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Mac Performance 4 into 2 exhaust system???

  • Thread starter Thread starter Anonymous
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I have looked into the Mac Performance 4 into 2 system for my '81 GS850G but have not gotten much good info from them yet & no images. The $300 price is awful attractive but I am cynical by nature and it sounds too good to be true.

Has someone here taken the plunge & care to offer feedback???
Thank you,
DH :)
 
Re: Mac Performance 4 into 2 exhaust system???

I have a friend with a mac 4 into 1 on his 650 and he's very happy with it.
Its fairly quiet (quieter than the V&H) and he did not have to rejet for it, so it appears to be very close to stock flow.

Earl

quote="suzukizone"]I have looked into the Mac Performance 4 into 2 system for my '81 GS850G but have not gotten much good info from them yet & no images. The $300 price is awful attractive but I am cynical by nature and it sounds too good to be true.

Has someone here taken the plunge & care to offer feedback???
Thank you,
DH :)[/quote]
 
I had a Mac 4 into 1 in a 84' KZ550 and didn't have to rejet. It was a good quality pipe, not too loud and didn't give much if any of a performance increase but it sounded and looked good and you can't beat the price.
 
you guys that didn't rejet are probably running lean...but still running enough to keep the engine going.

might be running hotter then normal.

~Adam
 
one of the illinois 550 guys has a mac 4 to 2 exhaust. i don't beleive he rejeted, it has a diffrent sound then normal but it's cool and seems sturdy enough. i have a mac 4 into 1 on mine and i am very happy with it, if you run the standard baffel then you don't need to rejet, but i chose to go with the 1.5" competion baffel. i was installing a jet kit any way.
mac is a solid product.

ryan
 
I installed a Mac 4 into 2 on my GFs 650GL. First of all, the chrome is blistering on the header pipes. Secondly, the header pipes on the right side of the bike were not bent to the proper angles so installing was a little bit of a pain. I would say that they are okay if it weren't for the chrome blistering, but that may just be the set we have.
BTW, I didn't rejet and the bike is still running rich. That's another story.
 
I had a MAC exhaust on my '80 GS850L, many years ago. It worked fine without rejetting. I had a black system which required the ocasional touch up with exhaust manifold paint as the black coating would peel & blister, but it looked good.
(Better than chrome peeling!)
 
Negative on that, I know how the plugs on my friends 650 with the mac 4 into1 pipe are burning and they's aint lean. :-)

Earl


AOD said:
you guys that didn't rejet are probably running lean...but still running enough to keep the engine going.

might be running hotter then normal.

~Adam
Click to expand...
 
earlfor said:
Negative on that, I know how the plugs on my friends 650 with the mac 4 into1 pipe are burning and they's aint lean. :-)

Earl


AOD said:
you guys that didn't rejet are probably running lean...but still running enough to keep the engine going.

might be running hotter then normal.

~Adam
Click to expand...
Click to expand...
this is something that we should clear up. As far as most poster have written, the Mac is not a performance exhaust. I believe that they even state in thier adds that re jetting is not necessary. My yammy has a mack 2 into one and pods but with the mack the exhaust we did not have to change anything and the plugs are tan. From what i understand, they are cosmetic and also good for a mild sound change.
I for one would love lots of comments based on actual tuning experiences please.
 
You are correct Scotty. Mac advertises that a jetting change is not needed with their pipes. They are intended as a (same) replacement for stock exhausts. The tell you there will not be a performance increase with their pipe and their pipes are nearly as quiet as a stock pipe. I only have experience with one mac pipe installation and it was a bolt it on 15 minute job and forget it.


Earl


slopoke said:
this is something that we should clear up. As far as most poster have written, the Mac is not a performance exhaust. I believe that they even state in thier adds that re jetting is not necessary. My yammy has a mack 2 into one and pods but with the mack the exhaust we did not have to change anything and the plugs are tan. From what i understand, they are cosmetic and also good for a mild sound change.
I for one would love lots of comments based on actual tuning experiences please.
Click to expand...
 
I had a set of mac 4 to 2 slip-ons that used my stock headers on my 77 550. The were considerably louder than stock, and had a distinct. As far as performance, my gas mileage did increase slightly. I think they had a better flow rate than the stock exhaust.
 
a mac exhaust is a direct fit without jetting if you go with there basic baffel
baf-p82t.jpg
but you can upgrade baffels to a competion baffel which comes in 1.5" or 2" and this is just a straight pipe with holes punched in it with fiberglass around it
bafp82um.jpg


a mac 4 into 1 without a baffel or one with competion baffel would need to have the carbs rejeted since you are signifigently allowing more exaust gas to escape and decreacing the back pressure. a mac exhaust is a simple design and is nothing more then a 3.5" free flow header with some sort of restrictor (that is interchangable) that bolts to the end of it (the baffel)

the mac 2 into 1 is ment for oem replacement and no jeting is required, i do not believe it doe not have a interchangeable baffel and it relies on pipe size and flow to provide the proper back presure so no jeting is required.

http://www.macprod.orc.ca/

-ryan
 
I cropped the inner tube off my mac baffel and drilled our some extra holes in thr round end piece that was left and no change except for sound. I ran it with no baffl at all and again no change in plug color but only in sound. Im wondering if Ryan((firstimer)) actually did the mac exhaust experiment or is he just speculating as to what obviously should happn when changing to a hedder?? :)
My 1100e had a mack 4 into1 and with either the baffel in or out, the only change was with the sound. This is what led me to a true hedder and other mods to accomodate it. This is what I was looking for and always look for. Other folks do things for thier own reasons as we all know. :D
 
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