Twentypercent

That’s exactly what I did, just put the blanking plate on, removed the section of hose from the bottom of the reed valve assembly and just left the valve in place to do its thing. Voila, much quieter. I think at the time I was keeping it reversible, but next time I have the tank off, I’ll try to remember to whip off the whole valve assembly. I reckon if I tape up the connector and blank off the air box, it’ll be fine. No point keeping the AIS without having a cat in the exhaust.

If the popping and banging on decel gets annoying, Off the Road do little blanking plates so you can delete the AIS completely. They just bolt on to the front of the head, easy job. Made a huge difference to my battered old R.