''fuel controller''The stock CBR250R exhaust has the cat inside the muffler. The stock head pipe has a double wall design, whereas aftermarket head pipes are of a single wall design.
While a small gain in peak HP can be had with a full aftermarket exhaust system and a fuel controller (to richen the fuel/air mixture), you can also expect to sacrifice a bit of low and mid range power and throttle response with such a system.
Start by scrolling through this Performance forum, where you'll find numerous threads on fuel controllers.''fuel controller''
I was wondering what's a fuel controller and where can I buy it from?