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Exhaust Systems

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Deleted member 213 said:
Couple of vids on You Tube on exhaust mods. One scraps the originals the other modifies them.

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The little shorty sounds beautiful to my ears. I'm looking for something not to pricey in similar size with tip ending at the edge or rear tire that rides nice and straight at the bottom. A swordfish tail would be nice as well.
 
Here is the exhaust mod I performed on my R18. I pulled the stock mufflers off and bought fish tail slip on exhaust from Freedom Performance Exhaust in California #BM00064 in the 33" around $1000 which takes it even with the back tire. Then took the head pipes off. The exhaust gaskets have tabs that hold the header nut in the correct position to align with the studs in the head. The head pipe being stainless and the slip on's being made for the factory head pipes is why I chose to go this route. vising up the mounting stud in copper jawed vise to firmly hold the head pipe I proceeded to work on the butterfly valves first by fabbing a piece of flat stock similar to a car ball joint splitter to fold back the butterfly back on itself. So the piece will clear the smaller exit pipe. I then used a long saws all blade to cut the butterfly in to. Then cut the servo spring mount off. Then cut back the shaft mounts on each side to the first weld even. The butterfly's fell out. This gives access to the catalytic converter. I used a hammer drill with a 24" x 1" bit to drill holes in the cat material as many as I could. Then fabbed up a tool using a old 1/2" drive socket welded to a 1/2" X 24" shaft with 3-1/4" bolts welded in apposing angles. Attaching it to a cordless impact I proceeded to bust up the remaining cat material fairly easily. ounce all the cat material was out I welded up the servo valve shaft holes with stainless caps. Taped off the chrome and capped each end of the head pipe. After a short time in the sand blaster the head pipes came out nicer than from the factory. this will give them the look of the engine covers. I cleaned every thing up and reinstalled the head pipes lubing the mount shafts with a little with white grease and antiseized the o2 sensors. note the pugs for the front o2 sensors are at the bottom base of the cylinders and the back ones are under the plastic cover under the bike. I purchased two servo buddys to plug in place of the servo motors #42-2757 around $120. The exhaust comes with two 8" baffles if you want to use them or add longer ones if you need a lower sound. The end result was as loud as a drag pipes on Harley Davidson. There were no codes thrown. This mod is not for everyone with just the slip on's it had a good sound with less pop and crack. Before doing any of this I consulted BMW tech and talked with all the current full no cat exhaust manufactures to make sure there would not be a need for a program tune. They all said NO and this turned out to be correct for me.
 
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moleculo said:
Then you'll really like what they sound like with the baffle drilled out. An even nicer sound without being LOUD.
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Howdy, am new here with an R18B and am very interested in giving the exhaust drill out a try (purchased the hole saw, extension bits....) , but am a bit hesitant given the one-way, no-return nature of the mod if the sound is too loud or affects the tune of the bike. I know you mentioned it's not offensive, nothing to fear, but a sound clip and your impressions of the tune changes or not would really assist (ie, did it need a Bren-tune or was this done prior to Bren-tuning and how did the engine cope - any changes through the rev range, low rev surges, anything of that nature or just a slight sound increase only ?).
(ps, I don't have the Bren-tune also thinking of it but again a bit worried about screwing it up !)
Thanks !
JD
 
