Bad News - Rough sound at low RPM and lack of low end power

[BluSkyLightning]

A new development in the short history of my Seca, a noise has developed after I got on it a little bit. I did a little bit of a launch in first, and got it to about 35mph, nothing crazy but I did accelerate really quick. Right after that, the bike started to make a noise while the rpms were low. It seems to have a lack of power under 2k, but seems alright once past that mark. I checked the oil level and it was low, and have filled it with Resnol oil in 15w-40 as that was all that I could find. It does seem to have lightened up a little bit, but the noise is still there, and so is the lack of power.

Also, it seems that the noise is coming from the transmission? The motor itself isn't making any scary noises, it seems to be coming from the transmission area. It is getting kind of dark out, and can take a video of the noise tomorrow, but this just happened.

Any ideas or things that I should check first? Its hard to explain a lack of power when the motor itself seems to sound ok. I also smell a little bit of gas it seems like, could be oil but there is no smoke from the exhaust or obvious leak, the motor looks clean.