250x Ultra - Air filter?
I purchased a 2007 250x Ultra used and have been riding it for several years. Recently, we have noticed a performance decline (capped out at 40 mph vs. 60+ previously). Looking at a number of posts, checked some key components (e.g. supercharger, plugs, impeller, etc.) and didn't find anything notable that would impact performance to that level. The supercharger is still kicking out 3/4 of the total and the engine hits 6500-7000 RPMs, both of which seem to be lower than I would expect, but didn't really take note of those levels before the performance issue.
I found a post (not related to this specific model) that suggested that if there is build up in the air filter, that could have notable performance degradation. So, I took off the hoses and did an inspection inside with a bore scope. I was a bit surprised to find that the assembly didn't have anything inside - no filter of any kind. I cannot find anything online with any parts sources that show anything but the assembly, but they still call it an air filter assembly.
Does anyone know if this is just an assembly or if there is supposed to be some type of filter inside?
Any thoughts on other things to look at regarding the loss of power?