I read about this modification on the spirit forum at Delphi. Seemed to be a good way to get some thunder without spending $400 bucks. Here's what I did.

Click on images for larger view.

This mod was very fast and easy to perform. It only took about 30 minutes from the time I rolled out the drop cord and got the few tools I needed ready to go. I suggest you use a 1/2" electric drill since it has more torque. 

The picture below just shows how the hole saw fits into the rear of the pipe. Just attach a 2 1/4" hole saw to your drill and insert it into the end of the pipe. Adjust the pressure you apply while drilling so that you don't overload your drill and cause it to overheat. If you use a standard 3/8" electric drill the procedure may take longer to complete. I did not use any type of oil on the saw, I figured it would only sling onto the bike.

This next image shows that you will have to drill thru 2 pieces of metal before you can remove the insert. You will feel the saw give as it cuts thru the first layer, just keep going until you feel it go thru the second as well. Don't worry about hitting anything you shouldn't because as you will see later there is nothing else in the pipe within reach of the saw. Once you cut thru the second layer you should be able to wiggle the insert with a pair of pliers. 

Just wiggle the pliers up and down and side to side while pulling to completely remove the insert from the pipe.

The next image shows the final product. I didn't feel it was necessary to sand or paint the inside of the pipe.

That's all there is to it. Fire up the engine and enjoy the thunder.  In my opinion this will make your bike as loud as any I have heard on the street. It really sounds great while accelerating. 

Drilling out the plugs to adjust the Pilot Screws.

E-mail me with any questions at shadowrider2001@hotmail.com