Thoughts on Thrush Mod
brucehaslam
Posted 2011-02-08 12:25 PM (#78969)
Subject: Thoughts on Thrush Mod


Puddle Jumper

Posts: 28
Mesa, AZ United States
Finally got around to putting these puppies on. Still trying to decide on the resonator tip. For those of you looking to do this mod, chapelli video is superb. Some of the problems/situations I ran into when I dove into this. First off, I did not remove the lower panels. After removing the heat shields, I took a hack saw and cut the two straps/brackets that are welded on each stock muffler and attached to the bike. (I was not planning on reusing the stock pipes so I figured it was a lot faster and easier to do this than to removed the lower fairings.) Kind of a sledge hammer approach but that is what I did. The only thing holding the muffler on the bike now is the front muffler clamp and the bolt holding the muffler on the back of the bike. After removing both the clamp and the bolt, applying some oil penetrant on the area where the muffler attaches to the exhaust pipe, the muffler came off easily. I am attaching some pictures of what I did. Hopefully it will make sense and help someone.

There are a couple of problems that I found that needed to be solved. The thrush muffler is a smaller diameter than the stock pipe. This causes two problems. One, to keep the pipe in line with the exhaust pipe, I had to install a 1" spacer between the bracket on the back of the bike (see picture) and the thrush muffler. I used a piece of 1" square steel tubing that I had hanging around. Drilled a hole on one side of the tubing and attached it to the back bracket using a 1/2" bolt and a lock washer and tightened it really tight. This 1" spacer worked perfectly as the thrush now comes straight out of the exhaust pipe, straight back and just touches the spacer tube. Incidentally, to get a good seal on the muffler to exhaust pipe, I cut with a hacksaw, four slits on one end of the muffler as long as the muffler clamp is wide. (see picture). After sliding the thrush onto the exhaust pipe I tightened the muffler clamp up front and I then used two stainless steel pipe clamps (two instead of one just for additional safety and stability) and clamped the thrush to the steel tube. These two pipe clamps combined with the front muffler clamp tight make the muffler very rigid and tight. No movement whatsoever.

The second problem associated with the smaller diameter has to do with the fact that when you put the heat shields back on and tightened them to the thrush, there is a space created between the front heat shield and the rear one. I experimented with spacer material and eventually just used some pipe hanger material which I folded into a 1" long piece until I figured I had the right amount. I used some contact cement to hold these spacers in place on the heat shield and then installed the shields and tightened them down. (the spacers need to be installed on top of the channels that are welded on the inside of the heat shields through which the pipe clamps go. (sorry, forgot to take a picture of that). Both heat shields now mesh together with no space between them. I am now at the point of trying to decide what tips to put on.

Dain, if you read this, I am real curious as to how your tips are working. Having started the bike and taken it for a short run, the sound (even without the resonator tips) is music to my ears. I have had a lot of big vtwins and have had everything from Vance and Hines Pro pipes, to thunderheaders to Rhineharts which I currently have and none of them have as mellow and as deep a tone as these glasspacks. Sorry for the verboseness of this post. Hope it helps someone. Going to try and add some pictures.

Explanation of photos:
  1. 1st photo shows left side with stock muffler removed. Note the rear bracket with the hole in it to which a spacer bar will be attached. Also note the bracket just in front that I cut off with a hack saw.


  2. 2nd photo is just a close up of that rear bracket.


  3. 3rd photo is just a shot of the 1" square tubing in which I drilled the 3/8" hole ( I previously said it was a 1/2" hole. not so.


  4. 4th photo is a shot of the spacer tubing attached to the bike.


  5. 5th photo is another shot of the spacer taken from the rear to show the relationship to the exhaust pipe up front.


  6. 6th photo just shows the cuts I made in one end of the thrush so that the muffler clamp can create a good seal. (Note: make sure you don't cut them too deep)


  7. 7th photo is of the thrush attached to the exhaust pipe and shows the proximity of the muffler to the spacer bar. It just touches it.


