put a k+n air fliter on but need to re-jet

put a new k+n air filter on my jonway 125 and now it bogs down when i rev. re-jetted the carb to a 130 but it seems worse! amy idea what stock size is in these and what id be best starting with?? oh the stock jet doesnt have anything written on the side either so i havent a clue what size it is. cheers

 

Put the std airbox on, it work's perfect!

 

Ok, so you know when you change the filter you have to re-jet to compensate for the excess of air being drawn in to the carb and cylinder, so you trawl the manufacturers site to get the standard main jet size, then call donotlink or the like and order several jet packs of various sizes and start to play until you get the right response.
Taking a quick look at the site tells me that the main jet is anything between 80 and 140, so if 140 is the top size they supply then most likely you'll need higher to accommodate the open filter.
Like i said, buy several packs and PLAY