Removing Rear Baffles From Stock Pipes; Applies to Bonneville/T100

CarlS

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http://s15.zetaboards.com/Triumph_Motorbike_Di/topic/72209/1/

New riders frequently want a little more sound and don't care for the "sewing machine" sound of the stock pipes. Removing the rear baffles and drilling through the remaining baffles is a cheap way to get better sound cheaply. One need not remove the silencers from the bike to do this modification.

I want to credit BillT100, NTBF, for giving me these instructions and guidance.


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.
 
<img src="https://www.triumphtalk.com/index.php?action=dlattach;attach=111;type=avatar" alt="" class="avatar" border="0"> Posted by gumpt1oo March 30, 2009 at 02:35:03 PM » in this thread:

https://www.triumphtalk.com/index.php?topic=4860.new#new

I did the bafflectomy on my 2005 T100, and the baffles were slightly different to the ones described in the link.<br>I  started with a 1 1/8" hole saw and cut through the rear flange.

This is where the baffles are different. I did not need to hit the baffle to break the welds on the front flange as the baffle moved back and forth straight away.

I removed the fiberglass and found that the front flange was welded to the baffle tube but not to the inside of the silencer. So I pulled the baffle out as far as the front flange would allow, gripped it with vice grips and then used a hammer to break the welds between the baffle and front flange. This then leaves the front flange floating about in the silencer. I then used a large flat blade screwdriver to bend the front flange out of shape enough to fish it out the silencer.

Here is a couple of pics of the baffle removed.

<img src="http://i234.photobucket.com/albums/ee16/mezzunited/ebay011.jpg" alt="" class="bbc_img" width="600" height="800">

<img src="http://i234.photobucket.com/albums/ee16/mezzunited/ebay010.jpg" alt="" class="bbc_img">

To drill through the 4 baffle plates I ground a point onto a 5/16" steel bar and knocked it through all 4 baffles, I then welded a 7/8" hole saw to the steel bar and drilled through all the baffles. From memory I think I had 120 main jets in after the bafflectomy.

<img src="http://i234.photobucket.com/albums/ee16/mezzunited/ebay015.jpg" alt="" class="bbc_img"><br><br><img src="http://i234.photobucket.com/albums/ee16/mezzunited/ebay014.jpg" alt="" class="bbc_img">
 
Great instructions thanks Carl :y18:
 
Hi guys, great post. One question, is there anything to do differently with an EFI version, like mine? Mapping?

Thanks!
 
Gump is correct. In 2005 the internal construction changed slightly.

Gabbydad, I do not know the answer to your question as I do not have any EFI bikes. The carbureted Bonneville family was tuned very lean from the factory to meet various emission standards. They needed to be rejetted from the get go without any exhaust or intake mods. My guess is that EFI models are on the lean side also for the same reasons. EFI models are designed to adjust for some variations. My guess is that the EFI will compensate for that relatively minor change. However, I will try to get you a definitive answer. I have a friend who is a Triumph mechanic; I will contact him and post back.
 
Hey Carl,
Haven't talked in a while. How's Mae Lyne doing? Haven't seen anything on the site. Hope all is well.
Winter has set in here in MS and my '04 Bonnie is in the garage for now. I took all of your advice last time on the bafflectomy. Instead of an extended rod with a hole bit for the remaining inner baffles though, I used a 3/4" steel punch rod and it did a great job. Sound is much better. I had already removed the air inj. system, put in a UNI filter, removed the snorkle, put in a bell mouth polaris, and rejeted the main to 120- did not rejet the pilot. Also put in one shim on the needles.

Question now is: I'm thinking about doing the "do it yourself" removoval of the air box by cutting it down with a dremel (will save around $250 for a kit). I got nice instructions from Tommy Turbo on the RAT forum with good pics. My question is twofold. Is the removal (the do it yourself) going to actually boost the hp. I've read conflicting forums, but most seemed to indicate you would gain 5-8 hp with the removal and installation of cone filters. I hope my gutting my stock pipes will give enough air flow. Second question: if I do the cutting or purchase a kit and do it correctly, will this still work if down the road I do the big bore?

A lot to digest, my guru, but I would appreciate your opinion.

