I have a 2013 S40. Was wondering if it has a rev limiter. I was out a few weeks ago and really wanted to see what the bike could do. I think I ran the bike up a little to hard because now it seems a little noiser and has a little more vibration when running around 50 and above.

How many miles on it?
Dunno if it has a limiter.
I wouldn't run it all the way out in a gear other than high gear.
Shift up when you get to the end of the good pulling part of the acceleration.

Have you checked the valves? That's a 5000 mile thing.
The adjusters look like a pencil with the lead mashed blunt. As they smash into things they mushroom and work harden, eventually not needing adjusted so often.

It's possible that you rattled some crap loose in the exhaust.
Listen for Where the noise is coming from.

Is there rust obvious on or in the exhaust?
If you gas it, can you see anything come out of the exhaust besides exhaust?
Is it backfiring more ?

Is the pipe blue near the head?

Uturn, I wouldn't worry about it too much. I think you are paranoid, because the muffler changed internally causing a different sound. I KNOW my bike sometimes vibrates more at some times than others, even on the same ride after gassing up or taking a break. Never figured it out. And my muffler spit the baffles out at 8000 miles (A 2001)

I recommend an oil change with or without a filter (unless it's time anyway) and use Rotella T
regular dino oil 15w45. It will reduce engine noise more than synthetic. It will take you 20 minutes and you will hear the difference. keep posting and figure it out before you spend a lot of time and money. Be patient.

Yeah, what he said.

There's a very old thread around here about this very "problem". The consensus was that there is not an electronic governor built into the ignition system. Chances are the head is not flowing well above ~6500 rpms so the engine speed stops climbing. Have you seen the horrible exhaust port?  

Good point, Kenny.