Open Exhaust

[klev7789]

First off...yes i know that there's 100's of other posts already discussing this. The only trouble with that is that they contradict each other. Some people say its safe just the way it is, others say dont do it at all, and some say just re-jet it.  I want to settle this one for myself because I really like the sound of the open pipe and want to do it.

Also...a possible solution to back pressure would to be to construct some sort a loop or bend in the exhaust.  I race karts, and there's all sorts of different pipes. They're all wide open, but some of the best ones have a 360* loop in them, they call those torque tubes, and the other good ones have a sharp bend in them, they call those candy canes.  How do you guys feel about that creating backpressure?

[Big Rich]

First off, don't do it. It's loud and obnoxious, doesn't improve performance (you lose power off the top end), and you feed a stereotype. Loud pipes don't save lives, they risk rights.

"If" you do run open pipes, you will need to rejet. Feel free to try the original jets, but either plug chop the bike before and after, or better yet find a dyno and do a couple runs.

[skirecs]

my bike is loud, too loud for me but i don't want to spend any money to fix it since i paid so little for it in the first place and its a beat up 89
but people do turn to look, and that makes me feel a little safer

another guy on campus has a bike so quiet that i can't even hear it 30 feet away as he is going by, like a bicycle

[ben2go]

The GS has a 180 degree firing order.This makes the engine way louder than you think with an open exhaust,and then couple that with a 1200 rpm idle,it sucks.I tried it.It does kill top end a little.There is no way getting around a rejet with any exhaust mod.No rejet equals burnt exhaust valves.Another issue is pipe length,anything shorter than about 14 inches will also cause burnt valves.You really need to think this thru before you chop your exhaust.

[Fry]

Ben hit it right on the head with his reply, leave your exhaust alone or by a dedicated performace exhaust.

And it seems your after 2 distinctly different things here.

1st you say you like the sound of Open Headers, then you start talking about "Trq. Tubes" and how it seems to boost performace on shifter carts, short length headers won't improve performace that much if at all, and the U-Bends or Spaghetti creations will negate your shorties sound, 2 different things here.

Trust me, I'm about to find out all about how creating your own exhaust system, without serious exhaust theory knowledge or resources will muck things up.

[eero]

I wouldn't go open exhaust. You can still buy an exhaust that is loud and noticeable if that is what you are going for. Personally, I'd rather have a loud and obnoxious exhaust than a quiet one. Being noticed because of an obnoxiously loud exhaust is better than not being noticed at all. 

[Twism86]

Ever notice how you cant hear the loudest of bikes when they are behind you? You CANNOT hear a bike until its next to you or in front of you. Loud pipes dont help since drivers that you are approaching or coming up from behind still wont hear you. Proper riding and taking caution is 100% more effective.

Yes you will need to rejet if you go this route however. ANYTHING that changes intake or exhaust on a carb bike requires a rejet or at least some change. There are a few slip ons that people dont rejet and its ok but rejetting will always give you better performance. I would find a nice aftermarket pipe that gives you a nice low sound. 

[eero]

I agree that safe riding is definitely more effective, however your statement of not being able to hear motorcyclists behind you is false. Maybe if someone is playing their music loud with their windows up yes. But when I drive, I can hear harleys, and inline 4's coming from behind me while they are accelerating. But then again, i dont drive a turbo diesel truck. Safe riding is the more obvious suggestion. 

[twelvepoint]

Noting beats seeing a "Loud Pipes Save Lives" sticker on some guy's brain bucket helmet.

[Twism86]

Noting beats seeing a "Loud Pipes Save Lives" sticker on some guy's brain bucket helmet.

Most people do drive with music and windows up so its hard to hear anything. I personally always drive with my music blasting full bore! Im lucky to hear a cop coming up behind me 

[eero]

Speaking of exhausts..
Anyone see the video of the gs500 with the WACS exhaust on youtube? Sounds awesome, not sure if they sell them outside of brazil or not though. I'm looking at getting a loud exhaust, but not liking the skinny look of the V&H. I know there is the Jardine, and Yoshi..but they don't seem all that loud. Looking around 300-450$ range.

