Exhaust Butterfly Valve

Hi PDeak, and welcome in no idea I'm afraid

 

Hi mate and welcome

 

Welcome!
Mabe this link will help explain. It's a tad technical but covers most of it

https://www.bennetts.co.uk/bikesocial/news-and-views/features/bikes/how-does-an-exhaust-work

 

Hi, originally i thought that disconecting the cables would keep the valve open, but it doesn't, it keeps the valve almost closed. So then i opened the valve all the way open by some twisting and bending of metal. The diffrence was crap low rpm power, was horrible, so, i put the cables back on, and hey presto, power came back, more torque and a smoother running engine. When the valve was almost always closed it felt better than always open, but fell on its feet because the gases couldn`t escape after 5,500 rpm, making it feel like shite, had loads of torque because of the back pressure/SCAVENGING effect down low but high rpm failed. That valve is there for a very good reason, so personally i would leave it well alone or buy the akra slip on with the valve. In England the slip on or muffler is called a silencer for a reason, to serve the purpose of silencing noise, not emissions, as many are led to believe. The CAT, silencer and valve all have different applications, that work in perfect harmony in stock form, for stock fueling.