I have a Beta EVO 200 2016 and a Beta 250 2015. I’ve recently cleaned the 200 carb and yesterday decided to clean the 250 carb. When I removed the 250 carb I found a vent pipe on top of the engine. I think this pipe has fallen off the vent on the bottom of the carb, but I’m confused as to why the 250 has a vent pipe and the 200 doesn’t have this pipe. Both carbs are the same. Should the 200 have a pipe? I believe this pipe is used to direct the over flow fuel away from the engine, but does it have an effect on the bike performance?

Nope, all the pipe does is dump overflow fuel down the back of the engine instead of the top, operationally it makes no difference.

Thanks for the confirmation, I’ll get some pipe and add it to the 200.

As misscrabstick says, the pipe on the bottom of the float bowl is just an overflow pipe to run any leakage down the back of the engine. 

However, when you fit one, make note as in your picture that you cut a little "v" cut in the pipe 50mm or so from the clip -that is to prevent syphoning .

Splatshop do the genuine Keihin vent/overflow pipes which don't harden like some plastic tubes.

Thanks, I’ll have a look on the web site.