I did a hollow mod on my 2011 tdub. After installing a pod filter and an aftermarket pipe, I took it to the local Yamaha shop for a rejet and a valve adjustment. The mechanic decided the carb only needed an adjustment and not a rejet. I rode to work today and almost immediately experienced problems. At mid to high speed the engine was missing. When I let off the throttle and then re accelerate it misses badly. What experiences have you other hollow mod guys had. I figured a certified mechanic would do a better job than I would and therefore trusted them. I'm taking it back in tomorrow, but am already being told that it could be my modifications that are causing the problem as the bike wasn't designed to run with these mods. I'm thinking that any mods you can do can be adjusted for as I have been a long time Harley rider and all the mods I made to those bikes could be regulated so that they ran smoothly.