Restricted???

[Silverlegacy]

Has it had an oil change recently ie with car oil?......just curious if it could be the clutch slipping at higher revs if it has the wrong oil in..........or was it running well before & then started doing it without any changes ie services?

Its had an oil and oil filter change about 5 months ago at a motorcycle dealer.
Its been running like it pretty much since ive owned it, I left it at the garage and the mechanic took it out and said its fine and nothing wrong with it mechanically? so would like to think that hes given me the right advice, rather than making up a list of things that could be wrong just to make money off me.


I will give the air filter thing a try, i did check it the other day and seemed clean enough, but my clean and other peoples clean might be two different things.
Dont have any other biker friends local who could at least take it out and give me there opinion and trying to find a big enough section of road to at least try and push bike a little