Need to make some custom baffles to put race exhaust back on the street

I have these "shot gun" slash end drag pipes I want to reuse on the street. They are straight thru with no baffle cage, diffuser plates or anything inside, just some plain 6061 tubing. The head pipes are off a KZ1000 header.

 

They look awesome on the bike from the back and they are very simple to get on and off.

 

 

 

 

I was thinking I could fabricate a stainless steel mesh tube to insert from the open end of the aluminum "muffler"potion and hold that in with a pin/bolt. The baffling material would just be burrito wrapped into the mesh "sock", not sure but I think a end cap with a center hole would help hold it back against exhaust pressure.

Any thoughts or suggestions?
 



 

Here's one for an old Yamaha from an eBay seller:

 

I'm thinking the portion with the two large end caps (that are close to the ID of the exhaust) and the baffle material in the middle would be sufficient. The Yamaha uses a set screw near the outlet to hold the baffle in place.

The exit end does have a smaller hole in the middle and that end cap does keep the baffle wrap from blowing out the back   It's also held place with wire so it doesn't all get pushed to the back while remaining captive. 

Thanks for that visual. I need to investigate further, I just thought about this today quickly as I was taking that bike apart.

I have not really dug into this yet but my main concern is the small ID of the "muffler" pipe tubing. I need to actually measure it but I think it may be about 1-1/2", not a lot of space to work with like a typical real muffler.

I have only ever re wrapped baffle inners, never designed and built one from scratch. I think I may even have extra some baffle material kicking around.

I know the single pipes may be giving away a little torque on the street, but they are built and ready to use (zero dollar investment) plus they look different. As for the torque I don't think its going to matter all that much as it will have plenty of HP.

Just thinking out loud but if there is not a lot of room for a roll of fiber material, maybe just a all metal baffle chamber?


 

Read up on "lollipops"     old chopper deal
 bolt with a washer welded on the end   two nuts to secure position in exhaust 
.so you can rotate to "tune"
Be well

Shankkole post=925846 userid=54140Read up on "lollipops"     old chopper deal
 bolt with a washer welded on the end   two nuts to secure position in exhaust 
.so you can rotate to "tune"
Be well
 

Yep, been on the internet gather information on making baffles with wraps or no wraps. Lots of info on tuning Harley type straight pipes (basically what I have) to make them "noise legal".

Currently thinking that mechanical without wrap is the way to go.

We do have sound cops here that can pull you over and check dB levels, but I have never seen that, just heard it happens when they want to give out tickets! Locally at idle the max is 92dB @ 20" and 96dB off idle at any throttle setting @ 20".

I do have a cheap sound meter so I can check the noise level.

Once when I started the alcohol bike at my house a guy from the next street over came to complain, told him to get lost and call the cops if he had too... never did. That was 1996 and never saw him again, but my wife tells me he still lives around here.

Shankkole post=925846 userid=54140Read up on "lollipops"     old chopper deal
 bolt with a washer welded on the end   two nuts to secure position in exhaust 
.so you can rotate to "tune"
Be well

Found that DK Customs had the most info on there version of the "lollipop" which they call the "torque insert" there’s has a cup shape which is anti reversion. Seems to be some effort into improving that basic idea so I am going to make a metric version with M8 Allen studs and copy the sizing model which looks like it works well. Pretty sure what I require for my pipes is smaller than there smallest offering is plus they seem pricey for what they are.

I do like the "cup design", it looks like they press the disks over a triangle mandrel. My engine is only 50 ci so I don't think the disk needs to be as thick as they make it which will be easier to bend/press into shape.

You just run these within 2" of the exhaust tip, no baffles.

 

   

 

 

Custom Chrome sell the perforated tubing in a range of sizes, I paid around $20 for a meter. Mine is straight through but with wadding. I hope to find out in the coming weeks how load it is !!

I was up late last night looking at DIY mechanical baffles on Utube and I think I can make something to slip in ahead of the "lollipop" insert if needed. Going to make one of those inserts first, as that looks to be the easiest way to put some back pressure into the pipe and bring the dB's down a bit. I like the fact that I don't have to scrap the slash cut tips

Going out to measure the exhaust tip ID's and bring those parts into the garage for quick access.

The one thing about returning the engine to running gasoline is it will probably run quieter than alcohol. Taking compression out of it will also make it quieter. On alcohol it was obnoxious at best.

It should still sound good as it has some big lumpy cams in it.
 

Yep, Snuff-or-Nots by another name. Used to run those on my Honda Scramblers when I was in high school.  They are becoming commercially available again.

I measured the "muffler" pipes today, they were made out of 6061 round tube, 1.500 OD x .125" wall. ID equals 1.250" so a lot smaller than I initially thought.

Looks like I have about 21" of length to work with as far as trying to get a DIY mechanical baffle in there. If I am putting one of those "lollipop" inserts in then I need to subtract about 3".
 

Got the CAD software fired up and cranked out a preliminary design.

 

 

The "lollipop" is a washer that I am going to "cup" in a arbor press then weld to a M6 Allen stud. The baffle pipe is 1/2 OD CREW tube 15" long with some sheet steel end caps. There is enough room to wrap the pipe with fiber material if needed.