Topic: Header question

[longshanks]

I have a Mac 4-1 system that the previous owner installed and I got to say I really don't like the sound at all. Baffle in or out, doesn't matter. I noticed the headers are not mandrel bent so my question is will I benefit that much from getting a set of headers that are mandrel bent or am I wasting money? The little knowledge that I have tells me that minor improvements in exhaust flow won't benefit too much without other major work done like head work, cam, big bore, and better carbs. I've looked into Lossa's and Carpy's 4-1's and the sound is great but I believe neither of those are mandrel bent either. What I'm thinking of doing is getting rid of the exhaust canister and buying Lossa's reverse cone muffler(looks and sound, but better performance?) until I can warrant the need for racing headers. Does my thought train seem correct? Despite all this, it seems(after pouring over the forums) that a properly flowing 4-4 aftermarket yields the best overall performance. I believe Hondaman says this in a post somewhere but I could be wrong.

Also, does anyone have youtube videos with the Lossa reverse cone installed and running? I'd love to hear it.

p.s. lets please not turn this into a flame war about which is exhaust brand is the best, blah blah... thanks!   

[MCRider]

I had a MAC and didn't like the sound either. Odd.

Several here have had luck making a different muffler. Get a chrome tip from a car parts store. Or Google "shorty motorcycle muffler" or such.

[longshanks]

What about the performance aspect I've mentioned?

[MCRider]

What about the performance aspect I've mentioned?

Well, 4-4 is what CRs ran way back when. 4-1s are what Yoshimura ran and did pretty well. Too loud. Both are what are being used on racers today.

Kerkers are probably the best with something approaching street legal sound.

Macs are probably the worst. But best price.

AS to how the pipes are bent... other mods may be more meaningful.

Been a long time since anyone did any serious Dyno testing on pipes. I say throw a dart.   

[longshanks]

What about the performance aspect I've mentioned?

Well, 4-4 is what CRs ran way back when. 4-1s are what Yoshimura ran and did pretty well. Too loud. Both are what are being used on racers today.

Kerkers are probably the best with something approaching street legal sound.

Macs are probably the worst. But best price.

AS to how the pipes are bent... other mods may be more meaningful.

Been a long time since anyone did any serious Dyno testing on pipes. I say throw a dart.   

Can I just get the headers? I'd like to pair whatever I get with the Lossa reverse cone

[TwoTired]

What performance aspect are you looking to improve peak power at or near red line?  Or, cruise power,  low end grunt, etc?
Or, is it primarily all about how it looks and sounds?

A 4 into 1 "can" improve peak power at high RPM if the pipe size (diameter) is selected carefully and the header tubes are all equal/tuned length for the engine's breathing and RPM parameters.  That same exhaust will be inefficient and actually lose power capability in the low and mid range operation.  It is why this is a popular race option.

A "crossover" 4 into 2 can improve the low and midrange RPMs.  The crossover (2&3 share a muffler -1&4 shares the other) makes each exhaust outlet have a 180 degree timing and exhaust note, while improving scavenging.  It won't make as much peak power at High RPMs as a properly designed 4 into 1.
Most 4 into 2's have 90 degree pulses as they tie together 1&2 or 3&4.  And, these don't really provide much if any performance boost, but you may like the sound they provide.  They are usually pretty cheap, too.

The 4 into 4 discounts or eliminates any scavenging aid from any other cylinder.  However, joined exhaust pulses (as in other systems) don't foul the scavenging of any cylinder, making the exhaust very straight forward to tune, and works well at pretty much all RPMs.  The drawback here, of course, is the weight of four separate exhaust systems.  But for street use, it gives good power at low, mid range, AND high RPM, but will not get the "scavenge boost " effect at RPMs where a 4 into 1 system can be "tuned" to provide benefit.

Cheers,

Edit: corrected the crossover pairing reference.

[longshanks]

What performance aspect are you looking to improve peak power at or near red line?  Or, cruise power,  low end grunt, etc?
Or, is it primarily all about how it looks and sounds?

A 4 into 1 "can" improve peak power at high RPM if the pipe size (diameter) is selected carefully and the header tubes are all equal/tuned length for the engine's breathing and RPM parameters.  That same exhaust will be inefficient and actually lose power capability in the low and mid range operation.  It is why this is a popular race option.

A "crossover" 4 into 2 can improve the low and midrange RPMs.  The crossover (1&3 share a muffler -2&4 shares the other) makes each exhaust outlet have a 180 degree timing and exhaust note, while improving scavenging.  It won't make as much peak power at High RPMs as a properly designed 4 into 1.
Most 4 into 2's have 90 degree pulses as they tie together 1&2 or 3&4.  And, these don't really provide much if any performance boost, but you may like the sound they provide.  They are usually pretty cheap, too.

The 4 into 4 discounts or eliminates any scavenging aid from any other cylinder.  However, joined exhaust pulses (as in other systems) don't foul the scavenging of any cylinder, making the exhaust very straight forward to tune, and works well at pretty much all RPMs.  The drawback here, of course, is the weight of four separate exhaust systems.  But for street use, it gives good power at low, mid range, AND high RPM, but will not get the "scavenge boost " effect at RPMs where a 4 into 1 system can be "tuned" to provide benefit.

Cheers,

Thanks for the thorough reply. I noticed you didn't bring up mandrel bends. Do they affect performance much? I'm looking for overall performance, but if I have to choose I'd think I say mid to high end power. After all, these engines are better designed to wind out than your typical harley, correct?

I was also looking at Cycle X's pipes, particularly the 4-2-1. That would give more of an "overall" power improvement yes? especially over my Mac headers?