JDoc12 said:
Howdy, am new here with an R18B and am very interested in giving the exhaust drill out a try (purchased the hole saw, extension bits....) , but am a bit hesitant given the one-way, no-return nature of the mod if the sound is too loud or affects the tune of the bike. I know you mentioned it's not offensive, nothing to fear, but a sound clip and your impressions of the tune changes or not would really assist (ie, did it need a Bren-tune or was this done prior to Bren-tuning and how did the engine cope - any changes through the rev range, low rev surges, anything of that nature or just a slight sound increase only ?).
(ps, I don't have the Bren-tune also thinking of it but again a bit worried about screwing it up !)
Thanks !
JD
Click to expand...
First thing to consider,$1600 each muffler to replace once you have gone down that road.
Next,There is 1 guy I heard of that drilled the mufflers and we are still waiting for a sound clip.Noise is relative and subjective.If you don't like it what is your next step in your plan.
The Bren Tune and DNA filter will give you some more grunt and sound.
Last thing,I have a Indian 116 BBK build w/headwork and many performance parts.I decieded to take off the Rinehart mufflers and try the stock oem mufflers just to see how it sounds and performs.It actually sounds nice and barks pretty good.I picked up tq on the initial 1/4 throttle/low end.
Mufflers are overrated to be sure.
If you can wait and find a set of take offs to cutup or buy a set of aftermarket mufflers.After having a loud bike the BMW is really nice with the Tune,aircleaner and black RSD end caps.Nice rumble and I did'nt destroy a pair of $3200 mufflers.
I always keep a pair of sock oem unmodified mufflers and header.

btw,there is also a unit to electronically keep the flapper valves open that will give you more volume.These work on the R18: 42-2757



https://www.amazon.com/Woodcraft-Se...7e-9dcf-fc0b8e81d215&pd_rd_i=B07F8G6L1X&psc=1

 
Great & thanks for the advice - some very true info there. Having come from a highly modded Harley, it's the combination of work - intake, exhaust, tuner / mapping, cams, etc that give the significant changes. But agree intake & tuning can give a noticeable step in running performance / throttle response. I've put the DNA filter into the stock intake setup (have noticed a slight throttle pickup improvement), and will consider the DNA frame setup if I go down the Brentune route ......
Will check out the flapper unit - does it need the Brentune mods to work properly ?
 
JDoc12 said:
Great & thanks for the advice - some very true info there. Having come from a highly modded Harley, it's the combination of work - intake, exhaust, tuner / mapping, cams, etc that give the significant changes. But agree intake & tuning can give a noticeable step in running performance / throttle response. I've put the DNA filter into the stock intake setup (have noticed a slight throttle pickup improvement), and will consider the DNA frame setup if I go down the Brentune route ......
Will check out the flapper unit - does it need the Brentune mods to work properly ?
Click to expand...
We really got lucky with the BMW because they use wideband O2 sensors on their R18 and S1000RR models.Which means the ecu has a much broader range to adjust compared to the narrow band sensors.Where the Brentune helps is shown on their dyno chart and lean cruise/midrange.
 
Yes - see what you mean quite an increase in torque on partial throttle which I suppose would give an extra dose of that ‘roll on’ pull which is where I probably do most of my riding - after reading comments here and looking at Brentunes site I’m pretty much sold on it. And it’s on discount at the moment…..
 
JDoc12 said:
Howdy, am new here with an R18B and am very interested in giving the exhaust drill out a try (purchased the hole saw, extension bits....) , but am a bit hesitant given the one-way, no-return nature of the mod if the sound is too loud or affects the tune of the bike. I know you mentioned it's not offensive, nothing to fear, but a sound clip and your impressions of the tune changes or not would really assist (ie, did it need a Bren-tune or was this done prior to Bren-tuning and how did the engine cope - any changes through the rev range, low rev surges, anything of that nature or just a slight sound increase only ?).
(ps, I don't have the Bren-tune also thinking of it but again a bit worried about screwing it up !)
Thanks !
JD
Click to expand...
My mod is not for every one and requires the ability to be able to perform the mod. I have a full machine shop at my disposal. It did exactly what I wanted to acomplesh. The sound can be regulated with different baffle lengths if needed. If you want to save your stock exhaust then get a aftermarket system or slip on. Like everything else a stock exhaust is only worth what some one is willing to pay for it regardless of what it cost new.
 
Yes can see what you mean from your description for the 1st Ed fishtails - is a complex job. Mine is the bagger version with the round muffler and was looking at member ‘Moleculo’s’ baffle disc drill out only - as you say without the right gear and experience things could go wrong. Thanks for the advice !
 
