Topic: The Best, Smartest Exhaust Setup

[Dr. Noisewater]

Hey guys, I was hoping to get your insight on a couple things.. I'm trying to determine what kind of exhaust setup I want to go with for my build. It's a 75 550f with the factory 4-1 system. The inside of the muffler has rusted down to powder, so that's gone, but the headers seem alright.

There's a few things I have to consider.. I'm a taller dude so I'm trying to mount my rear sets as low as possible to avoid having a face full of knees. The issue here is if I mount them where they're most comfortable, in relation to my clip ons, the rear brake lever seems to interfere with most exhausts.

So considering that, I've been leaning towards an exhaust that either hangs slightly lower or ends before the foot peg (drag pipes).

My question is which exhaust setup (4-1, 4-2, or drag pipes) provides the best power output? It seems a lot of people prefer the 4-1, is that because it provides better power, a better sound, or both? Also, is it bad for the motor in any way to run drag pipes? I know it's bad if the pipes are too short, but they'd stop about where the foot peg is (MAC drags).

I'm mainly debating between the MAC slip-on muffler or the MAC drag pipes. I know I'll need to re-jet with the drags, but maybe not with the slip-on? Would there be a significant difference in power between the two setups? Is there anything else I need to consider?

Thanks for all your help.

[KJ790]

It depends on what you are going for when it comes to power output. Do you want the power to be more near the low RPM range, high RPM range, an even spread accross? When it comes to performance most people overlook the most important part, defining in their head what they want the engine to do and then building towards that. So many people just throw parts at a bike expecting it to perform better and in most cases end up hurting the overall performance because none of the parts work well together.

As far as exhaust design, the biggest factors are going to be the exhaust diameter and the length. These will affect where in the RPM range the power curve is shifted. Larger diameter, shorter pipes will tend to shift the power higher in the RPM range. Smaller diameter, longer pipes will tend to shift the power towards the lower end of the RPM range in general. It is easy to go too large of a diameter and slow the exhaust velocity too much, which will lose all useable power. Bigger is not better in most cases.

A straight through exhaust will never hurt your engine as long as your jetting is correct for the setup you are using. If the pipes are too short then you can run into problems caused by fresh air actually being sucked back into the combustion chamber due to reversion, which would cause an uncontrollable lean condition, but you have to go pretty short for this to be an issue.

In many cases, a well designed 4-1 exhaust will offer a slight performance advantage over a 4-4 setup because each pipe will now be able to use the exhaust momentum from the other cylinders to aid in scavenging. A poor collector design on a 4-1 exhaust can end up being worse than a 4-4 exhaust, so that is anothing problem, especially with some of the less expensive pipes out there that are more for looks than for performance.

Now there are a lot of people that are going to try to tell you that your exhaust needs backpressure. This is an old wives tale that has stuck around for years. Do some research and see what successful engine builders and exhaust designers say about the topic.

[Bru-tom]

^^ a good read, thanks

[Tews19]

I would keep the stock header and use a reverse megaphone exhaust from cone engineering.. You will have to rejet.

[bjbuchanan]

If I were you I would use the DCC reverse cone. I got it on sale for 42$ but it is just a regular EMGO brand reverse cone. It has a built in baffle with barely any fiberglass on it. I had bought a roll of muffler packing off ebay for 7$ and free shipping so I used that to put more packing in the cone.

It is 17" long so I think that it would work for you. It is also smaller so that you don't have to worry about it being obnoxiously large and loud/droning. I think it would be the most cost effective solution to just put on a new muffler and I think the reverse cone is great looking.

You could also go balls out and get a stainless motogp pipe and have everybody envy you but it's beauty isn't for everybody's budget.

[Tews19]

Also Chris has stopped his production on that pipe for the year... I got one of the last 5 for the year..... She looks pretty but steep price tag..

Sent from my SAMSUNG-SGH-I337 using Tapatalk 2

[Dr. Noisewater]

Awesome, thanks guys. I was really leaning towards drag pipes, but I know I'll get annoyed with the noise. Plus I'd like to get away without re-jetting it immediately.

Considering that I think I'm just gonna get the MAC 4-1 system. If the muffler gets in the way of my rear brake lever I'll just chop and weld a new piece so the muffler doesn't angle up as much. I think that's the most cost effective way to hit the road ASAP and have some fun before it snows.

Thanks for the info guys. I'll be posting the build before/after pics soon enough.

[lucky]

Awesome, thanks guys. I was really leaning towards drag pipes, but I know I'll get annoyed with the noise. Plus I'd like to get away without re-jetting it immediately.

Considering that I think I'm just gonna get the MAC 4-1 system. If the muffler gets in the way of my rear brake lever I'll just chop and weld a new piece so the muffler doesn't angle up as much. I think that's the most cost effective way to hit the road ASAP and have some fun before it snows.

Thanks for the info guys. I'll be posting the build before/after pics soon enough.

Another two solutions for you.

Use a 4 into 1 exhaust but put a cycle shack all metal baffle in the header section, THEN put on the megaphone.  That works too.


Four straight pipes like the Cycle-X Roadster Longies with 4 pine cone HD style baffles.

[Stev-o]

Awesome, thanks guys. I was really leaning towards drag pipes, but I know I'll get annoyed with the noise. Plus I'd like to get away without re-jetting it immediately.

Considering that I think I'm just gonna get the MAC 4-1 system.

The Mac is far from the best, I'd say it was the worst thatbis readily available.
Use the existing header, it is excellent.  And put a Cone Eng muff on it as Tews suggested.

My 550F came with a Mac muffler, didn't like it and sold it to a forum member.  He didn't like it either.

For the money, Carpy makes a very good pipe also.

[Tews19]

Mac is poop... had one on a bike I had... The stock headers work perfect with a reverse megaphone... Let me find a video of mine.... Cone engineering will cost 80.. mac 340 plus shipping. You will have to rejet w mac as well.