Which after-market muffler for 04 GS?

[prwatts]

Which is the recommended aftermarket muffler (slip-on) to reduce the size/weight and give it a bit more growl, and low-end response?
Do I need to replace the Cat?

Thanks Peter

 

[Mr K]

All replacement mufflers allow the stock Cat to be retained...

For my self, I have a Stainless Remus can obtained from a tosser of this parish, which is neater, louder and sexier than the stock lead dustbin.

The world is your silencer.

 

[(RIP) Miff]

Personally I like the look of the standard silencer.

I had mine cut open, gutted and welded back up.

Much cheaper than a new can. And if the police want to complain, then it's just a "standard can officer"

 

[littleredrooster]

What's a muffler? Does it keep your hands warm...?

 

[Kremmen]

I had mine cut open, gutted and welded back up.

Your reasoning is sound & the thought of doing this has indeed crossed my mind a while ago after reading that the cat had been removed in the same way.

Which end of the can was opened up & was was actually removed?

 

[Mr K]

Don't waste your money. Take the standard can off and just run it with the cat. Some of the guys run a stuby pipe to deflect the exhaust gases.

Tad fruity and torches LH pannier.

 

[Kremmen]

As i can TIG weld & have access to plant, it wont cost me a penny..

 

[Rob Farmer]

Tad fruity and torches LH pannier.

There's always some fecker quotes your post before you can delete it

I forgot the 1200 cat is much smaller than the 1150

 

[(RIP) Miff]

Your reasoning is sound & the thought of doing this has indeed crossed my mind a while ago after reading that the cat had been removed in the same way.

Which end of the can was opened up & was was actually removed?

I (ok, a mate) cut open the side of the can

The exhaust gas route is shown

He removed most of the metal inside

Welded back up and the sleeve put back over.

Someone else on here cut the end off the can and gutted it completely HERE . Goto page 2 for the can surgery.
I wish I'd had mine gutted totally, as it's still not loud enough.

 

[Kremmen]

Thanks Miff,
Over the winter i will definitely be gutting my can as per end cap removal.

 

[prwatts]

And it goes through MOT no problem?

A friend of mine had his Harley fail on noise - that sound is patented, dammit, and the turd-burglar MOT twit failed him. And once its in the computer there's no going back. We spent the morning stufffing glass wool up the zorst and holding it in place with a piece of pipe and wire. It was grudgingly accepted and we yanked it all out again. What a w@nker.

If I change my can I thought I would need to keep the OEM to get through the MOT as these guys are becoming real anal about it. Still, we are better off than the Chermans and their tests, I suppose.....

 

[peter-k]

Peter, here is Peter, too.

If you like have a look at this exhaust tests clicky, for models pre '10.

Realistically not much to expect in terms of power but heavy on lost dough. It's just appearance and weight loss, same what you are always asking your wife for

 

[GSmonkey]

Changing the can is only for noise - decat the headers if you want to affect the performance in any way.

As for the MOT, you just need the right MOT test station. My MOT tester races bikes at the weekend - nothing was even mentioned about the full Remus.

Also, go with a titanium can, much lower in maintenance than stainless.

 

[prwatts]

Thanks everyone - and does the ECU adapt to the extra air?

I have a friend who's 2004 GS dropped an exhaust valve very expensively, and upon research it was found that that same problem had happened a few times but was being kept quiet. The valve is (surprisingly to me) made in 2 pieces and friction welded where the head meets the shaft and that's where it failed. I would worry that changing the zorst makes the mixture leaner and therefore overheats the exhaust valves.

And my bike is a 2004 though I only bought it recently.
And it gets quite hot here in Arabia in summer - nice and cool now though.

 

[GSmonkey]

It seems as long as you leave the intake side unchanged ie no mods to the airbox or filter, the bike won't lean out.

The RHS valve failures appear unrelated to modifications and have been reported on allmost brand new standard machines.

 

[prwatts]

Thanks for that. I am surprised, because with my Subaru (which is my reference because they are so measurable) when you decat and change the silencer it definitely leans out.

I have fitted a K&N Air filter in place of the stock which has that silly plate with the holes in it in front of the paper element. Am I looking for trouble?

So are you saying the ECU does not adapt the mixture? I thought that was what the Lambda sensor was for?

Does a fault show on the dash when the exhaust has been changed?
Also, when the cat gets old does a fault show?

Sorry for the endless questions.

 

[Sgt Bilco]

The lamda sensor will adapt the mixture to run with a different can no worries and it will cope with a de catted system.

However, most people (who know) will tell you that when you fit a K&N along with a full de catted system, you are starting to get into Power Commander territory. I would think you will be OK as long as you keep the cat.

Nothing comes up on the dash when you change the exhaust

 

[prwatts]

Many thanks Sarge,

Presumably the best is to then keep the OEM air filter and decat the zorst, as it seems that the removal of the cat is most beneficial to the free airflow of the engine, no flat-spot etc etc.

I am quite surprised a K&N Air Filter makes so much difference.

Peter

 

[littleredrooster]

The lamda sensor will adapt the mixture to run with a different can no worries and it will cope with a de catted system.

Only at tickover. Anything above (i.e. as soon as the throttle is opened) and it follows a pre-set fuel map. It will therefore run weak if you increase the air flow through the engine.

However, most people (who know) will tell you that when you fit a K&N along with a full de catted system, you are starting to get into Power Commander territory.

Exactly. You need a Power Commander (or similar) for the reason mentioned above.

 

[Kremmen]

Only at tickover. Anything above (i.e. as soon as the throttle is opened) and it follows a pre-set fuel map.

I don't think think this statement is quite correct..
I'm sure you will find that output from the O2 sensor is used whenever the engine is running in closed loop