So I purchased a set of take-off fishtails and I still haven’t been able to find any pictures/videos of what was done on the mufflers that have been modified.
I know there was a forum member that had a shop in the U.K. Do his and had promised to post details but we never heard from him again.
 
twisted throttle said:
Here is the exhaust mod I performed on my R18. I pulled the stock mufflers off and bought fish tail slip on exhaust from Freedom Performance Exhaust in California #BM00064 in the 33" around $1000 which takes it even with the back tire. Then took the head pipes off. The exhaust gaskets have tabs that hold the header nut in the correct position to align with the studs in the head. The head pipe being stainless and the slip on's being made for the factory head pipes is why I chose to go this route. vising up the mounting stud in copper jawed vise to firmly hold the head pipe I proceeded to work on the butterfly valves first by fabbing a piece of flat stock similar to a car ball joint splitter to fold back the butterfly back on itself. So the piece will clear the smaller exit pipe. I then used a long saws all blade to cut the butterfly in to. Then cut the servo spring mount off. Then cut back the shaft mounts on each side to the first weld even. The butterfly's fell out. This gives access to the catalytic converter. I used a hammer drill with a 24" x 1" bit to drill holes in the cat material as many as I could. Then fabbed up a tool using a old 1/2" drive socket welded to a 1/2" X 24" shaft with 3-1/4" bolts welded in apposing angles. Attaching it to a cordless impact I proceeded to bust up the remaining cat material fairly easily. ounce all the cat material was out I welded up the servo valve shaft holes with stainless caps. Taped off the chrome and capped each end of the head pipe. After a short time in the sand blaster the head pipes came out nicer than from the factory. this will give them the look of the engine covers. I cleaned every thing up and reinstalled the head pipes lubing the mount shafts with a little with white grease and antiseized the o2 sensors. note the pugs for the front o2 sensors are at the bottom base of the cylinders and the back ones are under the plastic cover under the bike. I purchased two servo buddys to plug in place of the servo motors #42-2757 around $120. The exhaust comes with two 8" baffles if you want to use them or add longer ones if you need a lower sound. The end result was as loud as a drag pipes on Harley Davidson. There were no codes thrown. This mod is not for everyone with just the slip on's it had a good sound with less pop and crack. Before doing any of this I consulted BMW tech and talked with all the current full no cat exhaust manufactures to make sure there would not be a need for a program tune. They all said NO and this turned out to be correct for me.
Click to expand...
Thank you.
 
twisted throttle said:
My mod is not for every one and requires the ability to be able to perform the mod. I have a full machine shop at my disposal. It did exactly what I wanted to acomplesh. The sound can be regulated with different baffle lengths if needed. If you want to save your stock exhaust then get a aftermarket system or slip on. Like everything else a stock exhaust is only worth what some one is willing to pay for it regardless of what it cost new.
Click to expand...
Much simpler task than modifying the OEM fishtails.
 
MilwDave said:
Much simpler task than modifying the OEM fishtails.
Click to expand...
Not sure about that.

The flappers stay open on their own. No need to cut or remove them. The entire cat is reasonably easy to remove by cutting the header open with a grinder, pulling out the material and welding back up.

Unless I missed something, the big difference in modifying fishtails is that one ends up with fishtails. 😜
 
Gr8adv said:
Not sure about that.

The flappers stay open on their own. No need to cut or remove them. The entire cat is reasonably easy to remove by cutting the header open with a grinder, pulling out the material and welding back up.

Unless I missed something, the big difference in modifying fishtails is that one ends up with fishtails. 😜
Click to expand...
I question the need to gut that cats to get better sound. I’ve seen numerous videos of slip-ons used on bikes in Europe that have great sound. The bike builders there take the Euro regulations seriously and leave the cats intact.
 
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