exhaust question???

[kush600]

question about my exhaust
well a while back i took my stock exhaust off and installed my own home made moto gp shorty style
basically an 8 inch tube that was shaped and moded to fit as a slip on
it was LOUUDDDDD AS HELL
anyway i was told to take it off kuz i was gonna mess up my valves because there was no back pressure
so my question is is this true, will i mess up my valves if i put it back on
i have an 05 kat 600

discuss............

[Kreylyn]

question about my exhaust
well a while back i took my stock exhaust off and installed my own home made moto gp shorty style
basically an 8 inch tube that was shaped and moded to fit as a slip on
it was LOUUDDDDD AS HELL
anyway i was told to take it off kuz i was gonna mess up my valves because there was no back pressure
so my question is is this true, will i mess up my valves if i put it back on
i have an 05 kat 600

discuss............

If there is no back pressure at all, then it is possible to cause issues such as... too hot at the valves. A shorty put on as a slip on for your header, while stupid loud and anoying to everyone else around you.... isn't nessasarily going to hurt anything permanently, but it will be enough to reduce the backpressure to cause performance issues. I would think the headers alone will give some back pressure to prevent long term dmg. It's very remotely possible, but the bigger issue would be running the bike without the headers.

It is possible to have the same look, with a short resonator chamber to make it a little less anoying bad loud, and a better sounding sport sound. Go the extra step.

Krey

[squiggy]

It is possible to have the same look, with a short resonator chamber to make it a little less anoying bad loud, and a better sounding sport sound. Go the extra step.

We had someone on here that had an existing slip-on that cut it down because of some damage. It looked like a shorty. It was done very nicely.

[GregS]

This whole "back pressure" issue is based on a misunderstanding of how internal combustion engines work. The best exhaust for power is one that actually creates a negative pressure in the header, that is what scavenges the cylinders of combusted gases and aids in pulling in the fresh fuel air mixture. The problem is that a system with those attributes is inherently loud. So you add a muffler and design it to work at a useful rpm range.
There is a lot more to all this then can be said in a short"ish" post, but that is some basics to the theory.

[Kreylyn]

This whole "back pressure" issue is based on a misunderstanding of how internal combustion engines work. The best exhaust for power is one that actually creates a negative pressure in the header, that is what scavenges the cylinders of combusted gases and aids in pulling in the fresh fuel air mixture. The problem is that a system with those attributes is inherently loud. So you add a muffler and design it to work at a useful rpm range.
There is a lot more to all this then can be said in a short"ish" post, but that is some basics to the theory.

You just said the same thing everyone else has, just choosing different words and points of the process to focus on...

"Back pressure" at the forward pulse is what allows the exhaust to create a negative pressure off pulse to scavenge the remaining exhausted gas....

Krey

[kush600]

thank u guys, im working on makin it a bit more quite as it is enoying loud
it does sound very nice and sporty, it actually sounds very much like a moto gp bike goin down the road, just too loud i guess
but the exhaust looks similar to this
http://media.photobucket.com/image/m...5/SANY0513.jpg

[Delgado]

thank u guys, im working on makin it a bit more quite as it is enoying loud
it does sound very nice and sporty, it actually sounds very much like a moto gp bike goin down the road, just too loud i guess
but the exhaust looks similar to this

http://media.photobucket.com/image/motogp%20shorty/utter05/SANY0513.jpg

This is the exact pipe that I was about to purchase but was wondering about the loudness and back pressure.Did you add a baffle to you homemade exhaust?

[barryjay]

maybe it's just me .... but that looks a bit odd.

[rockin6d]

in any engine the key is balance. you want enough exhaust velocity to get all the spent vapors out and keep all the fuel in, too little back pressure and you get raw fuel past the valve and into the exhaust pipe, to much constriction and you wont completely fill the cylinder with good fuel because some of the spent vapor is trapped inside the cylinder. either way there is a loss of performance.

Idealy you want to tune both the intake and exhaust together for the rpm range you spend most of your time in, And that gentlemen is where the art is at.

[scottynoface]

You will want a baffle. I had a moto gp style exhaust on my bike with no baffle and my ears were ringing after about five minutes.

Keep in mind that Moto GP bikes sound as good as they do because they make ridiculous amounts of power, not because they have no exhaust system. Those race systems are $$$$

[JaxKat]

They can NEVER use the excuse... I didn't hear him comming... Like a Freight Train...