hide You are viewing an archived web page, collected at the request of Road Star Clinic using Archive-It. This page was captured on 21:46:41 Feb 23, 2018, and is part of the Road Star Clinic Closure collection. The information on this web page may be out of date. See All versions of this archived page.

Make your own performance Baffles

Written by Mark Penland (Mariner)   
Saturday, 10 July 2004

Here are the info/instructions on how I made my Thundermonsters. I followed the instructions posted by RUBADUB11 on the forum. I’ve also include a pic.

Here are the instructions to make a set of home made Thundermonsters. The dimensions here are for 2&1/8 I.D. Pipes (mine are V&H Longshots). You will need :

2 - 2&1/8 O.D X 2 O.D. reducers

2 - 2&1/8 O.D X 1&7/8 O.D. reducers

2 small pop rivets

2 - ¼ by ¾ bolts with nuts and lock washers, I used stainless steel to alleviate future problems.

I would suggest using same size bolts that are holding you present baffles in place.


1.) First thing you should do is check the reducers for fit in your pipes, also check for burrs on the inside might as well get it all smooth. I had to file the edges of mine so they would slide in and out easily

2.) Take one of each and slide them together one inside the other, drill the correct size hole for your pop-rivet and secure the two pieces, do the same with the other pair. I made mine about 6” long

3.) Drill the correct size hole for the retaining bolts. You will drill this hole in the 2 1/8 x 2 reducer, you want the inside of the smaller reducer pointing out.

4.) Slide them puppys in put the bolts in to secure them and your ready to go.

I made a set following these instructions from “The Roadstar Forum” posted by RUBADUB11 and have been very happy with them. When I originally pulled my baffles and was running nothing the pipes sounded harsh and the Jake-Brake popping on decal was really aggravating. Prior to the recall and having H/C Pistons done the sound was real mellow and on decel sounded like a small block Chevy no popping or backfiring just real smooth. And yes I felt there was more power there than without the baffles.

However since the install of the H/C pistons this thing is LOUD a lot more authority comin outta the backend than before.

So there it is, there are a lot of different options on this, they could be welded together, you could have muffler shop knock out a set, and you could buy the real thing. I did mine because I like the hands on thing and it only cost me maybe 8.00 total and an hours time.

Good Luck!


Questions should be asked in our forum (Use discuss link below). The forum is very active and you stand a good chance of getting your questions answered there. If you would like to leave feedback for the author, or have additional information you think will benefit others, please use the comment section at the bottom of this page.

Discuss this article on the forums. (5 posts)

DISCLAIMER: This information and procedure is provided as a courtesy and is for informational purposes only.  Neither the publishers nor the authors accept any responsibility for the accuracy, applicability, or suitability of this procedure.  You assume all risks associated with the use of this information.  NEITHER THE PUBLISHERs NOR THE AUTHORs SHALL IN ANY EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, PUNITIVE, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, OF ANY NATURE ARISING OUT OF OR IN ANY WAY CONNECTED WITH THE USE OR MISUSE OF THIS INFORMATION OR LACK OF INFORMATION.  Any type of modification or service work on your motorcycle should always be performed by a professional mechanic. If performed incorrectly, this procedure may endanger the safety of you and others on your motorcycle and possibly invalidate your manufacturer’s warranty.

Quote this article on your site | Views: 44385

  Comments (2)
Excellent Results!
Written by Cincibkr, on 11-25-2009 20:28
I fabbed up a set of these as described, except I used 1/4"x 1" thumbscrew in place of the regular screws. I installed the thumbscrews inside the pipe and perpendicular to the exhaust flow to sort of mimick the Thunder Monster washers. I can't be happier with the results, the bike sounds incredible, it pulls harder and the lower end torque has been restored!!! And the kicker is, this only cost me about $12 bucks!
Written by vettesare1, on 06-08-2008 14:35
SIR,On the web for thundermonster baffles they show a washer in the center,is this for sound or backpressure????your instructions does`nt cover this...i am like you i would really like to make my own.Please Help jamess null :?

Only registered users can write comments.
Please login or register.

Powered by AkoComment Tweaked Special Edition v.1.4.6
AkoComment © Copyright 2004 by Arthur Konze - www.mamboportal.com
All right reserved