I just installed stage 2 Hot Cams(E/I) on my 06 DRZ 400S: The bikes setup: Evo X Full Exhaust Stock Carb with 147.5 MJ/25 PJ Dynojet needle and spring from Stage 1 S kit 3X3 opening with Uni air filter 3 Turns out on the Fuel/Mix screw After installing the cams, the bike started up fine. The bike idled okay. When riding, transitioning from the mid to the top range the bike studders/coughs, then takes off. It seems to run good as long as its accelerating, but when cruising then hitting the throttle.. studder...then goes. I made the ride with the cork in the exhaust. I wonder if the exhaust restriction of the silencer is too much for the exhaust Hot Cam?