The hole cutter I used is manufactured by General Tools.  I don't have a part number but I can find them with a simple google search "General Tools Hole Cutter".

That is really disappointing to hear of the pipe & muffler irregularities.
The set I got fit the head as it should; the pipe itself was smooth and straight; the muffler was on the loud side but it did have a baffle, don’t remember what exactly but it was metal and not fiber.

It looks like this when it's ready to rock-n-roll with the exception that the HSS tool bit is installed instead of the as delivered (pointed bit).  Also, I plunged the bit into the face of the flange, not the OD.  See the pic I posted originally.

As I mentioned earlier, this is waaaaaaay too much trouble.  It does a nice job but a Big Ole File will do the job just fine.  Just keep track of the wall thickness.  Use the wooden clamp to hang onto the pipe.

Regarding the quality.  Both of my Mac header pipes are excellent quality as far as finish and bends.  They are double wall and plenty stout.  The chrome on the original is good as is the flame spray on the latest purchase.  As Lancer mentioned, the original offering fit just fine, flange was perfect.  And once I trimmed the flange on the second purchase, it fit like a glove.  Everything fit just fine.  The muffler mount is solid and aligns correctly.  Muffler to pipe joint is tight and leak free.  Clearance is good everywhere.

Of course, the oversize flange is inexcusable.  To me, that's primarily on Dennis Kirk.  They have to know that this problem exists so they should have said up front that it's messed up.  Dennis Kirk sold us the exhaust systems.  I know Mac made em wrong, but Dennis Kirk collected our money.

I still think it's a great price for an exhaust system, even if you have to do a little work on that flange.  But oh boy, that noise.  Have to find a solution for that noise.  

Dave, I suspect your idea to force the flow out and back in will do a pretty decent job of reducing the decibles but it will also probably strangle the flow a bit.  Also, congrats on successfully reducing the OD of your flange in record time.  One hour sounds a whole bunch better than all day.  My compliments.

It's loud. No doubt about it. I like it. But it won't work for my morning commutes so I'll be taking the MAC muffler off and going back to the Yoshimura slip-on. I doubt it will help anyone due to the horrible quality, but I uploaded a video taken from a Samsung phone to my instagram (it was warmed up before I filmed). I haven't been able to ride it yet (still need to purchase a tire), but it sounds faster  

@Dave there were a few times while filing and dremeling that I looked up at the computer screen and read the words in all caps, "EXACT FIT" and mumbled a few choice words.

For a clamp, I ran to AuzoZone and picked up a 2" universal clamp. It's ugly, but it works.

It's hard to say without a test ride, but overall I think I'll be happy for the price. I may go ahead and do the exhaust port opening after riding for a bit.

Dave, I know you are a engineer but, that sounds waaaay too involved.
When the baffle blew out of my Dyna, I took a 9 1/2'' piece of water pipe made a plug for the end and a sleeve to fit the back end of the muffler, then drilled 16 - 13/64'' holes in the sides of it. ( 1/4-20 tap size if it was too many )  
I am happy with the sound, but if you wanted to play around just one bolt holding it in so it would be easy to ''tune''.
I would think the larger the holes dia. should give you  a ''deeper'' sound, and if you get too many holes just cut a new piece of pipe and start over.

Well I guess one temporary way to test my approach - would be to shove some course steel wool in the place I want to block the perforated core.....then pack it tightly into place by using a bar on both sides to squash it in place.

I know it will burn out before very long - but it would allow for a short term test.  When you want the darn thing out.......I suspect a 70mph run for 15-20 minutes would cook it right out of there!

verslagen1 wrote on 10/15/20 at 15:42:09:



I will make sure Lily and Deb are not on the receiving end!