It's not a very good pic, but do you see the spigot on the top of the valve cover, under the word camshaft(Diagonally down and to the right)? That's one of the two air pumps that make up the KLEEN system, the other is on the right side of the valve cover. You can just see the end of the spigot in the pic. This is what the block off plates replace......
The little valve between the two plates is called the Air Suction Valve. It's job is to take clean air from the airbox, and with the help of the reed valves under the plates, pump it into the exhaust stream just past the exhaust valves. Here's a better pic of the system in place on the bike, and a pic of the reed plates:
By pumping fresh air into the (stock) ehaust, the Catalyzer can burn any unused fuel and lower the emissions of the bike. With an aftermarket exhaust that doesn't have a cat(none do) when you inject that same fresh air, the fuel burns in the pipe and results in a backfire, and/or nice blue flames coming out of the pipe. The "reed block off plates" from Rob Muzzy and others get rid of that Air suction valve, and prevent fresh air from getting pushed into the exhaust flow. This helps to reduce the 'after burning' of unused fuel, or 'backfiring'
It's pretty simple to install the block off plates. You'll have to remove the tank and airbox, then the suction valve and stock plates. Install the block offs, and while you're in there you might as well get rid of the evap(charcoal) canister under the right upper fairing and route the tank vent to the outside world. there are some articles on the subject with good pics and a detailed explanation of the process so I won't go through it here. I'll try and find you some good links a little later, but it really is pretty easy, but mind you, in your area it may also be 'illegal' for use on the street. But then again, so is your pipe But if you don't have to pass an emissions test, who's to know?
Cool, thanks. I've heard that you can also ditch this with a couple pieces of PVC...is that thing an actual air pump or just an opening?
Only got a TwoBros slipon but yeah, it's probably illegal. I don't think there's any emissions testing in Maryland, though.
I didn't see any evap cannister when I had the tank off...there were two hoses and a wire coming out of the bottom of the tank (fuel intake, vent, and fuel pump wiring)...the vent hose just went straight down and dumped out on the street.