250x -400ex carb will it work

[jaggers]

hello i fellow riders, i have a 87 250x, i was thinking of modifying the engine. ive got a pipe filter, I was wondering if a 400ex carb would work on my machine.. if not what would. money is a issue so im looking to find a oem carb on ebay. right now my engine is stock. i was thinking of running 12.1 compression, is it worth going big bore? i know it will have more ***, is thier better ways to make power for less? :)

[Out_Sider]

big bore is DEFINATLY the way to go, but if your on a budjet i'd say just go about .080 over with a high comp piston. Get a good Cam, and a port/polish job would definatly help out also. Yes a 400ex carb will fit, but i'd recommend buyin a 350x airboot. it makes it SO much easier to put the carb in place. i had to boil my stock airboot for it to be big enough to fit it. but with a piston/cam/carb/airbox mods..u should have a pretty good li 250x there. ;) . and u can also custom make some Aluminum airscoops for it to help keep it a lil cooler on long/hard rides. Will u be racing any, or is the just a trail machine? Hope i helped some, if u have any questions feel free to PM me. ;)

[jaggers]

i was thinking of doing some mx racing. when you put your 400ex carb on did you have to do some extensive jetting? What is the highest compression you would go? I have heard that titanium rockers are important. ok ill just hit you with one more, what about the valves are the stock size to small, or do they flo pretty good with a port job?

[ghak99]

You will notice a pretty big difference if you go with a 400ex carb, cam, high compression piston, and high performance valve springs.

If you got with the 400ex carb, you should pickk up a 350x air boot so it fits better and flows right.

If you do go with an aftermarket cam I would go with hardened rockers also. Personally I would save your cash until you can tear it down and do everything right, Cam/carb/piston/rockers/springs/port&polish. It will save you time and money in the long run.

How high you want to go depends on if you want to run race fuel or not. If you go 12:1 you will need to run better fuel then you can get out of the pump.

Just my 2 cents!