Author Topic: CM400T New Mac Exhaust Rattle (Read 933 times)

chugger93 · « **on:** April 28, 2012, 05:41:00 AM »

Hi;

New here, and struggling with this. JUst got my new 2 into 2 mac exhaust installed on my 80 CM400T. It rattles extremely bad and I've heard its common. I've researched enough where I heard you can remove the baffles too so you can pack it and help eliminate the rattle, etc. I drilled out the one rivet, and pounded the baffle with a rubber mallet very very hard for hours with no success. So I'm either stupid or this thing isn't budging.

What options do I have here? I can't live with this rattle. Anyone else with this experience?

Thanks so much!

KB02 · « **Reply #1 on:** April 28, 2012, 03:28:34 PM »

How are you pounding on the baffles? From the front to pound it out the back?

Lovely MAC's...

chugger93 · « **Reply #2 on:** April 28, 2012, 06:52:12 PM »

Well I took the megaphone off and worked on it in my basement. Basically I tried using a wooden stake, PVC, etc shove it down the back or small side till it hits the bottom or outlet and pounding it using a rubber mallet. I used a lot of force but it didn't budge an inch.

I heard of trying to shove steel wool in the outlet too which helps the baffle rattle.

KB02 · « **Reply #3 on:** April 29, 2012, 05:35:20 AM »

Okay. Just wanted to make sure you were going the right way. Some guys don't...

The MAC baffle design is not the greatest. It leads to a great deal of buzzing (like you are experiencing). It is the inner part of the baffle that is vibrating. Just stuffing the baffle with packing will only serve to stop the exhaust flow with the way the exhaust is designed. Your best bet is to simply build a new baffle that can properly be packed (and re-packed).

If you can, post a pic. Your best bet might be to keep pounding, but a pic might give us something else to spot that you might have missed.

chugger93 · « **Reply #4 on:** April 29, 2012, 08:34:02 AM »

Here's a few pics. My bike is the first pic with the new exhaust on it, and the rest are the megaphone, etc closer up.

I did put a little steel wool in the back pipe and pounded it down there, but put it outta the way so gases can still kinda flow. So that's good. I think it's helped, but havn't actually driven the bike under high RPM's to truly test. So I don't think it's really limiting the exhaust flow that much since I can still see around it.