Exhaust Servo

Kickstand_Down

Kickstand_Down

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Hey all, so coming from an R9T, disabling the exhaust servo flapper was a common mod to give the stock exhaust some more grunt. I randomly saw a bit of discussion on the same thing for the R18, but I was unable to find much in the way of specifics.

It is my understanding that the same servo flap is used for most/all BMW motorcycles that have it, so I'm assuming the process for disabling it is the same?

  1. Take off plastic cover
  2. Loosen retaining nuts around cable
  3. Take cable out of groove and unseat cable end (both sides)
  4. Tuck cable ends into concave section of servo center
  5. Put plastic cover back on (servo designed to "fail open" so now will be open 100% of the time)
Has anyone done this on their R18? Seems like the biggest issue is access, but just curious if it really is exactly the same as other bikes.

Thanks!
 
Kickstand_Down said:
Hey all, so coming from an R9T, disabling the exhaust servo flapper was a common mod to give the stock exhaust some more grunt. I randomly saw a bit of discussion on the same thing for the R18, but I was unable to find much in the way of specifics.

It is my understanding that the same servo flap is used for most/all BMW motorcycles that have it, so I'm assuming the process for disabling it is the same?

  1. Take off plastic cover
  2. Loosen retaining nuts around cable
  3. Take cable out of groove and unseat cable end (both sides)
  4. Tuck cable ends into concave section of servo center
  5. Put plastic cover back on (servo designed to "fail open" so now will be open 100% of the time)
Has anyone done this on their R18? Seems like the biggest issue is access, but just curious if it really is exactly the same as other bikes.

Thanks!
Click to expand...
I'd like try this on my TC but I need someone to point me at the servo cable on the exhaust. Got a pic?
 
A pic would be great if you have time Kawasakidj. I was unaware of this mod.
 
Sure, I will be the newbie in the room. What does ‘…disabling the exhaust servo flapper’ do and can there be any done side to doing it on the base model with the balloon exhaust?

i recall a guy on YT that got a new 2022 r1250rt commenting about an exhaust flapper issue that…think he said…disabled some bikes while on the road..
 
In both downpipes, roughly under the foot pegs there is a round metal disc, that is rotated from fully open to virtually closed, by a servo motor. It’s all linked to the ECU and is there for reducing noise, altering the characteristics of the bikes performance. It’s personal choice whether you want to meddle or not. Many R9T owners have but not all. Bikes are so complicated nowadays (Euro5) I personally wouldn’t but it depends what you want and how much faff you are prepared for if the bikes start throwing up fault codes or doesn’t run too well (without aftermarket tuning). I believe some owners had trouble with them seizing up due to soot, gunk etc because they operate in such a hostile environment but that might not be such an issue nowadays as they have been used for a good few years.

This is an R9T ‘flapper’ but the R18 is no doubt similar

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Hmmm ... now you are making me curious, I have custom pipes on my FE and I have had them apart a couple of times .. I have never noticed such a choke plate ...
 
motoring said:
Sure, I will be the newbie in the room. What does ‘…disabling the exhaust servo flapper’ do and can there be any done side to doing it on the base model with the balloon exhaust?

i recall a guy on YT that got a new 2022 r1250rt commenting about an exhaust flapper issue that…think he said…disabled some bikes while on the road..
Click to expand...
Speaking from R9T experience, idle and low RPM, the valve is closed/nearly closed. It's purely a sound thing. If you disable them, you get more exhaust noise, and (don't know about R18) quite a bit of overrun pops and crackles when shifting/cutting the throttle. I know for many R9T folks who were used to the older years models, it killed a lot of the character of the bike to lose the sounds and such.

Again, personal preference, no benefit other than if you like the noise.
 
Rufus said:
In both downpipes, roughly under the foot pegs there is a round metal disc, that is rotated from fully open to virtually closed, by a servo motor. It’s all linked to the ECU and is there for reducing noise, altering the characteristics of the bikes performance. It’s personal choice whether you want to meddle or not. Many R9T owners have but not all. Bikes are so complicated nowadays (Euro5) I personally wouldn’t but it depends what you want and how much faff you are prepared for if the bikes start throwing up fault codes or doesn’t run too well (without aftermarket tuning). I believe some owners had trouble with them seizing up due to soot, gunk etc because they operate in such a hostile environment but that might not be such an issue nowadays as they have been used for a good few years.

