Gutting the exhaust

[MrWasabi]

Well ive been doing some research on an exhaust for the bike (05 636) and at the moment i couldn't fork out that kinda cash for an exhaust.
Did some more reading and ive seen some people gut the stock exhaust to get the tone they want. Basically they keep the baffle in as it also acts like a heat shield and protects the outer casing from excessive heat, but they remove the maze of chambers within the muffler.

Seen the inside of it and in theory it all sounds like a moderate job, although id need to get it welded up again and im not sure if welding stainless steel is any different to your normal metal.
But has anyone done this before? will i need to get the thing dyno'd after ive done it? will it lose all of its bottom end due to the lack of back pressure?

Thanks

[Wattie]

it may loose a little bottom end, but only the same as a slip on would.

no dyno just for a slip-on.

[MrWasabi]

Thanks Wattie

K next question, ive seen some mods where they cut down all the walls and tubes so they are left with 3 tubes in the middle.
Would it be worth just gutting the whole thing out.

For a reference here is the stock exhaust.

[swingarm]

I wouldn't bother, you'll get negligible *if* any sound increase and may create a flat spot i your acceleration..

[MrWasabi]

I've seen some vids of it done and the sound is definately not negligible. Sounds pretty much like a slip on, and if I leave the exhaust valve in it will be somewhat quieter than a slip on under 6k but after that it will roar as expected.

Still tossing up that option, but the difference between stock and debaffled, from what I've seen is not negligible. At a total cost of $5 for a cutting disk, $50 for an oem exhaust and a case of beer for someone to weld it back up, it's better than stock

[swingarm]

cant wait to hear the results then

[MrWasabi]

here ya go




He has other vids of it outside, sounds a lot better and less like a lion in a tin can

[robracer]

go the POV exhaust.
Owen I am sure me mate Scott can weld it up for you( he used to do stainless balustrades for a living & is a wizz at all fabrication) we could use my spare send it up the central coast for welding & your bike wont be off the road for more than a few hours when you change them over

[Wattie]

I've seen some vids of it done and the sound is definately not negligible. Sounds pretty much like a slip on, and if I leave the exhaust valve in it will be somewhat quieter than a slip on under 6k but after that it will roar as expected.

done assume that valve just pops open at 6000rpm...

if its anything like them 10, it opens shuts and does all weird stuff. not just open and shut at certain revs. its not like the timing retarder on the bigger bikes.

[tim]

interesting..... anyone know if it can be done to an 07 08 stocker for more volume? I Have access to a spare stocker hey Glen

[MrWasabi]

Rob we'll have a chat about that mate

Tim, in my seaching I've found that the internals of the 05-06 are the same as the 07-08. Ie same chambers and setup exept for the dual outlets on the back. So you should be able to do the same

In fact I found more on the 07-08 than for the other

wattie, thanks for pointing that out, so far all the info I've been able to find, albeit not much, on what the valve doe is that it stays semi shut low end to give torque and opens up higher in the rev range, but like you said it may be doing other things that I haven't read up on

[Gazza]

Dude ill weld it up for you and you only have to take it to wetherill park

Stainless is a peice of cake

[robracer]

Problem solved then

[mike-s]

A nice change in tone then. not a massive change either, just a "little bit" more

[Vukie]

interested to see how this turns out