[ben2go]

Please take heed when those that are more experienced with this stuff try to help you.

I have the right side muffler off of a Suzuki Hayabusa aftermarket D&D exhaust.It is a straight flow through design and is loud as h377,even standing next to it.I have roughly $30 in this exhaust and I bought the GS header,D&D muffler,and had a reducer made to fit the header to the muffler.I bought the GS header because I used my factory exhaust on one of my other bikes.

My header.No amount of cleaning and painting is gonna stop the rust from coming back.It takes a serious exhaust coating to keep away rust.


Muffler to header adapter welded on.


Busa D&D right side muffler.


Look ma!I can see me boot through this thing.

[Fry]

I wouldn't go open exhaust. You can still buy an exhaust that is loud and noticeable if that is what you are going for. Personally, I'd rather have a loud and obnoxious exhaust than a quiet one. Being noticed because of an obnoxiously loud exhaust is better than not being noticed at all. 

MYTH

[jeffdodge]

I wouldn't go open exhaust. You can still buy an exhaust that is loud and noticeable if that is what you are going for. Personally, I'd rather have a loud and obnoxious exhaust than a quiet one. Being noticed because of an obnoxiously loud exhaust is better than not being noticed at all. 

MYTH

Agreed. Someone may want to run you over for having to listen to that. In my opinion (take this for what it is) its better to ride like your invisible, and expect them not to notice you.

[tb0lt]

FYI... "back pressure" is not needed for a four stroke parallel twin or most 4 strokes in general. People foolishly associate lack of "back pressure" to burnt valves or loss in power because they don't consider the whole picture AND most folks don't bother or just can't get the air fuel ratio correct after going to an open exhaust or a free flow exhaust. An open/free flow exhaust makes the flow characteristics of the engine VERY VERY different from a restricted exhaust and it is not always easy to dial in the correct jet settings. Loss of back pressure is never the issue... lack of understanding or not compensating for the radically changed air flow characteristics (and therefore AFR) is the culprit.

[ben2go]

FYI... "back pressure" is not needed for a four stroke parallel twin or most 4 strokes in general. People foolishly associate lack of "back pressure" to burnt valves or loss in power because they don't consider the whole picture AND most folks don't bother or just can't get the air fuel ratio correct after going to an open exhaust or a free flow exhaust. An open/free flow exhaust makes the flow characteristics of the engine VERY VERY different from a restricted exhaust and it is not always easy to dial in the correct jet settings. Loss of back pressure is never the issue... lack of understanding or not compensating for the radically changed air flow characteristics (and therefore AFR) is the culprit.

I agree.A lot of people are told to run 150 jets with a flow through exhaust,but my bike didn't like that.I ended up on 142.5/40 jets.With some set ups is just not possible to say what will happen to the flow and AFR.

[DoD#i]

my bike is loud, too loud for me but i don't want to spend any money to fix it since i paid so little for it in the first place

<-----------Cheap, easy fix, at least if you have a drilled out stock muffler. In my case it was beyond drilled out, and ran like crap before I did this. Highly adjustable, so long as you eat soup once in a while if you want to adjust downwards. Soup can, hose clamp, nail.

Once painted, it's less noticable.

[skirecs]

FYI... "back pressure" is not needed for a four stroke parallel twin or most 4 strokes in general. People foolishly associate lack of "back pressure" to burnt valves or loss in power because they don't consider the whole picture AND most folks don't bother or just can't get the air fuel ratio correct after going to an open exhaust or a free flow exhaust. An open/free flow exhaust makes the flow characteristics of the engine VERY VERY different from a restricted exhaust and it is not always easy to dial in the correct jet settings. Loss of back pressure is never the issue... lack of understanding or not compensating for the radically changed air flow characteristics (and therefore AFR) is the culprit.

I agree.A lot of people are told to run 150 jets with a flow through exhaust,but my bike didn't like that.I ended up on 142.5/40 jets.With some set ups is just not possible to say what will happen to the flow and AFR.

I got 150s, they were way to rich, went down to 140s as well