After market exhaust on my old steed

[MarinPhil]

Thinking of replacing the original existing exhaust from the cat back to the muffler to an aftermarket one that comes with a straight pipe to eliminate the cat altogether. So, besides the nicer growl, without the cat i know the motor will run cooler. Question is will the bike run ok, fueling etc or will i run into problems. O2 sensor? Has anyone gone the route with direct feedback? Thanks

[AndyS]

Hi yomamma,

I would advise against the changing of the stock pipe for an aftermarket one. These bikes have always worked better with the OEM pipe and most attempts at change leave the bike with holes in the power band. Eliminating the Cat is also not the best idea. 

I don't have any problem with good aftermarket pipes, but on this bike, not so much!

 

[dirtrider]

12 hours ago, yomamma said:

Thinking of replacing the original existing exhaust from the cat back to the muffler to an aftermarket one that comes with a straight pipe to eliminate the cat altogether. So, besides the nicer growl, without the cat i know the motor will run cooler. Question is will the bike run ok, fueling etc or will i run into problems. O2 sensor? Has anyone gone the route with direct feedback? Thanks

 

 

Morning yomamma

 

I agree with Andy on the 1100/1150 boxer bikes but it sort of depends on what BMW you are working with (what BMW bike is this pertaining to?)

 

I see that you posted you ride 2006 K12GT in another thread.

[Paul De]

13 hours ago, yomamma said:

So, besides the nicer growl...

 

I realize this part of the consideration is a personal preference, but If you are considering this change on the R259 motor, I have heard a number of these motors with a louder exhaust and nicer growl were not words that comes to my mind.  IMHO, something along the line of awkward drone is more the sound I associate with a loud exhaust on this motor. 

[Rawed]

I had a Staintune on my R1150RT for about a month.  Took it off and sold the system.   The bike ran fine under all conditions but it was too loud for my liking and too raspy under hard acceleration.  Stock exhaust is less tiring to the rider and better for the neighbours.

[Miguel!]

1 hour ago, Rawed said:

 it was too loud for my liking and too raspy under hard acceleration.  Stock exhaust is less tiring to the rider and better for the neighbours.

I've found this to be true  of most after market exhaust on my other bike. Seems like this is a common comment WRT aftermarket exhaust. 

 

Miguel 

[BF204]

Hiya...

 

The previous owner put an aftermarket exhaust of the type you describe on my '99 R1100R. Sorry, not sure what brand since the badge is gone AWOL, and I don't have a pict handy. It has an O2 sensor in the pipe under the bike. I pulled the can off and re-packed it last spring, but didn't love the baffle material that I used.  It took some of the edge/sharpness out of the exhaust note, but I think it mostly disintegrated within a month. So I'll be doing a re-pack with better baffle material in the next couple weeks.   The pipe is definitely louder than stock, but I don't think its at the level of being obnoxious.  Yes, that's subjective... For example my neighbor (lady  ~60 ?) twice walked over as I was parking last summer to say how great my bike sounded... but I guess that might not have really been about the bike .  The exhaust does 'burble" and pop quite a bit when you cut the throttle (due to less back pressure I imagine).. so it does have some "character".  Anything above ~80 km/hr the wind noise overtakes the exhaust note.... so there's no ongoing annoying exhaust note (at least to me) when highway driving.  But maybe that'd be different on an RT ?

 

As for performance change, I can't tell you since haven't put the stock exhaust (which I have) back on to compare...  I thought of doing that last spring, but then looked at having to swap over the O2 sensor and figured I'd just skip that since I 'm not bothered by the sound of the aftermarket one...  I don't have any surging issue and don't have any weak spot in the power band (as far as I can tell). But maybe I should try the stock exhaust this spring for fun.. One noticeable difference is the weight.  The factory cat and exhaust is way heavier than the aftermarket one.

 

Also FWIW, the factory exhaust looks nearly new, so I think the original owner likely made the switch early on. Bike now has 99K km on it and runs great so it doesn't seem to have hurt the engine....  YMMV

 

 

[AndyS]

12 hours ago, BF204 said:

....But maybe I should try the stock exhaust this spring for fun.. One noticeable difference is the weight.  The factory cat and exhaust is way heavier than the aftermarket one....  YMMV

 

 

 

It may be heavier, but my bet is it works better. Just my opinion!

[kcteun]

The stock exhaust got a split in it, so I replaced it with a a Delkevic. I have a R1100RS, which they don't list as compatible. I ordered the longest stainless muffler for a R1150RS and it fits well. If I we're going to do it over, I would have gotten a round muffler instead of oval. It has a nice throbbing sound and with the dB killer in place it's only a bit louder than oem. There's a little popping on decel occasionally. I doubt there is any change in power. It eliminates the cat and a few pounds.

