2017 txt gearbox noise

[SamAs]

Hi all, Ive recently got a 2017 txt racing 300 and it’s making a noise in the gearbox. There is a ticking noise that im assuming is the chain as it does this in time with the master link. But once I shift into 4th gear the box starts to whine like crazy. I know theyre straight cut gears but it sounds like a race car, it’s almost louder than the engine. I’ve been told that it’s a case of possibly bearings or something in the box but seen on an older post on here that the whine is “somewhat normal”

im just trying to figure out if I need to take the engine out or not as I’ve never done it before and dont want to do it if I don’t have to. But I want to do as much as I can myself to save money as the bike cost me a lot. 
 

thanks in advance for any help, I might end up taking it out soon anyway it’s just a bit daunting