I have a 2001 300 ex with a T-4 pro-circiut pipe,K&N, airbox mod, I am running a 168 main jet and it seems fine. I do not know if it is stock bore and stock cam. With stock cam/bore what is about the largest size main jet to run good.

Also I have baja T-9,s and 22" hole shots, If I mostly ride woods and really don't care about top end what teeth conf is best.

Thanks in advance for your help.

 

You say it runs fine I would leave it alone but, a 168 main sounds to big to me. Check your plug. Jets are cheap play around withem.

 

168 wow i have a full pipe k a n and a only 125 main hmmmm..