honda x8rs making funny noises and trying to cut out ?

[firefox]

My friends honda 50cc makes a weid noise when going 35 ish, erm.... neeeeeeh splut neeeeeeeeh splut, get the picture ?. Any ways do you know what could be causing this. I saw one of these get a black box removed off the top of the air filter but im not sure so dont want to do nothing to it until i get some info.

thanks in advance

[phantomtek]

My guess is you are inbalancing the air/fuel mixture.

Doing this:

[firefox]

we havent removed the black box so any tips what could be causing it ?, what is teh black box for.

[phantomtek]

As far as I know it regulates air intake so if you take it off to much air will get in, unbalance the mixture and cause it to gurgle, bog down or stall. What have you done to the ped slightly before and since it started?

[firefox]

nothing i oiled his airfilter seems to have done the trick, oil filter i think there called. :\ when you remove the black box it dosent require to suck air in normaly. so basically no throttle its juston full all the time. was funny at the time we started it without the stand.