[TwoTired]

Have you found any performance headers that aren't mandrel bent?  Even the Mac I had on a 550 was mandrel bent, even though they aren't really performance headers.

Properly tuned 4 into 1 systems are NOT going to give you a mid range boost AND a high RPM boost.  They were developed to only improve top end performance and as a result sacrifice power at every other RPM range below the tuned RPM range.  This is because the exhaust pulses from adjacent cylinders get reflected back to neighbor cylinder's exhaust ports and actually impede scavenging at RPMS other than what it was tuned for.    It is the nature of the beast (physics) that sales hype cannot overcome.

I think Cycle x is guilding the lilly to promote sales, and simply telling prospective customers what they want to hear.  The mechanism by which a 4 into 1 pipe benefits performance means that it will only benefit in the RPM range it was designed to operate within.  If it is tuned for a midrange power boost, it won't help at high RPM and vice versa.

They have all the right buzz words in the sales blurb; Equal length pipe, inner diameter " correct" (so they say), good ground clearance.  But, they seem careful to not tout any performance graphs which would (should) easily show their power or performance curve or section of the curve change that will be enhanced with their exhaust.  They do have the correct cylinder pairing (2&3 and then 1&4), but there is still going to be pulse reversion, to hinder scavenging at other than ideal RPM selection.

They make very nice promises.  I can't tell if they truly deliver from their marketing and sales strategy.  And, I'm not paying them to find out with personal testing.  That is what THEY should be doing.
Personally, I find their sales tactics shady and underhanded.  But, many seems to think that is the best way to make a buck.

It's your money to spend, though.

[Really?]

Call me weird, I like the sound and the looks of the header. 

Going around the block

[longshanks]

Ok, so based on the responses here I'll probably go with a 4-1 with a Lossa reverse cone. What are my options as far as headers other than Mac? Am I really going to see a big difference if I switch from a Mac to another brand? Kerker pipes as far as I know don't separate from the baffle so it doesn't look like an option at this point.

[ChuckG750f1]

FWIW, You should look here before you order a cone - http://www.coneeng.com/

[longshanks]

Wow. Super cheap for just a basic cone. $30?!? Custom fabs run around $100-150 according to the website. I wonder if they have a pre-built reverse cone. I'll call their number on Monday, thanks for the tip!

[coneeng]

There are mandrel bent headers and there are well made mandrel bent headers.  Don't be surprised when a super cheap header made overseas is not made to the highest standards.  The biggest issue with a cheap header is usually they have primaries that are too large and the collectors are poorly made with too large an outlet.  Many times their mufflers also poorly sized.  It is understandable from a manufacturing standpoint as they are trying to cover as many bases as possible - but it doesn't mean its right.

Many times you can replace the collector with one having a better design.  And then replace the muffler with something better sized to the bike - bear in mind muffler specs depend on the mods to the motor, the rider and what the bike is being used for.

Someone asked about premade mufflers in addition to raw cones.  You can find a current list of available parts here: http://www.coneeng.com/motorcycle_components.html  And keep a lookout for a new series of "quiet pipe" cone/reverse cone mufflers, they should be ready in May and wil offer great sound but with a more mellow voulume.

[longshanks]

If I go from a MAC muffler canister to a reverse cone slip-on, will that require a re-jet?

[lucky]

First you need to know what "mandrel bent means"

ALL of the commercially produced headers are mandrel bent.
They are not compression bends made at a muffler shop on low end equipment.

Mandrel bending machines have a snake that fits inside the tube and a screw mechanism turns and tightens and loosens inside the tube so that the tube stays round during the bending process. The snake is loosened after the tube is bent to remove the snake mandrel from the tube.

All of the headers are going to sound about the same without a muffler.
Different mufflers do have different sounds.

[longshanks]

First you need to know what "mandrel bent means"

ALL of the commercially produced headers are mandrel bent.
They are not compression bends made at a muffler shop on low end equipment.

Mandrel bending machines have a snake that fits inside the tube and a screw mechanism turns and tightens and loosens inside the tube so that the tube stays round during the bending process. The snake is loosened after the tube is bent to remove the snake mandrel from the tube.

All of the headers are going to sound about the same without a muffler.
Different mufflers do have different sounds.

Cool. I understand how mandrel bending works its just that when I was observing the bends in my muffler the inside diameter of the bend looked smaller or "squished" like you see on cheap exhausts. What about my previous question of whether or not it would require a re-jet? (Mac canister muffler vs. a reverse cone)

[PeWe]

Which type of exhaust is depending on the style of the bike and the owner. I prefer 4-1. My first 4-1 was a Russ-Collins. Looked good with nice sound but with bad ground clearance. Next time I bought a 4-1 I read a test in a bike magazine 1983 and bought a cheap Alpha 4-1 very slim and much better ground clearance (see my avatar). The best buy of 4-1 systems in that magazine were this Alpha 4-1 (probably due to the low price), Kerker and Yoshimura. I started to search for new 4-1 for some years ago, I found only Kerker which has similar style as my old RC. I searched for Yoshimura during some years when it had the right slim fit and power.

Finally it's possible to buy new replicas of Yoshi 4-1. From Japan where it had ugly sharp welds (not mandrel bent) and from CB750Cafe. The latter with coating issues. I asked my self why not stainless steel? I have had black painted 4-1 many years ago that looked ugly very quickly.
Now I've found the right thing from Lossa engineering in stainless steel! Yoshi 4-1.

4-1, 4-2 or 4-4 can all be a good choice depending on the style of the bike.
If going for a 4-1, the Yoshi replica in stainless steel is the best choice as I can see. Ground clearence, look and power.

I'm convinced that the old 4-4 systems were ment to show the English bike manifacturers that had only 2 cylinders, later 3 (Trident).