07-05-12, 08:55 PM
it is a bit more complex than that,it works by sending the pulse back to the exhaust port which stops the incomming mixture from going into the exhaust,an exhaust can only be designed to work for a short rev range efficiently.but the exup only works on the mk1 fazer in this way,on the later fazer all it really does is to quiten the exhaust,it is the same as the valves on other make bikes