Someone help me make my 250sx faster!!!

[Fitzy]

I have a 250sx and got beat by another 250sx that had a dude and his G-friend on it.... His bike is stoke while mine has a UNI filter and a Cobra Exaust. Someone said that the exaust is what is killing me.... Can anyone give me tips and help me out please?

[Fitzy]

Sorry I ment to spell Stock not stoke....

[puttputt]

non-stock air filter and exhaust is going to require rejetting -
( carb needs to flow more fuel to compensate for the increased
airflow from the airfilter and exhaust.)

Search the board to find out what jets other people are
running with the same filter/pipe setup. That's your best bet.

Otherwise, it's going to be guesses and plug chops, which isn't hard, but it is time consuming and uses lots of plugs.

[Black Sheep]

are you both running the same size tires?

what conditions are the trikes in?

a heavily abused trike will be slower then one with less wear and tear on it.

if you jetting is correct a pipe and filter will not make your trike faster in top speed but will give it better acceleration.

top speed is mostly determined by gear ratios. since 250sx's have shaft drive you cannot change the ration (unless you use a big red assembly if it would even work and even then it would slow you down)

[Fitzy]

The bike has been rebuilt... The engine has new rings, oneway bearing, starting gears, stator and ignition coil... My valves have been set.... I have a 130 main jet right now and it is stock... I am waiting to break the engine in a little more before I change my jet. I have 22 inch kenda vippers and my friends SX that kicks my ass has 22 wooly bugars... you can see my trike on my other post... http://www.3wheeler.org/vb/showthread.php?s=&threadid=15095

[350XXX]

check the circumference of the tires, just because they are stated to both be 22" tires, they may not measure the same and his might be a different size. usually woolly boogers are balloon tires and i believe vipers are more of a flat profile. the tire with the greater circumfernce will be the faster of the two. and running your stock jet in a motor with a pipe and filter thats just been rebuilt is NOT a good idea, your running your bike lean and can cause irreversable damage to your piston and rings without another rebuild of the topend. go ahead and change your jet out.