  8. 8th photo shows how I attached the muffler to the spacer bar with two pipe clamps.




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johnnyvision
Posted 2011-02-08 1:59 PM (#78978 - in reply to #78969)
Subject: Re: Thoughts on Thrush Mod


Visionary

Posts: 4278
I wonder what length you used. I see they make it all the way up to 45"
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Nozzledog
Posted 2011-02-08 2:15 PM (#78981 - in reply to #78969)
Subject: Re: Thoughts on Thrush Mod


Visionary

Posts: 1229
Rancho Cucamonga, CA
Great solution for the back bracket! That 1" spacer worked perfectly. Thanks for the idea. I did almost identical for heat shield spacers. Only needed it for the front one though. Still having problems with the rear heat shield strap and my muffler tips clamp ending up in the same spot.
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brucehaslam
Posted 2011-02-08 4:11 PM (#78991 - in reply to #78978)
Subject: Re: Thoughts on Thrush Mod


Puddle Jumper

Posts: 28
Mesa, AZ United States
I am assuming when you refer to the length that you are referring to muffler length. I used a 31" muffler. Had I to do it over again I would get at least a 33" and possibly even a 35" thrush. I think that I may have problems with the clamp on the tip when I get them and may just end up at a muffler shop and have them welded on.
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team5150
Posted 2011-02-08 4:16 PM (#78992 - in reply to #78969)
Subject: RE: Thoughts on Thrush Mod


Cruiser

Posts: 104
Corona, CA

Here is what I was doing with mine before I decided I like my Atom Bombs just as well as the Thrush mufflers.

I used a cutoff grinder and cut the front and rear parts of the stock muffler off. You have to gut them and open up the inlet and outlet but that's not hard.

Then I slipped the the stock pieces over the Thrush muffler. You line up the rear first and "persuade" it on and then tack weld the front one in place or you could use a muffler clamp. (I have not installed the rear portion all the way yet in the photo below)

This way you have a solid mount in the rear where you need it and in the front it is just augmenting the area where the muffler slips over the header pipe.

Doing it this way also allows you to use the stock tips or Gatling tips.


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Edited by team5150 2011-02-08 4:17 PM
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johnnyvision
Posted 2011-02-08 6:29 PM (#79001 - in reply to #78969)
Subject: Re: Thoughts on Thrush Mod


Visionary

Posts: 4278
Very clever! Stock mufflers not being worth any thing. This clamp harley riders have been using for ever and they come in different sizes.



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dr_reloader
Posted 2011-02-09 8:33 PM (#79064 - in reply to #78969)
Subject: Re: Thoughts on Thrush Mod


Tourer

Posts: 537
, FL United States
Now that is a pic of a nice organized and clean workbench
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Nozzledog
Posted 2011-02-17 11:14 PM (#79646 - in reply to #78969)
Subject: Re: Thoughts on Thrush Mod


Visionary

Posts: 1229
Rancho Cucamonga, CA
For those not ready to cut up our old pipes and would like to use the hangers also, this is how I did it. I put the hanger strap between the two hose clamps holding the 1" square steel tubing (pic 1). To get the correct spacing for the heat shield to line up, you will need to run a spacer under the front heat shield strap. this is what I did (pic 2).



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Attachments 2011-02-17 12.35.57-1.jpg (36KB - 13 downloads)
Attachments 2011-02-17 13.00.42-1.jpg (29KB - 8 downloads)
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team5150
Posted 2011-02-18 1:41 AM (#79651 - in reply to #78969)
Subject: Re: Thoughts on Thrush Mod


Cruiser

Posts: 104
Corona, CA

?

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Here's the rest of it. It isn't just a pretty face - it has a lot of wrenchin done it it with restoration of a 39 Ford Phantom coupe and two Chevelles.

