MAC 4-1 Competition Baffle

[Guest]

Anyone running the competition baffle in their MAC 4-1? How does it sound compared to the standard 4-1 MAC baffle? Mine sounds kind of tinny at low RPMs (sounds great above 6k though) and was thinking about swapping it out for the competition baffle. Would I have to re-jet again for this?

Edit: I'm running 102.5s right now compared to the 97.5s the stock 650E has. Needles raised 0.04". Currently running stock airbox with drop-in K&N and MAC 4-1

[rudeman]

I'm not running a Comp baffle. I've never known anyone who actually ran a baffle in their pipe when racing though. The Comp baffle probably has a little more flow than the regular baffle. I think it would require some rejetting.

I'm going to open up the baffle in my pipe by drilling a series of holes in the plates so it will breathe a little better. Did that on the Yoshimura on my 1000ST and it helped. I had to step up the jetting 2 full steps up on the mains after I drilled the baffle. She was already up to 115; bumped it to 120.

[huntb]

The comp baffle is a straight through and drilled baffle as opposed to the normal baffle with an elbow in it and not drilled. I figured I would probably have to rejet 2-3 sizes if I go with it. I might try drilling the standard baffle first.

[Chuck78]

I didn'tcare for the sound of the stock baffle that came with my MAC 4 into 1 on my bike, so I made my own. It sounds like the Mac competition baffle is pretty similar to the baffle that I made for my Mac exhaust. I love the way it sounds, and got lots of comments on how good the exhaust sounded. It was much better sounding while cruising & accelerating than just an open exhaust, although the open exhaust at idle sounds thunderous and impressive compared to with any baffle in.

that exhaust is on the shelf for now until I build up a spare GS 750, and I am running a Vance & Hines, which sounds similar, and is designed similar, but smaller diameter. It has glass packing and sounds great but quieter (still quite loud). V&H also make a competition baffle which is the same thing except a larger diameter.

The design I made was softened by packing/wrapping with fiberglass insulation mat, but didnt sound good as the perforated echo chamber that resulted without packing that sounded AWESOME (which despite the lack of packing, was a decent step down in volume from the open exhaust. The v&h sounds great with packing, so do the $50 EMGO Dunstall style mufflers of similar straight through design wife has those).






The stock mac baffle is basically just a slightly louder version of a stock bike's sound, & I am not a fan of them at all. The v&h straight through baffle is a good way to get that sound and keep a bit of back pressure, as they are not drilled so much, as they are more of a v-cut that is bent out to open a trianglular hole and then block the center through flow slightly with the tabs that are bent inwards.

[Steve]

It might have been a "competition" baffle that used to be in my son's bike.

It fell out a couple of months ago, while on the freeway, and at night.

By the time he got back to it and found it, it had been flattened like so much roadkill.

Found replacement baffles, but they are a different design, which might be what you are calling the "standard" baffle.

Not sure if the new (standard?) baffle is any quieter than the competition(?) baffle that was in there or if it just seems that way, after listening to the open pipe for a couple of weeks, but neither baffle was really bad. The original baffle was a straight-through design with a perforated tube, it looked a bit like the one you have pictured. The new one is not a straight-through design, it has one tube that pinches down and empties into the rear chamber. The exhaust then has to flow back forward, through a center baffle, to the inlet of the pipe that will let it escape out the back.

.

[huntb]

I didn'tcare for the sound of the stock baffle that came with my MAC 4 into 1 on my bike, so I made my own. It sounds like the Mac competition baffle is pretty similar to the baffle that I made for my Mac exhaust. I love the way it sounds, and got lots of comments on how good the exhaust sounded. It was much better sounding while cruising & accelerating than just an open exhaust, although the open exhaust at idle sounds thunderous and impressive compared to with any baffle in.

that exhaust is on the shelf for now until I build up a spare GS 750, and I am running a Vance & Hines, which sounds similar, and is designed similar, but smaller diameter. It has glass packing and sounds great but quieter (still quite loud). V&H also make a competition baffle which is the same thing except a larger diameter.

