finaly got my jetting dialed in real close.i have a full big gun race system and basicaly a proflow system with nine 7/8 holes in the lid,no snorkel and all restriction cut out of lid.final jetting 155/160 main,needel in 2nd from top,25 pilot,105 choke jet.works good enough to run right along side a stock 2001 yz 250.