repair: xj 600

Question
hi I have a xj600 Yamaha I was riding down the motorway I would lose power then it would come back and it kept doing this I felt like a kangerroo any ideas please

Answer
Tony, this could be a simple problem just try to narrow it dow. It sounds like a fuel problem. Its possible the carbs are starving for fuel. A fuel filter could be plugging up or the fuel valve on the bottom of the tank is restricted. Or you may even have a vapor lock situation where the tank vent is plugged up. The engine runs out of fuel and loses power then surges when the fuel catches up.