Topic: Improving on the MAC exhaust

[tennesseebreeze]

When I took the baffle out of the 4 into 1 MAC exhaust I have on my cb500, I was er...baffled. What in the hell is this cheap ass thing they did here? Two tubes, one flattened, overlapping and welded. I guess the idea being the exhaust gets forced into a chamber and has to find it's way out again, thereby reducing sound and providing back pressure. But what an inelegant way of doing it. They could mearly plug in a baffle from another vendor and it would cost no more than this half-assed design is to fabricate.

Anyway, with this setup, the bike was running like crap and sounded even worse, like an asthmatic frog under a blanket. So here's what I did to improve it. It only took about an hour to do.

I cut the welds holding the two pieces together, cut short the pipe that was flattened, and welded the two pieces together. Then I drilled a bunch of crude holes into the tube (I was in a bit of a hurry, so no careful spacing. After filing the burrs on the inside I wrapped the tube with course steel wool and reinstalled it. It sounds and runs 1000X better. So anyone looking to improve their budget pipes- take a look at the baffle. It makes all the difference.

[Jerry Rxman Griffin aka MuthaF'er]

Good job. I was at first hoping you just re-installed the back half and were reporting on that.

[BomberMann650]

I improved on my MAC exhaust by attaching an old yoshimura stub can to it.

[tennesseebreeze]

I improved on my MAC exhaust by attaching an old yoshimura stub can to it.

That works even better. I got the idea for this baffle from the innards of my 750's Yoshimura exhaust. Though their's has a little more R&D behind I think.

[evanphi]

I improved my MAC by putting a Cone Engineering silencer on it. Headers are #$%*e and rusting through the paint, but sounds awesome.

[BomberMann650]

I improved my MAC by putting a Cone Engineering silencer on it. Headers are #$%*e and rusting through the paint, but sounds awesome.

Oh that's not the original paint on my mac headers either.  That black coating they came with burned off in the first few minutes of run-time.  VHT flameproof paint to the rescue!

[evanphi]

I improved my MAC by putting a Cone Engineering silencer on it. Headers are #$%*e and rusting through the paint, but sounds awesome.

Oh that's not the original paint on my mac headers either.  That black coating they came with burned off in the first few minutes of run-time.  VHT flameproof paint to the rescue!

I used the VHT header paint and it also baked right through.

Going to try some BBQ paint in a few days. 

[BomberMann650]

I improved my MAC by putting a Cone Engineering silencer on it. Headers are #$%*e and rusting through the paint, but sounds awesome.

Oh that's not the original paint on my mac headers either.  That black coating they came with burned off in the first few minutes of run-time.  VHT flameproof paint to the rescue!

I used the VHT header paint and it also baked right through.

Going to try some BBQ paint in a few days. 

VHT had some very specific curing requirements.  It was like 8 hours room temp cure, then 2 intervals of 10min hot cure on idling bike, cool down, another 15 minutes at idle, cool down, and finally 25 minutes of.  So for an hour an a half, I got to watch the paint dry.   
 
Mine was looking good until I touched a warm pipe with a glove trying to flick a bug away.  Oops

[tennesseebreeze]

I improved my MAC by putting a Cone Engineering silencer on it. Headers are #$%*e and rusting through the paint, but sounds awesome.

Oh that's not the original paint on my mac headers either.  That black coating they came with burned off in the first few minutes of run-time.  VHT flameproof paint to the rescue!

So that's why I've had to paint mine 3 times. Reading instructions isn't my strongest suit.

I used the VHT header paint and it also baked right through.

Going to try some BBQ paint in a few days. 

VHT had some very specific curing requirements.  It was like 8 hours room temp cure, then 2 intervals of 10min hot cure on idling bike, cool down, another 15 minutes at idle, cool down, and finally 25 minutes of.  So for an hour an a half, I got to watch the paint dry.   
 
Mine was looking good until I touched a warm pipe with a glove trying to flick a bug away.  Oops

[dgreenbluet]

Thanks for the great info!

I honestly hate my MAC exhaust, I had no idea it was so cheap, so time to try and spruce it up and make it last a few years. 

[tennesseebreeze]

Thanks for the great info!

I honestly hate my MAC exhaust, I had no idea it was so cheap, so time to try and spruce it up and make it last a few years.

After my modification, it sounds so much better. I had bought mine new and installed it on the bike. I didn't even get to run it before rust spots began to appear on the chrome muffler. The chrome is thin as hell.

[hsas.69]

I did the same thing to my 750 but instead of holes in cut slits in the baffle pipe and dented one side in to "catch" air, then wrapped with stainless steel dish scrubbers. Sounded way better.

Sent from my SM-T377R4 using Tapatalk

[Airborne 82nd]

 evanphi
I used the VHT header paint and it also baked right through.

Going to try some BBQ paint in a few days. 

Then you can throw a steak on it during your next ride.

[BomberMann650]

I did the same thing to my 750 but instead of holes in cut slits in the baffle pipe and dented one side in to "catch" air, then wrapped with stainless steel dish scrubbers. Sounded way better.

Sent from my SM-T377R4 using Tapatalk

And smelled lemon-y fresh

[hsas.69]

Lol... I used the heavier stainless not the finer stuff.

Sent from my LGUS992 using Tapatalk

[NobleHops]

Mac are the Harbor Freight of exhaust systems. We tell ourselves it's good enough, buy the crap, and then secretly loathe ourselves for doing it. :-)

[brewsky]

Took a drill and a dremel to mine, it now has a decent sound,,,,

http://forums.sohc4.net/index.php/topic,106651.msg1193260.html#msg1193260

[70CB750]

I had second hand Mac headers on Dorothy and when the muffler fell apart, I built my own from a piece of exhaust tubing.  It worked well enough, but it was loud.   I like my Quiet Core much better.

[evanphi]

evanphi
I used the VHT header paint and it also baked right through.

Going to try some BBQ paint in a few days. 

Then you can throw a steak on it during your next ride.

I just did my BBQ paint last night. Going to ride to work on Friday with it and have some bacon ready when I get there.