81 250r carb upgrade

[robb]

i would like to purchase a bigger carb for my bike and would like to know what fits, if i bought a 85 250r carb would i need the intake boot and box.
has anybody done this to there 81 250r.

[81Rmachine]

Actually I have an 81 and swapped out the old (microscopic!) 27mm carb for a 36mm flatslide Keihin. I was curious if it was too big but 2- strokes dont really loose power with too big of a carb like four strokes do and besides mine already had reeds, boost bottle, and high compression so it needed all the help it could get on the intake side. I bought it off Ebay for 80 bucks including shipping. It made a night and day difference and surprisingly didn't sacrafice any starting or bottom end throttle response whatsoever everything is better. No you dont have to worry about your intake boot the 27mm actually has a reduceron the spigot so that it fits. This intake boot is the same one used from 81-86 alls you do is remove that and the bigger carb slides right in. As far as your airbox goes the Horn of the carb will be way too big about a 1/2 inch bigger. If you want to make it work and grab some power doing it I'd go with a Uni Pod filter absolutely no airbox restrictions. I bought one from Dennis Kirk for 17 bucks Id recommend a 2 1/2" inch dia. 4" long angled filter. The only other thing is your throttle You'll have to do what I did buy a 85 or 86 250r or 350x throttle and cable due to the increased throttle travel. Do this and you should be set. I paid about $125 bucks to do the complete swap Good Luck