Had the upper of of an f4. after i put it back on, the bike runs like crap. what could i have forgot to put back on? it idles, and runs good. but it falls flat on its face around 3k rpm. any ideas?

i saw a hose running under the headlight. could i have kinked it to make this happen? i'm lost here. any help would be great.

 

sounds like you may have disconnected one of the main vacum lines dude. right up front in that area are a few big ones (about 1/2" or so) that need connction to the airbox and to eachother. it will barely run with out them... you should hear it too. check for those hoses first.

 

yep, that was the one. all better now. thanks..................