jetting the carb

[QuAdEr 317]

i have a 250x with sum work lik piston n cam n i just put a dmc alien pipe on do i HAVE to jet the carb and if so any recomendations on jetting

[cals400ex]

jetting depends on weather and elevation. the colder the weather and the lower the elevation, the larger jets you need to use. i don't know the factory size jets on a 250x. you will want to go a couple sizes larger than stock on the mainjet. you will probally want to go one size bigger on the pilot jet. you may need to move the clip on the needle down one position too. jetting is trial and error. and yes, definately rejet your bike.