Motorcycle Repair: Sportster sneezes through the carb, air fuel mixture, dyno tuner

Question
Hi Mike

I have a 2000 883 Sportster Custom with Screamin' Eagle breather, ignition module and SE II mufflers. The previous owner had put these parts on the bike but removed the mufflers so I had to buy new ones.  I brought the bike in to my local dealer for its 5,000 mi. tune up. I explained to them that the bike was sneezing back through the carb when coming to a stop with the throttle closed and frequently when I blipped the throttle waiting for a stop light to change. It even happened once on the highway at 60mph. They said the carb had not been adjusted to compensate for the performance parts and proceeded to pop the plug on the air/fuel mixture screw to allow ajustment as well as drill out the slow jet. A mechanic test rode the bike after the service and told me the bike was running great. So I hopped on for my ride home and the bike seemed to feel more responsive at lower rpms. I rode 15 minutes on the highway at about 65 mph and when I came to a stop at after taking my exit, the bike sneezed through the carb. I called the dealership back and told them I still had the problem and had to make an appointment to bring the bike back in.
I know that carb tuning is somewhat of an art but I don't want to spend hundreds of dollars in shop time hoping they figure it out. Another local dealer recommended I take the bike to a respected dyno tuner that they use and recommend to their customers. He charges $130/hr and he told me that on average tuning sessions take about  1 1/2 hours.
Is this condition normal? Should I be worried about damaging the engine if this condition persists? Any help would be greatly appreciated.

Thanks
Rob

Answer
No the condition is not normal, but it wont hurt the bike.
First thing I would check for is an intale leak. Start the bike and let it warm up and spray a little carb cleaner around the intake. If the RPMs go up then you have a leak.
If you dont have a leak I would install a Dyna-jet kit. It has the correct jets you need. Never heard of drilling a jet instead of replacing it to the right size. the Dyna-jet kit will give you more throttle responce
Good luck and happy riding
mike