Those reeds should be closed???? ... In essence they are a one way valve to stop your lovely fuel mixture being pushed back out of the carb with aggressive inlet port timing / overlap, robbing you of your bottom end, whilst making the bike run leaner, (and oilier
As a test you could try and turn them around, however from the sounds of things they are poked and even that would be a temporary reprieve, as they won't last. Replace them!
Back to your plug tho';
You say you're currently using an NGK BR9ES, yet the recommended plug for your bike is a BPR8ES
, (note the additional P in the part no.
), which is a PROJECTED NOSE PLUG, and one range HOTTER than what you have in!!! ... try one, and as I previosly recommended, if this improves the problem, but doesn't cure it, the go to a BRP7ES, (even hotter plug)
Check the plugs porcelain colour after changing. If it's brown stay where you are as plugs go ... If it's white, and/or the motor shows any sign of pinging / detonation, then go colder. If it's black, and/or oily / fouled, then go hotter
As to your powervalve ... You should be servicing, (cleaning
), your power valve, along with decoking your pipe on a fairly regular basis anyway!