[BF204]

That looks very much like the one I have, except for mine looking less pristine.... The can on mine is round in profile. Also mine has no dB killer in it, which probably makes a significant difference in sound.

[BF204]

Just an update to this thread in case the OP comes back....  I was changing fluids etc on the bike today, so thought I'd put the stock exhaust on to try it, and then would re-pack the aftermarket one at my leisure (or maybe not even put it back on)....  I even made a vid of how it sounds before taking the aftermarket one off.....  It came off OK, but when I went to put on the stock one, I found out  why it is in such pristine condition.  It looks like part of the reason for going with aftermarket exhaust (with a small can) was to make clearance for the system cases (and their mount). It would've been done soon after the bike was new.  It looks like I'd need to lose the left side case mount (the part attached to the passenger peg) to get the huge stock exhaust on.  Also, I noticed that the left side system case is larger in volume than the right (left has no cutout for exhaust)..  The right one has a cutout where the charcoal canister would have been (if I still had one). 

 

So that's where the experiment ended.... I'm not losing the cases, so I'll re-pack and put the aftermarket exhaust back on.

 

Oh, but while I had both systems off, I did weigh them...  Stock is a whopping 22.6 lbs!  Aftermarket one is..... (drum roll pleeease)  7.0 lbs!!  That's even a bigger difference than I thought.  Stock has a lot of stainless, and the cat feels like it adds a lot of weight.

[dave_a]

A flat twin is no ducati, v-4, triumph twin or howling inline 4. But it's not an unmuffled Mazda rotary either. I have a way too loud 2 Bro's pipe. I like it when in my hooligan mood. It's awful at 80 for hours, but I'm sure it exited further back or was a more sophisticated noise reduction system it would be ok. 

[Cap]

On 4/11/2019 at 5:57 PM, MarinPhil said:

Thinking of replacing the original existing exhaust...

 

I bought an R1150GS in 2001, and put a Remus carbon-fiber exhaust pipe on it.  I liked it because the bike was black, and the pipe was black. (yes, dumb, but bikes are about feelings not logic).  What I discovered was that it made no change in performance, and just a minor change in the pitch of the exhaust note: slightly lower and less harsh.  Also, I discovered that I could touch the body of the exhaust pipe, by accident, and not get burned.  Nice.  Back then, the cost was about $800.  In retrospect, I wouldn't do that again.  That bike is long gone.

 

Since then, I have acquired a 2004 R1150RT.  It has dual spark plugs.  But it still had a tendency to minor surging, and a sharp deceleration on throttle roll-off which upset the balance when entering a curve.  So, I installed a newer injector kit, and an AF-XieD.  What a huge improvement!  Surging is gone, and the throttle response is no longer binary.  Makes the bike much more enjoyable to ride in the twisties, and much easier to ride around town.

 

So, my advice for oilhead owners looking for upgrades is to focus on the fuel management rather than exhaust.

[Craig G.]

5 hours ago, Cap said:

So, my advice for oilhead owners looking for upgrades is to focus on the fuel management rather than exhaust.

 

+1.

 

I run AF-Xied units on my LT, 1150RT, 1100S and Buell Uly (also run aftermarket exhaust on the LT and S) ... all benefited from enrichment.  

[BF204]

In case the OP (or anyone else) is curious, this is what my '99 R1100R sounds like with it's freshly re-packed aftermarket exhaust. I don't know what it is, maybe a vance and hines (?). Very similar to the one on the RS above, but with a smaller can and not nearly as purdy.

 

R1100R aftermarket exhaust audio.mp3

[TwistedTech]

that sounds pretty sweet

 

[BF204]

Thanks.. that 'notify of replies' thingy is pretty nifty. Tells me when this old thread has come back to life!    I took that exhaust off towards the end of last season... The rivets holding the can together at the front end wore their holes oval.. Fixed it a couple times with oversized rivets, but it just wasn't solid. I replaced it with an ebay silencer with a dB killer insert. Worked OK, but within a month or so the "carbon fiber" end kind of melted after a spirited ride. This spring I replaced with a different ebay generic thing, also with a dB killer insert, but this time in all stainless.... I think it's a bit louder than the audio clip I posted, but at least it's solid and hasn't melted yet... Didn't notice any performance difference.  I tried to put the stock exhaust on to try it, but I realized the reason the previous owner took it off was b/c the panier on that side is the deep kind, without the exhaust cut out... So I think he went aftermarket so the silencer sat lower.  Cheers..