Honda Rebel transmission trouble

So today I went out for a ride, and pulled over for a minute to adjust the idle speed. While I was looking things over, I noticed that a hose had come completely off. I have no idea what this hose does, and would very much appreciate it if someone could tell me what it's for. The bike was running fine before I pulled over (actually, it was running awesome :D), it was just idling a little low and would quit when I stopped at a light. Thing was, right after I reattached the hose, the bike would not let me change gears. Bike is at the mechanic's now, who says he can repair it fairly cheaply. I just want to know what the heck happened. The spot where the hose came off is indicated with the red circle in the image below.

http://i588.photobucket.com/albums/s..._250engine.jpg

That just looks like the breather tube for the engine block (you know, so the gasses emitted from the oil etc don't foul things up)

Nahaus,
That is just a crankcase breather hose to vent to the air filter box to reduce polution so should not cause a transmission problem. Not changing gears can be a costly repair so I hope your problem is a simple one like a bent shifting fork usually caused by poor shifting technique.
Good luck.

Thanks guys, very much appreciated. I really need to get more knowledge about the basic parts on the engine for my bike! Dunno what I'm doing wrong with the shifting. I'm not hitting it hard with my foot and I always use the clutch (as opposed to a friend of mine who prefers to shift without it).

Hi again. So I had the gears replaced in the engine, about 1500 RMB all told. Drove it home and now there is this awful ticking noise coming from it. Mechanic went home for the Chinese new year sothe bike has been sitting in the garage for about a week. It's always had a little bit of valve tick but this is much worse, and gets much louder at higher revs when actually driving it. I've posted a video of it on Youku and am putting the link here. Very worried that this is engine knock. I'm very aware that a video is not the best way of showing this problem but if anyone wants to try listening I'd appreciate it.

http://v.youku.com/v_show/id_XMjQzMDgxMzI4.html

/update
Got it up to the mechanic today and he worked some kind of magic on it for free. Dude spent 3 hours on it and it now sounds great. He even tightened the exhaust pipes all around and the ticking noise has pretty much disappeared. I just wish I knew what the hell happened to it in the first place and what he did to make it go away. :cryfiddle: