Exhaust Swap Query....

botus said:

the idea of the noisy flap is quite sensible - setting it open during idle was a nasty childish idea - but it is in many ways is just shift cam on a budget - fit lively cams trying to get it to breathe and make serious go at the top, and lower down the revs half the air falls out the exhausts - so to compensate you have to ride it worse pushing up emissions - bung up the hole and it works better ...EXUP YPVS ATAC all the same basic idea try to keep the fuel inside where it makes a better bang rather than just a smell

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I do not see the relevance of the systems that you have mentioned YPVS was used on 2 strokes !! EXUP altered the collector volume so was close enough to the exhaust ports to effect the cam overlap, and Atac was used on the NSR500 not a plodding old boxer engine.
I still feel convinced that it was introduced for sound emissions as it was after the cat a long way from the exhaust ports..
I do not see how a valve introduced after a restrictive catalytic core could have any bearing on cam overlap.
Regards De-cat headers and stock exhaust, it is a good budget option, I have a friend who uses this , louder than stock but not as loud as my full Remus system.
Here is a photo of a couple of cat cores that I have removed in the past just to illustrate how restrictive they are.

Mistacat said:

Regards De-cat headers and stock exhaust, it is a good budget option, I have a friend who uses this , louder than stock but not as loud as my full Remus system.

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Does this Option produce better Running Chris?
Any Popping on Overrun?

There is a lot less restriction in the exhaust system with the cat core removed, it looks big in the photo but its actual size is approx. 75mm in diameter and the holes are approx. 1.2mm.
I have not noticed any popping on overrun when following my mates bike with the de-cat nor do I get any from my Remus. But we both run AF-XIED`s .

Mistacat said:

There is a lot less restriction in the exhaust system with the cat core removed, it looks big in the photo but its actual size is approx. 75mm in diameter and the holes are approx. 1.2mm.
I have not noticed any popping on overrun when following my mates bike with the de-cat nor do I get any from my Remus. But we both run AF-XIED`s .

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I run the AF-XIEDs too but my OHV Model sounded terrible with the full Akra System fitted.
That said, I didn't leave it on very long so maybe it would have sorted itself out given time.
I Test Rode a TC at Sycamore BMW and it had a full AC Schnitzer System fitted.
It was very nice.
No idea if it's been Remapped or had the Leads fitted or what.
I don't want to end up with something that annoys me on a Run and scares the local Wildlife...

Just curious how you get the cat core out. Do you have to cut the exhaust open remove and weld the exhaust back up or can you rive it out with a bar or something?

Cut the exhaust in half through the middle of the weld on the cat with a 1mm slitting disc, mark its position first.
Chain drill around the edge of the core to remove it.
TIG weld it back together as the original weld is quite large you will not be able to see that it has been tampered with.