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Man314
Posted 2011-02-18 8:04 AM (#79663 - in reply to #78992)
Subject: RE: Thoughts on Thrush Mod


Tourer

Posts: 575
Spirit Lake IA "Birthplace of Victory Motorcycles"
team5150 - 2011-02-08 4:16 PM

Here is what I was doing with mine before I decided I like my Atom Bombs just as well as the Thrush mufflers.

I used a cutoff grinder and cut the front and rear parts of the stock muffler off. You have to gut them and open up the inlet and outlet but that's not hard.

Then I slipped the the stock pieces over the Thrush muffler. You line up the rear first and "persuade" it on and then tack weld the front one in place or you could use a muffler clamp. (I have not installed the rear portion all the way yet in the photo below)

This way you have a solid mount in the rear where you need it and in the front it is just augmenting the area where the muffler slips over the header pipe.

Doing it this way also allows you to use the stock tips or Gatling tips.


?

 

Things like this are why I LOVE this site! 

team5150,

Can I assume that following this method, I could install these bad boys that I'm ordering from a member on this board without worrying about resonator tips? Is the sound still awesome without resonator tips? I was wanting to do the Thrush mod, but didnt know if I could do it with my new custom tips.  This may have answered my question.  Thx!





(Tips053.jpg)



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Attachments Tips053.jpg (59KB - 9 downloads)
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Man314
Posted 2011-02-18 9:03 AM (#79668 - in reply to #78969)
Subject: Re: Thoughts on Thrush Mod


Tourer

Posts: 575
Spirit Lake IA "Birthplace of Victory Motorcycles"
Two other things team 5150,

1) Are those 31" or 35" Thrush? Which in your opinion would work better to attach standard tips?
2) Why did you stay with atom bombs?
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team5150
Posted 2011-02-18 7:45 PM (#79740 - in reply to #78969)
Subject: Re: Thoughts on Thrush Mod


Cruiser

Posts: 104
Corona, CA
I assume that you are ordering the Thrush mufflers. I used the 31" ones although the 35" would also work.

I cut off the rear part and pulled the insides out keeping the outer barrel. You will have to "persuade" it on with a block of wood and BFH. I had to cut a hole in the end of it large enough to allow the reducer to go through the end part that has the mounting flange for the tips. That is why I did it that way to begin with. I wanted to have a secure mount and retain the ability to mount any of the available exhaust tips on it.

You could use the front part that I cut off or just use a clamp on it. It isn't as important to align it as the rear is.

I did all this just messing around on day and when I put the Thrush on one side of the bike and the Atom Bomb on the other I really couldn't tell much of a difference. I got the AB's from a member for $250 with the Gatlin tips so I was happy.

It's basically doing the same thing they do with the AB's. Pull out the core and replace it with a muffler keeping the mounts all stock.
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txvision2013
Posted 2014-01-16 2:37 PM (#150570 - in reply to #78969)
Subject: Re: Thoughts on Thrush Mod


New user

Posts: 1
Those photos were tons of help. I've started with the thrush mod in the evenings when I get home from work and hope to finish it Saturday morning then out for a ride. I'm no mechanic but I do know which end of a screwdriver to hold. This mod isn't all that difficult.
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my13visionness
Posted 2014-01-19 9:26 AM (#150633 - in reply to #78969)
Subject: RE: Thoughts on Thrush Mod


Puddle Jumper

Posts: 14
East Troy, WI United States
I just finished my thrush mod (1-17-14)Friday afternoon. WOW very nice sound. I am happy.
I did things a little different. I did use the 31 inch thrushes, but used Magnaflow 35136 Exhaust Tip 2.5" Inlet 5" Long 4" Outlet. I welded on the tips directly to thrushes. Then welded a bracket to thrushes to go to rear mount.
Then ground down attachment nuts on the inside of OEM tips. Tip now fits over Magnaflow tips. I used the 4 mounting screws holes on the tip to attach them. I will take pictures today. It turned out nice.
And if you do this mod they sound sweet!!!!!!
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