I've had my 06 KLX 250S for 2 weeks now. I have you guys to thank for helping me with the decision of which bike to buy. I was leaning towards the DRZ 400S..But after reading this forum..I changed my mind. It was a good decision. I love this bike. There is nothing like being able to head off the pavement and have some fun in the dirt! I've yet to do any mods, but if I drill out the exhaust baffle, will I have to re-jet? Thanks again for an awesome forum.

 

Welcome and congrats [8D]

 

Congrats on the purchase!

Almost any change to the intake or exhaust that results in increased or decreased airflow will require you to re-jet the carbs. Sometimes the change is small enough that it's not nessesary... but stock, the bike is already very lean to meet emissions.

FOr more info, read some older posts. This topic has been well discussed.