Triumphrat

A frequently asked question about Bonnevilles/T100s is how can I modify my stock mufflers (silencers)? Here are the instructions for removing the rear baffles, drilling the remaining baffles and rejetting tips. Bill T100 initially gave me the instructions and I have added to them based on my and others experiences.

Tools needed:

1 ¼ “ metal hole saw (choose a good one)
Minimum 8” long ¼” metal drill bit
Preferred: ½ in drive drill

The rear baffle is held in place by a rear flange and an inner flange. The baffle is tack welded in two places to each of these flanges. Use the hole saw to cut through the rear flange of the rear baffle. This gives you a nice smooth cut.

Use a drift or hold an appropriate sized socket against the rear baffle tube with channel locks or vice grips and tap it sharply to break the spot welds on the front flange. Next remove the fiberglass that is around the tube/baffle with a needle nose pliers or hemostats. The fiberglass is wrapped with thin wire to hold it in place. If you can grasp the wire with needle nose pliers and break it, the fiberglass packing will come out easier in larger chunks. Removing the packing is the hardest part of the job.

When you have removed the fiberglass packing, you can see the inner flange. It is perforated with 1/8” holes. Use the long ¼” drill bit to drill five or six holes in the flange close to the baffle tube. I drilled six in the pattern of the chambers in a revolver cylinder. You are drilling it out all around to create a larger opening and allow for the baffle tube to come out. Grasp the baffle tube with pliers and pull it out. You may have to twist and turn it some to get it out. If it won’t come out, simply drill a couple of more holes. One of mine came out with six holes; the other took seven holes.

You probably don't have to rejet, but if you went up to 112 or 115 main jets the throttle response should improve. The holes in all the internal baffles are 3/4" so you are not dramatically improving the flow through the mufflers. The sound is a little deeper and about 15% louder than stock and doesn't sound like a sewing machine anymore. This is definitely worth doing if you don't want loud mufflers but can't stand the sound of the stock mufflers. You should turn your mixture screws 3 – 3 ½ turns. I turned mine out 3 ¼ turns.

In addition you can drill through the remaining baffles. I did this and it improved the sound as well as improving the flow.

To drill through the remaining baffles you will need a flashlight and a ½ or ¾ inch metal drill bit welded to a 1/2” steel rod approximately 38” long. I measured from the beginning of the front taper of the silencer to the rear of the silencer. I then applied this measurement to the 38” steel rod measuring from the tip of the bit back and marked it with fingernail polish. I did this so I would not push the bit too far and hit the taper of the silencer. I used a ½“ bit simply because I did not have an extra ¾” bit. It really doesn’t matter. It’s definitely not rocket science. If I remember correctly, there are four more baffles to drill through.

The end result is not quite as loud as TORs; but definitely cheaper and it sounds pretty good.

Jetting: For just the rear baffles removed, try 112 to 115 main jets. If all the internal baffles are drilled out with a 1/2" drill bit, use 115 to 118 main jets. For 3/4 " drilled internal baffles, try 120 main jets. Jetting recommendations are for sea level and the snorkel in place.

Submitted by CarlS

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