Thank you, and thanks for the info.My guess would be that the right side is getting a bit more heat than the left side because of the pipe. The cooler side condenses more oil on the valve guillotine than the hotter side. I have not noticed that on my 800 SKS, both my valves are about the same when I pulled them to clean them.
If it were carbed, you may be able to adjust jetting on the hot side to add a bit more fuel to cool things down, but with EFI.. .no chance to do that. The oil under the diaphragm would indicate both sides are getting adequate oil, as the oil under there is coming from the exhaust gas that condenses on the undersides of the bellows.
Welcome to the forum!