This is an R9T ‘flapper’ but the R18 is no doubt similar

View attachment 7141View attachment 7142
Click to expand...
This is partly why you remove the cables from the valve and don't disconnect the servo itself. You will get a dash warning if it's disconnected (R9T, assume the same for R18), but nothing visual if you just undo the cables turning the flap. I have a GS-911, and it will pull a fault for the servo malfunctioning, but said fault goes away if you reconnect the cables. Sold my R9T to a dealer no worries this past Saturday with the flapper being disabled for 90% of the bike's life.
 
Question.. I bought a servo buddy, healthteck brand, noticed under the bike there are two connectors, one for each servo, do I need two servo buddies or is there another hidden connection to plug into before they split to each exhaust? Also do I plug into those connection underneath if not a hidden connection for both….if that makes any sense, thanks
 
moleculo said:
Tonight I located the flapper valve and servo but I'm still unclear on how to perform this mod without throwing error codes. Is this the correct Servo Buddy? https://www.revzilla.com/motorcycle...490a1c0e12&cjdata=MXxOfDB8WXww&sku_id=1185159

Also, does anyone have a step-by-step instruction on how to perform this mod? The Freedom Performance mufflers should be here any day and I'd like to do this at the same time.
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Yes that is the correct one but you will need two of them. I bought both mine as a pair off ebay for $70 shipped. So far I've removed the 2 servos, bracket and cables. It's just one bolt holding it all to the frame. This winter I will remove the rest of the flapper valves in both pipes and weld up the holes. Just plug the two servo buddies into the harness where the servos plugged in to and zip tie them up into the frame out the way. This is a very simple mod to do with what I've done so far. Takes about 15 min or less. Obviously removing the valves will require more time as it entales removing the exhaust(or maybe not, depending how talented you are)
I've got about a 100 miles on it so far and no issues. I notice a tiny bit more volume at idle and that's the only difference. To me it's worth it to not have to worry about more exhaust parts failing over time, especially if it fails in the closed position
 
One could maybe argue that removing them helps the engine run cooler since at idle is when usually the least amount of air is flowing through the oil cooler, and over the cyl head cooling fins. The valves closed or near closed are preventing the hot exhaust gasses from flowing out the tailpipe... therefore heating up engine, especially during long idle times in traffic. I dunno🤷🏻‍♂️
Smarter minds than me may kno 😆
 
Sessoms02 said:
Question.. I bought a servo buddy, healthteck brand, noticed under the bike there are two connectors, one for each servo, do I need two servo buddies or is there another hidden connection to plug into before they split to each exhaust? Also do I plug into those connection underneath if not a hidden connection for both….if that makes any sense, thanks
Click to expand...
You will need 2
 
So am I understanding correctly that all we really need to do to default the butterfly valve open is just unplug the circuit and plug in the servo buddies?
 
moleculo said:
So am I understanding correctly that all we really need to do to default the butterfly valve open is just unplug the circuit and plug in the servo buddies?
Click to expand...
Yes but if you leave the four cables connected I'm not sure where the servos default to (open or closed). Somebody else may know. Its probably best to also disconnect all four cables so the springs will hold the flapper valves open. Or, just remove the whole servo assenbly
 
Longshot said:
One could maybe argue that removing them helps the engine run cooler since at idle is when usually the least amount of air is flowing through the oil cooler, and over the cyl head cooling fins. The valves closed or near closed are preventing the hot exhaust gasses from flowing out the tailpipe... therefore heating up engine, especially during long idle times in traffic. I dunno🤷🏻‍♂️
Smarter minds than me may kno 😆
Click to expand...

Most of the overheat conditions reported have occurred during stop & go traffic when the valve would be closed or mostly closed. It certainly can't hurt to have the exhaust flowing freely and might have some small benefit to help with this issue.
 
I just finished installing a Dr. Jekill & Mr. Hyde exhaust system; I did see the OEM exhaust servo motors during the installation. The OEM servo motors is located behind the Voltage Regulator; I did find a picture of the OEM servo motor on eBay: (see the below pictures)

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