Put Vance and Hines Twin Slash 4" round slipons to my 08 Road King. Wow it's loud! The muffler is simply a fat long empty space with minor baffling on outside walls to pass sound right through. I added the quiet baffle inserts part # 21892 but it barely did anything and is still on the verge of uncomfortably loud. It's a tiny insert, here's what I ordered...

http://www.denniskirk.com/vance-and-...rd/4405196.sku

Seen other baffle inserts that look like long cones with holes all over that think would seriously quiet it down. V&H doesn't appear to have anything like that for this slip on. Went all over town to see if could find something to no avail. Anyone know of some generic type part I could try in it? Figure I could have shop weld it in place if needed.

 

that looks like a torque cone thay guys use with straight pipes screwed to a piece of fence pole I.. if those r too loud maybe trade with someone on here for a different set

 

You need a baffle thats minumum 12" long thats capped on the front end with 1/4" holes all the way down. Once you find or make one like that youll need muffler wrap to wrap 80% of it at about 1" thick leaving the other 25% from the front unwrapped. Then take it out and get a feel for the sound, torque fuel requirements etc. Do not wrap the whole thing or it will be like stuffing a rag into your exhaust and the wrap will smoke with possible burning involved. You can use stainless steel wire to kep the wrap in place. If you want more sound etc you expose more open baffle at the front. If you want it quietter, cover up not to exceed 85-90% of the front. Your map will likely need to be modified however.

 

Big City Thunder makes baffles that fit in the header before the muffler, and they say it stops all that, plus improves low end torque:
THUNDER MONSTER BAFFLES FOR LARGE DIAMETER MUFFLERS, If you have installed aftermarket mufflers ... Big City Thunder has Thunder Monster baffles that install in the exit end of the head pipe where it joins the muffler.....This particular application is called a head pipe installation and with our Original Thunder Monster baffles will provide a deeper, throatier, aggressive hot rod/hot bike sound as well as improved performance....
Original Thunder Monster baffles $79.95 per pair + S&H*

 

fyi.... Ended up cutting the flare end off the V&H quiet baffle and adding a second baffle that fit on the cutoff end. The second baffle was 8" long and made too quiet. After experimenting got it down to about 3" and pushed the baffles in some inside the second baffle until got that sound I liked.... just enough to take the edge off but still loud enough that has that Harley sound.

Here's the second baffle added on.

https://www.denniskirk.com/H44738.sku

 

That's a lot of bafflin'

I had the same exhaust....... They were really deep in my opinion, sold them to a forum member..... I had them on stock headers, I'm assuming you're using an aftermarket headpipes if they're too loud?

 

Na just slipons on stock headers. When first repiped to my old 96 Heritage Softail I remember being stunned how loud they were but quickly got used to it. Just couldn't get used to these V&H Twin Slash even after a couple hours of riding. Read others complaining about these slip ons even with standard quiet baffle so not just me. Just never been a super loud type.