MAC 2 into 1 Exhaust Install


XS400 Enthusiast
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Fayetteville, NC
MAC 2 into 1 Exhaust Install (Video Added)

This is my installation of a 2 into 1 from MAC, just about everything can be done with 12-14 mm sockets and wrenches. The kit comes with header pipes, muffler, and a little bag of hardware. Unfortunately there were no instructions but it was simple enough to figure out.

First you'll want to remove all of your stock exhaust components, save the hardware because you will have to reuse some of it.


Mount the header and use the old nuts to secure the exhaust flanges. One thing I thought was odd was there there was not supplied gasket between the header pipe and where it bolts to the head. I called MAC tech support to see if there was maybe suppose to be one or if there was something I was suppose to use. Their reply was, "the kit comes with everything you need"... -1 tech support....

Next you want to use the supplied chrome collar with bolt, nut, and lock washer to attach the muffler to the exhaust pipe.


You should have an extra bolt, nut and flat washer. Slide the bolt into the side of the muffler and attach it to the supplied flat mounting bracket with the nut and washer. Attach the other end of the bracket to the bike where the stock exhaust was using the old hardware. I didn't have the old muffler so my hardware wasn't there, I just use a regular bolt and lock nut.

At this point you should have 1 angled bracket left over. I never did figure out where this goes or what purpose it serves. I'm open to suggestions....


All in all it was a very easy install. It sounds good and looks even better, however it's not perfect. I noticed an exhaust leaks, coming from the right side exhaust flange. I looked through the MAC forums and it seems someone else had the same problem. MAC replied to him with the response "Try turning the collar around". Surprise surprise, it worked....+1 tech support....

The next problem is where the exhaust pipe comes down on the left side it makes contact with the frame. I can see this causing problems a few years down the road after it wears a hole through it.


I took it on a ride today and it's definitely going to have to be rejetted. I was sputtering and popping all the way down the street. Seems like a task for the next warm day.


Nice! Looks TONS better! Thanks alot for the write-up; it will no doubt help alot of people who are thinking of buying the MAC system! When you get it jetted right, post up your settings; always useful information. Thanks again!
Great post VLAD, thanks for the report and the pics.. It is odd that the left pipe is rubbing the mount, that sucks. Is there any room for adjustments by slightly rotating the pipe before you tighten the muffler clamp??

Looks great, you do like the exhaust note right ?? haha..

Despite the few problems I mentioned I do like the system. Perhaps those are just problems exclusive to my bike. I'd be curious to see if anyone else has the same issues if they buy the same system.
this should be a 'sticky' thread for future use!!
Nice job on the write up...I've been eyeballing this set up myself.!
as to the rubbing...what if you toleranced the edge of the motor mount?
there looks to be plenty of meat there to take off an 1/8" shouldn't hurt?
Any chance for a YouTube video so we can hear what it sounds like?

The new exhaust looks really good!
the later sohc, have rubber mounted engines. My bike is an early one with no projection on the frame so would present no problems.

like skillzman said a little bit a movement should clear the mount. I would use yam gaskets (they are usually stuck in the heads)

I think I'm going to take your idea and try to adjust it to get away from the frame a little. If that doesn't work I may just go at it with the dremel and take a little of the mount.
I've run into similar problems,loosen the exhaust flange nuts,then put a block of wood,1/4,1/2,etc.When you tighten up the nuts,then knock out the block,there should be a space left to clear the mount.On another note,I need a set of pipes like you removed,as I want to put "drag pipes"with glasspacks.If you decide to sell,tell me and I'll figure out how to post my e-mail for you.thanks. lha
Thanks for the idea, I think I just my try that this friday when I'm off. I was considering using the old pipes whenever I start my bobber conversion but the DMV is really strict on making sure you have baffles in your exhaust when you get it inspected so I would definitely consider selling.
i just ordered the same system and a jet kit with pods. cant wait to ride it.
I just installed the same system on my bike...had a similar clearance issue you had around the engine mount brackets.
Once I had them relatively evenly spaced between the brackets...about an 1/8" clearance each side.
I tightened the flange nuts down good and snug,so they wouldnt move ...then I grabbed the collector and tweaked the pipe down forceably....kinda caveman style...just enough to create some additional clearance...seemed to work alright.
I tried to move it around and it still doesnt touch the frame mounts at all.