Mods to the Stock Exhaust Can

The other exhaust mods thread seems to be all about after-market replacement options.

I would like to know if anybody has modified the stock can in any way other than removing the spark arrester, or modifying the spark arrester?

On some forum somewhere I saw where somebody drilled holes into the stock can down inside where the baffles and stuff are.

Has anybody here done anything like that? Pics?

Other options with the stock can? Anything?

Over On TT I posted up what you would need to do to de-cat the pipe, remove baffles, ect...long story short, it is not worth the effort, you need to be able to cut and weld and fab....I now use a GYTR slip on.....simple No matter what you do to the stock pipe it will be heavy and louder than any Aftermarket pipe you can buy. The OEM pipe relys on Baffles to be quiet...remove those, and it gets stupid loud....Save the OEM pipe for Dual sport rides or where you need quiet and bulletproof.

It would seem to me that by removing the butter fly valve [towards the front of the pipe] by either cutting out the entire pipe housing of the valve or going inside & cutting the axle that the blade is attached to. The two little philips screws have been spot weld to the axle & I would rather see the entire pipe clean, for a free flow of exhaust.

I know cutting the valve section of pipe would be cleaner. It would only require a slip on pipe about 3.75" long. But then a sealing weld.

Before dropping between $300 & $500 on a very noise can, I am thinking of a cheap/quieter answer. It must be the KLR still in my blood.

Just disconnecting the EXUP leaves it in the default spring loaded OPEN posistion...not sure you gain much by cutting it out...it is allot of work, been there, done that....FWIW...and you can always go back for some reason...just trying to save allot of headaches for someone...

I must do something cause I have removed the entire kit & Ka-boot-toe. The more I look at that internal hunk of junk the more I want to cut out the factory weld in pipe assembly & weld in a pure clean straight pipe.

Think I better form a table jig to ensure the same angle & slight bend to the factory calm part of the upper pipe.
Orrrrrrrr....just prefit all three pieces & spot weld the package on the bike to better the alinement. Remove spot assemble & weld it as one piece. Sound about right?

Sounds like you just need to go buy a PowerBOMB header....

As nice as that my sounds, it will cost nearly 180 USD & only go as far as the clamp on the beginning of the muffler pipe, or am I still needing to learn more about this exhuast system?

Does the power bomb header replace that length of muffler pipe that houses the offending inside thingy?

Yep, it sure does... I didnt like paying around that much for mine either but that is what is available for the bike... And it works! And it looks good!

Did you keep your stock muffler?

At this time I plan on keeping the quiet one.

& thanks much!

Like my sig says, I went with the FMF Q4 and I am pleased with the sould level of the can. Not too loud at all but simply louder than the harmonics of the top end while in the revs! I still sneak around town and such with it though, as it is pretty quiet...

PonchoV wrote:

Does the power bomb header replace that length of muffler pipe that houses the offending inside thingy?

The PowerBomb does not replace the "offending inside thingy" (AKA the EXUP valve). The EXUP is part of the muffler assembly.

mwakey wrote:

PonchoV wrote:

Does the power bomb header replace that length of muffler pipe that houses the offending inside thingy?

The PowerBomb does not replace the "offending inside thingy" (AKA the EXUP valve). The EXUP is part of the muffler assembly.

Ah ,yes, I do stand corrected! It is, indeed part of the exhaust can and not the head pipe...

Hey major thanks mwakey.

& glad we are also on the same track w/ SpaGuru.

I am going to bite the surgery bullet on the muffler's pre piping & cut out along the factor weld joints. Grind the ends down after I locate pipe that will fit both open pipes.
Would have been a thought to just cut off the "EXUP" valve/pipe area & do a slip on header.

Wonder if any fab shop guy is jumping up right now & headed into the shop to bend an extended header pipe...........if so let me know & I will do a test & write up about the advantages.

Again thanks to both riders for their feed back.
This is what this forum is all about.

Poncho, if your goal is to keep the stock exhaust and just remove the EXUP, you might be disappointed. Without any other mods, you might see a decrease in low end performance without the EXUP in place. From what I understand the EXUP valve is mainly open 90% of the time, but closes on hard acceleration to give you a little more back pressure. But I guess it would depend on your riding style. Maybe you wouldn't notice it if it wasn't there. Still seems like an awful lot of work for nothing.

I concur, it may just be a waste of time with little or no performance gains at all or possibly worse...

I have a programer on order. Will this & some air box stripping not be enough?