6 into 6 Exhaust

[NickChilds61304]

Guys, New to the forum, thanks for the add. I have a 99 Valkyrie with the OEM exhaust. I have been looking for a set of 6 into 6. This is my second bike from my GL1800 being my primary ride, and my Valkyrie being my pure fun ride. I found a set but they are pretty rough. The price is extremely cheap but I am curious if anyone has had any experience with something like this with removing the rust and possibly having the headers redipped? Or is it possible to just buy new headers and keep the pipes.

Having trouble adding photos, I can send over, needless to say they are rusty headers.

[98valk]

u will lose 10hp and mpg with them.

[carolinarider09]

Guys, New to the forum, thanks for the add. I have a 99 Valkyrie with the OEM exhaust. I have been looking for a set of 6 into 6. This is my second bike from my GL1800 being my primary ride, and my Valkyrie being my pure fun ride. I found a set but they are pretty rough. The price is extremely cheap but I am curious if anyone has had any experience with something like this with removing the rust and possibly having the headers redipped? Or is it possible to just buy new headers and keep the pipes.

Having trouble adding photos, I can send over, needless to say they are rusty headers.

I had the 6 into 6 exhaust on my 2003 Valkyrie but changed them back to OEM pipes.  Mainly for noise but maybe better gas mileage.  I will see if I still have them.

[NickChilds61304]

Thanks, I would appreciate it.

[Willow]

u will lose 10hp and mpg with them.

That is misinformation and it should be stated that there are at least three different brands and types of six into six exhaust systems.

[98valk]

u will lose 10hp and mpg with them.

That is misinformation and it should be stated that there are at least three different brands and types of six into six exhaust systems.

I presume the OP was talking about the Cobras, since they are the most common.  the two brothers and the other brand all lose HP, that is what straight pipes due lose HP.
It has been well documented by many legit dynos and even by FactoryPro.com on their dyno that the cobras lose 10hp from OEM pipes.

[klb]

A friend of mine used to ride a 99 standard with Cobra exhaust with no change of jetting. My 99 standard is all stock and while riding one Saturday we inadvertently ran our bikes side by side on a four lane road. If there was a difference in horsepower between the two you couldn't tell it because it was like they were glued together. It did take my Tinnitus about a week to calm down from how loud his bike was. The inadvertently part was another friend that bashed Honda's all of the time was going to show me how much his real motorcycle a Harley Road King could outrun my bike and my friend on his Valkyrie just decided to join in. It ended up with the Harley way behind and the two Valkyrie's dead even. I prefer the stock exhaust over the Cobra exhaust but if someone likes the sound of the Cobra's I can't see the power difference if any would be that noticeable.

[Willow]

u will lose 10hp and mpg with them.

That is misinformation and it should be stated that there are at least three different brands and types of six into six exhaust systems.

I presume the OP was talking about the Cobras, since they are the most common.  the two brothers and the other brand all lose HP, that is what straight pipes due lose HP.
It has been well documented by many legit dynos and even by FactoryPro.com on their dyno that the cobras lose 10hp from OEM pipes. 

You didn't specify the Cobras, but even so it is BS based upon people who run a test with something to prove.  I have two Valks with Two Brothers', one with Cobras, and two with OEM exhausts.  I would be happy to run my bikes with straight pipes against anyone with stocks.  Oh, wait, I already have.

Do, by the way.  Not due.

Speaking of horsepower, you do know that gaining or losing seven pounds results in an increase or decrease of one horsepower at the road.

If one is worried about his horsepower there are larger factors than loud or whisper pipes to consider.

Incidentally, I've put two Interstates into the salvage yard.  Both were running whisper pipes.

What more I have to say is not allowed by the Rules.

[Chrisj CMA]

While each bike (engine) is slightly different one from another and the 97 is a tad stronger than the rest 6X6 pipes or “straight” pipes interact with the engine differently than OEM. One should evaluate how changing pipes affects YOUR bike

Honda engineered a really good stock exhaust. Each side shares the muffler can with the three cylinders on that side providing a bit of back pressure and balance. Straight pipes don’t do this

When my 97 had Straight pipes (Cobra) it ran rich until I switched to a K&N air filter. Then, it ran perfectly. I’ve never dyno’d my bike but I have since changed back to stock pipes. I still run the K&N but was ready to switch back if that was needed. It wasn’t.

I firmly believe straight pipes (Cobra or Two Brothers) without the back pressure probably rob a tiny bit of HP but hardly enough to make a tangible difference and not enough that HP loss should be a part of the decision to go with straight pipes or not.

I run OEM unmodified exhaust because I was routinely (four a year) doing 10 HR riding days and the loud exhaust was tiring. I guess I got old lol

If you run other than stock pipes you should assess how the engine is running and if need be re-jet or like in my case, a higher flow air filter was all that was needed.

The main difference is exhaust tone and volume not HP

[NickChilds61304]

Thanks for the information. Honestly, I am not concerned with HP or MPG for this bike. If I want to do a long ride, I get on the GL1800. This is just a pure recreational fun bike, and I would like the deeper sound. I appreciate all the advice. My main question was concerning replacing/repairing headers or just moving along to find another set due to cost. I will look into the Air filter solution as well while I am at it. 

[NickChilds61304]

Thats kind of the thought, the headers were pretty rough, there was even a small hole in them. I would upload pics but couldnt figure it out. I even thought about wrapping the headers in some tape but I like the chrome all over the bike and do not want to ruin the aesthetics of the bike. while it is a second bike I still like a clean looking bike.

[MAD6Gun]

 I have done several carb overhauls for customers that have Cobras. I just install bigger jets to compensate for the lack of back pressure. Go from #35 pilot to #38 and from #100 main to #105. Every customer I have done this for has had zero complaints. They all said "its never run this good". Not sure on the mileage but who cares. I personally didn't buy a Valkyrie for fuel mileage.

 Its engine building 101. Any time you take back pressure away you need to add fuel to compensate.

[f6john]

I’ve never owned a set of Cobra’s but I did have a set of Two Bros 6x6 and boy were those LOUD. In a good way but that was when my wife was still riding with me some. I eventually took them off and passsed them on to some guy in Georgia. The Valkyrie just begs for a 6x6 system and will always be music to my ears, as like my as my hearing holds out.

[98valk]

I have done several carb overhauls for customers that have Cobras. I just install bigger jets to compensate for the lack of back pressure. Go from #35 pilot to #38 and from #100 main to #105. Every customer I have done this for has had zero complaints. They all said "its never run this good". Not sure on the mileage but who cares. I personally didn't buy a Valkyrie for fuel mileage.

 Its engine building 101. Any time you take back pressure away you need to add fuel to compensate.

"Any time you take back pressure away you need to add fuel to compensate. "
that is so so wrong.

back pressure is an old proved wrong thought on exhaust systems.
it is all about the exhaust gas velocity through the exhaust port right on out to the end of the exhaust pipe. increasing the velocity lowers the back pressure, just lowering back pressure does not increase velocity.

lets make it simple; adding fuel when not needed increases low end torque and reduces upper midrange to WOT  horse power, also the torque drops off and mpg.   this is why the cobra needle kit uses pig rich needles. how many have stated they smell a lot of gas when riding behind a valkyrie with cobras and the needle kit? people have posted such on here yrs ago.

so like a harley lots of low end torque and they think its a fast bike.

HP is how fast you hit the wall, Torque is how far you move the wall.