reed spacers and jetting affects

ok i built me a .5in spacer for my reed cage today, i have a 96 yam blaster bone stock.. it seemed to give it a lil more pep in mid range and stretched the power band out a bit.. overall im impressed with what i got for such a easy mod.. but my question is what affect will this mod have on my jetting?. it does seem that it has a bit of bog when burping the throttle from idle now but everything else seems mucho better.. will a spacer normally lean or richen a motor?.
thanks for any advice

i did some good hard ridin on it today and checked the plug , seemed ok but im no expert plug reader.. i did notice not much smoke was coming out of the pipe after it got up to temp, dont remember whether it smoked more before though, i just bought it and only rode it a few times yet..
what size of carburater do the 250r use?. i have a couple old mikuni carbs layin around a 36mm and a smaller one not sure the size.. can you actually over carb a motor and what would happen if you did.. im in need of some carb parts for a mikuni does anybody know a good place on the net to order jets and needles and such?.