[JRR]

I bought a Mac 2-1 header/muffler kit for my 82' CM450C

&

Installed it, Started up the bike!!!



until i rev'd it....



So I hopped on the computernets and found no definitive fixes. But I found a contact on MAC Performance's website "https://www.macperformance.com/contactus.sc" and received a response.

Drill out the rivet (1/4" or #7 drill bit) on your muffler.

Push out the baffle

Mine fell out!

The fix consist of yourself bending up the top cap in the four quadrants.

You'll be bending the part that fits inside. The buzz is coming from the top cap is vibrating against the inside of the megaphone creating a audible frequency (like a clarinet reed) So essentially your giving it a more rigid support.

Its hard to see, but this is a pic of myself who bent (belled) the baffle (internal end). I used a 420 Channel Lock tongue and groove piers. You don't want to bend it too much, You'll have to reinsert it into the megaphone.

Line up the hole where the rivet was.

I used a rubber mallet and a small piece of wood to pound the baffle back into the megaphone.

NOTE: Don't forget not to pound the baffle in too far.

Install a rivet or small stainless steel screw locknut and nut. Put it back on the damn bike and say goodbye to that BUZZ you somehow paid for.



I hope I helped somebody

 

[longdistancerider]

Thank you for this post, I'm absolutely certain it will help a number of people.

 

[Mydlyfkryzis]

I have a MAC exhaust on my 360, sme sort of baffle...FYI, use Stainless nut and bolt, put never-seez on it. This way it won't rust and will be removable if needed in the future.

The clamp that holds the muffler to the header pipes. On mine, it was 2 1/2 inch. I went to Pep boys and used a stainless steel muffler clamp. Again, no rust, and keeps the muffler on.

 

[ahm1]

does it still sound like a wounded cow when riding? I just packed some exhaust matting round the baffle and it got rid of the rattle and drony exhaust note

 

[Mydlyfkryzis]

No, just loud.

I had packed mine, but had to add screen to meet the packing from blocking the exhaust.

It has since dissolved and it is back to loud.


Sent from planet Earth using mysterious electronic devices and Tapatalk

 

[ahm1]

I gutted mine as the packing had mostly come out through time, so I thought id give your method a crack and it works great

Sent from my HTC One X using Tapatalk 2

 

[Drey6]

I heard so many bad reviews on the muffler that was included I set it aside and grabbed one of the Emgo shorty mufflers. But, if I had known this beforehand I could have saved myself some money. Ill have to link this to my upholstery guy since he is doing the labor on my seat for my Mac muffler. Good post.

 

[JRR]

http://shop.macperformance.com/MAC-2-in ... egoryId=-1

I think its a new product?! i'm going to buy and try it out.

Its a lot more open and loulder than the stock.

 

[Drey6]

If I were you I would just buy another muffler instead.

 

[JRR]

I trashed the mac exhaust! i gave up on it. I oreded a Dime City Cycles 2" shorty muffler! ($109)

sounds great!!!

(I'll add video and pictures soon!)

 

[ekryski]

I trashed the mac exhaust! i gave up on it. I oreded a Dime City Cycles 2" shorty muffler! ($109)

sounds great!!!

(I'll add video and pictures soon!)

It's been a while since you've posted but I'd love see a video if you've got it.

 

[btparker]

Just like to add I bought a mac muffler. Installed it and rode 1 mile. Brought it to the shop to have to rejetted (140). Didn't know the muffler was held by only a single rivet and that baffle flew off on their 5th test ride. Yeah...just straight out the muffler. Mac wouldn't send me a new kept giving me the run around. That guy who does the warrenty stuff is a dick. I bought a new baffle for ~45$ and it installed but PLEASE if you buy one of these, replace the rivet with something more secure

 

[apdaniel]

My pipes where bent incorrectly so that they hit the frame. I tried to get a new pipe. I could see how it was bent too much on one of the bends. Finally I stated I actually had a cl360. Then he said the heads where different. Why lie? Then be a dick about a insufficient fastener. I also had a rattle so I did the cone bend. Then I drove that thing in there deep drilled 2 new holes. Used stainless hardware with an all metal lock nut. All is good now, but I have to wrap a certain section with fiberglass for a vibration. I'm 50/50. It's a nice exhaust, after some slight changes. But don't expect ANY customer service.

 

[btparker]

I tried to fix described in this thread. I pulled it off twice and adjusted the diameter of the baffle ends to better fit the muffler. It went from sounding like an old dying cow to an angry dying bull. I think this muffler is just garbage and I am embarrassed to even ride with that **** on. What a waste of money!

 

[daktah]

i finally got around to taking my new mac 2-1 for a test drive and got a nice buzz/resonation at 6-8 grand or so (tacho is crapo) when you hammer it so i popped off the rivet to try this fix only to find that at some point they switched to a one piece internal scoopy thing, so idk if its whats vibrating or its the outside end but i ordered some packing so we will see if it fixes it (needs it anyway, sounds like a fart can). of course it shouldnt have this problem from the factory, but if all it takes to fix is a $15 roll of fiberglass and a new bolt i wont be too upset considering the price point and it being pretty much the only aftermarket header back still available.

 

[longdistancerider]

Sad that things have changed for the worse, didn't think they could go from bad to worse.

 

[daktah]

well i packed the muffler like a week ago but drivability problems were hampering me trying it out, now the bike has decided it wants to be more reliable for the time being so i took it out and the packing made quite a huge difference. i only put 1 layer of ~0.7" packing around the inside of the baffle (in between the cup and the rear cap) and secured it with a stainless zip tie and had to hammer it in with a soft mallet because even 1 layer was a tight squeeze. end result is it no longer sounds like a rice rocket fart can and the buzz is almost 100% gone. for $15 and 5 minutes of work im pretty happy with the result.
here is a short video on the sound difference:

note that the mic makes the packed muffler sound waaay bassier than it is, there is almost no bass in the note.
the exact stuff i got: https://www.amazon.com/gp/product/B003O6VWAE there is more than enough here for 2 mac mufflers for you 2-2 guys too.