Swapping to MAC exhaust

[crackerkorean]

How hard is this and what all do I need.
I imagine that I need new gaskets but other than that?
I bought nightvisions set a few months ago and now that its getting warmer I want to go ahead and put them on the bike.

Any tips and tricks would be helpful

[Superfly]

It's an easy swap.  While you got the exhaust off, might as well get the gaskets you need (the front and the crush o rings in the back) and just pull the old one off, and put the new one on... It is really that easy.

Tip....
If you are running 82 carbs make sure you have 135 air jets (in the top) I noticed a big difference with the mac pipes....

[Lucky]

Tip:
don't remove the rear Y-pipe with the old exhaust, those clamps are a pain. (your reusing it)  pulling the rear tire gives easier access, but you'll have to leave the upper can loose till the tire is back on, the upper can is in the way of the axel.

[Superfly]

It is a pain, but I did it so I could put all new gaskets in there.... finally got rid of that nasty exhaust leak that way.

[crackerkorean]

I have an exhuast leak at the rear crush ring I guess it is so everything is coming off.

Are the gaskets avalible from yamaha or do I have to get them onthe bay?

[Superfly]

Yamaha still has them, usually a "special order"

[kwells]

Was looking at buying a MAC from macperformance.com...

The question is:  Does this come with the proper crush rings and all hardware needed?  It appears to have it all but just trying to do the proper research first.
Kevin

[crackerkorean]

Not sure I got mine used and on the cheap.

[Brian Moffet]

I'm looking at the photo they have on their web page, and it appears that you'll need the crush washers for the front cylinder, and the crush washers, the pipes coming off the rear exhaust, the copper rings and clamps, and the 2-into-1 y for the rear cylinder.

This means they provide from the connectors on the front (not including the crush washers) and from the single pipe at the back cylinder.

But that's just looking at the photo.

Brian

[kwells]

I sent them an email asking for clarification. SHould hear back within 72 hours according to the confirmation.

[zore]

Bought my exhaust new.  Here is what I found.  The first one wasn't bent properly, the second one was only slightly better.  The instructions are generation number 4432 so they are pretty useless.  It doesnt' come with gaskets.

[louthepou]

You first want to make sure the Y pipe is solid and without a leak.

Then you put all the exhaust system on loose. You start tightening the front, and not too much; the collars up front will bend if the bolts are too tight. (Not to mention stripping the thread in the engine).

You need to check if the bottom (front cylinder) pipe clears the rear wheel axle; when the rear shock is compressed, often the axle touches the bottom pipe. I made spacers that I placed on the brackets so that the bottom pipe is now slightly offset compared to the top one.

Order new exhaust gaskets for the front cylinder.

That's all I can say at this point... Gotta go BBQ dinner!

Lou

[kwells]

Hey another MAC question.
I have a MAC exhaust on my 82 and was thinking about getting it for the other....I cringe saying this but my girl doesnt like how loud it is...but I think the baffles have been taken out.

The real question is this:
How loud is the MAC right out of the box without the baffles taken out?  We were planning a 6 day trip and didnt want to hear the complaining the whole time (even if I am grinning in my helmet).
Kevin

[Lucky]

out of the box they are loud, my friend bought them new for his 83, & they were too loud for him. since they are "straight thru" what he did was grind out the welds from the end cap & remove the center pipe. he then took 2 straight pipes 3/4 of the length of the original, flattened the ends & welded the ends together to make reverse flow mufflers.

then we wrapped them in stainless steel wool from McMaster-Carr (cut this stuff with scissors, don't try to tear it, it'll shred your fingers) it doesn't rust & is a 'cleanable' packing.  this quieted them down considerably & maintained the low rumble the macs added.

i have a picture of the original Mac reverse flow muffler.  they may still have the tooling available & may be able to make you one if you ask, it may be extra..
--Lucky

[louthepou]

Dang! I wanted to be the first one to successfully perform that surgery! :D (I just got a MIG welder...)

Good job Lucky, glad to hear it works 

Will be using that method later this Spring

Louis