The design I made was softened by packing/wrapping with fiberglass insulation mat, but didnt sound good as the perforated echo chamber that resulted without packing that sounded AWESOME (which despite the lack of packing, was a decent step down in volume from the open exhaust. The v&h sounds great with packing, so do the $50 EMGO Dunstall style mufflers of similar straight through design wife has those).






The stock mac baffle is basically just a slightly louder version of a stock bike's sound, & I am not a fan of them at all. The v&h straight through baffle is a good way to get that sound and keep a bit of back pressure, as they are not drilled so much, as they are more of a v-cut that is bent out to open a trianglular hole and then block the center through flow slightly with the tabs that are bent inwards.

Nice work! I wish I had the fab skills to do something like that. I would love to hear a sound clip of it

[huntb]

It might have been a "competition" baffle that used to be in my son's bike.

It fell out a couple of months ago, while on the freeway, and at night.

By the time he got back to it and found it, it had been flattened like so much roadkill.

Found replacement baffles, but they are a different design, which might be what you are calling the "standard" baffle.

Not sure if the new (standard?) baffle is any quieter than the competition(?) baffle that was in there or if it just seems that way, after listening to the open pipe for a couple of weeks, but neither baffle was really bad. The original baffle was a straight-through design with a perforated tube, it looked a bit like the one you have pictured. The new one is not a straight-through design, it has one tube that pinches down and empties into the rear chamber. The exhaust then has to flow back forward, through a center baffle, to the inlet of the pipe that will let it escape out the back.

.

Sounds correct what you are describing Steve. See pics

Standard:


Competition:

[Steve]

Yep, that's them, exactly.

.

[Rob S.]

It fell out a couple of months ago, while on the freeway, and at night.

Competition:

The baffle from my '73 Z1 looked similar to the pic above, but with cones instead of flat plates on the ends.

And I wouldn't describe it's removal as 'falling out' - it came out as I hit redline. I retrieved it intact, but never reinstalled it.

Interesting side note: in the ten years I rode it, it was never re-jetted, even though at one point I replaced the stock air box with K&N pods, and later "removed" the exhaust baffle. Through both modifications, the bike always pulled hard to redline without a stutter.

[Chuck78]

And I wouldn't describe it's removal as 'falling out' - it came out as I hit redline. I retrieved it intact, but never reinstalled it.

That's basically EXACTLY what happened to both my baffles, both launched out like a canon at high rpm acceleration... They need a finer thread pitch bolt than what they come with, and 2 retaining bolts instead of one would also help.

My buddy behind me ran over the baffle, luckily it didnt cause him to wreck!

[rudeman]

That's basically EXACTLY what happened to both my baffles, both launched out like a canon at high rpm acceleration... They need a finer thread pitch bolt than what they come with, and 2 retaining bolts instead of one would also help.

My buddy behind me ran over the baffle, luckily it didnt cause him to wreck!

My Yoshimura only has one allen head tapped into the nut plate on the baffle and it has never been a problem. Try using Loctite next time.

[Chuck78]

the one definite way to remove a fastener that has been loctited in is to apply heat to the area, about 270 degrees or so usually breaks the loctite. I think a finer thread pitch & a good lockwasher is the only good answer. there are high temperature Loctite formulas as well, but even they have their limits with long durations of higher temperatures.

[huntb]

I just wanted to update this thread. I purchased the competition baffle from eBay and installed it. Man does it sound good! Not crazy loud like it was when open (not even close really) but has a nice deep tone to it now. Probably one of my favorite purchases so far (valve shims aren't all that cool...)

[jboge123]

I've got the Mac Competition baffle as well.. No longer sounds like a sewing machine like the stock MAC did.

I've even thought about removing the baffle for that deeper exhaust note.. may give that a shot soon.