Ronnie in MS

P.S. I'm trying to ride in the rain, but still a bit wimpy about it.
 
Hi, Ronnie. Good to hear from you. Mae Lyne is doing well. Her recovery is progressing; but it will be a couple of months before she can ride. She is driving again. Thanks for asking.

Sounds like a great job on the bafflectomy. Congratulations. I tried a shim on my needles and it was just night right; I took it off. I also have a Uni filter. Have you dynoed with an exhaust sniffer? The air/fuel ratio and the torque curve will tell you a lot. Regarding the airbox, like you, I have heard both sides of the story. I suspect you will gain a little HP if you tune your bike right. I think it will be more like four to six HP. You have already gone to a Uni filter and removed the snorkel which gave you and increase. Therefore, your gains from the airbox removal will be a little less. The disadvantage to me would be water because I do ride in the rain.That is what has kept me from trying it. If you do try it, you will need free flowing pipes to realize the gain. The modified stock pipes are not going to do it. The air box removal will definitely work with a big bore.

Don't forget that the airbox is part of your rear fender and the battery box.
 
Hi guys, great post. One question, is there anything to do differently with an EFI version, like mine? Mapping?

Thanks!

I have performed a Bafalectomy on my 2012 scrambler , she sounds great and performs even better..........i did one of those 20 min tunes and thats it :y6:
 
Yeah you always need to do the tune to get the best out of it
 
im impressed, i saved $ 1200.00 on aftermarkets.............:y92:
 
That is a great saving for sure
 
I'm ressurrecting this old thread. I'm thinking about doing a baffelectomy on my 2006 T100. I've heard that starting in 2006, the stock pipes are much more difficult to remove the baffles. Sounds like due to more welding of the internal pipe requiring grinding etc. Has anyone experienced this? Any advice or tips in this regards.

Should I wait and save up for slip ons or give it a go?

Cheers!
 
Yep, Triumph have improved the welding and baffling of their stock pipes. It can be done but it's fiddly and time consuming.

I would have a go anyway, if it all goes t1ts up, then get slip on / ons.

...

posted from ripped tapatalk.
 
Definitely much harder to do with the newer Bonnies; but it can be done. I have not tried it on the newer models.
 
Yeah, for me it was just a better move this weekend to do a de-cat x-pipe, install a Booster Plug, and take the pea shooters off and replace with British Customs shorty predators. A definite world of difference with my 2017 T100. It awoke the beast and it really holds a conversation now without being obnoxious.
 
Yeah, for me it was just a better move this weekend to do a de-cat x-pipe, install a Booster Plug, and take the pea shooters off and replace with British Customs shorty predators. A definite world of difference with my 2017 T100. It awoke the beast and it really holds a conversation now without being obnoxious.
Very good. TUP
 
Hi guys, great post. One question, is there anything to do differently with an EFI version, like mine? Mapping?

Thanks!
Hello Babbydad, Im new to this forum but I might have an answer for you. I have a 2018 T120. The ECU on these bikes is apparently from what Ive read addaptive and to adapt most modifications to them I have read the following sequence.
First start your bike from cold, let it idle and dont rev till the cooling fan kicks in, then let the fan run its cycle untill it switches the fan off. Then turn the bike off. Turn the bike back on and take it for a ride apparently this prompts the ECU to adapt to any changes in the engine like exhausts etc.
Failing that you can take your bike to the local dealers and they will remap it for about $50 here in Australia. If you have something like a two into one exhaust they can remap the bike to suit an Arrow exhaust as most of the two into ones are the same or very similar.
Hope this helps.
 
@Red26 Appreciate you giving detailed info which benefits all, however, gabbydad has not been seen since 2010. Just put your cursor over their username to tell when members were last seen/active if your not aware of this feature already.
 
My friend who is a motorcycle tech tells me that straight pipes create problems for the carburetor because in order for the bike to function properly there needs to be a small amount of back pressure which you do not get with a baffless (if there is such a word) straight pipe. Someone removed the baffles out of the '79 before I bought it and it sounded loud but I bought a new set of reverse cones and it is almost as loud. I even bought a sheet of 1/2" fiberglass and re-baffled the shorty mufflers. I may sell them.
 
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