Baron Too Nasty Baffles
The internal diameter of the exhaust pipe is 2". I tried to get a number of muffler shops to take a 1 foot long 1.5" exhaust pipe and expand it to 2" at both ends; however, they found the size difference was too large and the end would split before the pipe was expanded to 2". (They were going to charge $35-45 CAN for two of these)
Undaunted, I went to Canadian Tire and picked up 18" lengths of 1.5" exhaust pipe ($8) and two 2" to 1.5" reducers. I welded the reducers onto the ends of the exhaust pipe so that the total length of this new baffle was about 12" for the short pip and about 16" for the long pipe. I then drilled 1/8" holes in the pipe; 8 around the circumference, and about 9 rows along the length for the short and 15 for the long. (For now, ignore the 'extra' piece of metal to the left of the upper pipe)
As the reducers were not quite 2", I wrapped the ends with metal tape. The top pipe shows some metal tape in the middle of the pipe, it was later removed.
First Setup: I put the baffles in the pipes and did not find much difference that stock.
Second Setup: I wrapped fiberglass, about 1" uncompressed around the holes and held it in place with metal bug screen (the kind you use for windows). This setup made the exhaust quiet but I found the tone too muffled and the low sound distinct sound had disappeared.
Third Setup: I took a 1.5" washer with no hole and welded it inside the pipe, halfway from each end so that it blocked the exhaust gases from directly exiting through the baffles. In the pic below, the red line shows the 'washer' and the blue line shows how the exhaust gases are deflected. For the longer pipe, I cut a horizontal slot in the middle of the pipe, inserted the 'washer' and welded. For the shorter pipe I took the easy way out and cut the pipe in half, welded the 'washer' to one end and then welded the cut end back on. This setup quieted the exhaust but the low tones were missing. One must remember that the larger the internal diameter of the pipe, the more bass is produced. As I was going from a 2" to a 1.5" diameter I expected to lose some of the lower bass tones.
Fourth Setup: To recover some of the lost bass tone, I figured I could either make the baffle diameter larger (1 5/8") or make the exit diameter larger. I found by moving the baffles towards the front of the pipes I could recover a lot of the lower tone; however, I did not want to drill holes in the front of the pipes! I therefore welded some flat bar stock to the end of the pipe (on the left of the top pipe in the first pic), long enough so that when inserted into the pipe I could still put the tips on (See pic below). The bar also allows me to easily remove the baffle.
This setup did the trick. The pipes were quieter but with most of the bass tones retained. The unbaffled Nasties have a loud bassy thump to them; this was now gone.
Two things happened on my test ride. I had a rattling sound from the pipes and the bike began to choke when accelerating. In the first case, the flat bar was rattling inside the pipe. I resolved this by putting an arc in the flat bar (bending it slightly) so that it forced itself against the inside of the pipe. In the second case, the metal tape on the front of the pipe started to come off and block up the holes in the baffle which resulted in the bike dying every time I tried to give it any gas. I removed the tape on the front and filled in the face of the baffle with weld and ground the weld until the baffle fit snug into the pipe.
Upon installing these restrictive baffles the bike was running very rich. I have a Nemesis manifold and BAK. The carb was setup with a 170 main, #40 pilot, the clip at 4.5 and the PMS at about 1.5. I now have it setup with a #35 pilot and the PMS at about 2.
In additional to quieting the pipes, I find the power on the bottom end has returned.