re-fitting muffler

[chrismckay]

I currently have the muffler off my 2012 RT1200 for cleaning, should I apply any sort of grease/sealant to the joint before I torque the exhaust back together?


Chris... ^-^

[guest2360]

No. Just make sure the joint is clean.

[David.]

The Haynes Manual recommends,
"Prior to installation, clean the exhaust clamp and lubricate the inside surface with high-temperature assembly grease. Fit the clamp over the end of the silencer front pipe."

Although there is no mention of lubricating/sealing the joint between the downpipe assembly (Exhaust flow control valve) & the silencer itself,
I do use some high-temperature grease e.g. Copper Grease, my theory being it helps future removal & doesn't compromise the seal.

[step2534]

Just a quick one since its been mentioned.

What exactly is the "Exhaust flow control valve"  I realise by its name it must control the exhaust gasses but why is it required??

It seems very exposed to elements, if it goes wrong does it have a adverse effect on bike I could imagine it would if it was stuck closed but could it be manually opened or even disconnected.

When muffler is off is there any benefit in giving it a squirt of lubricant or is it just one of them units that either works or doesn't?

[Catfunt]

I use a bit of copper grease under the clamp. I also lube the exhaust valve actuator and pulley when it starts to squeak. One other thing is to make sure the clamp lines up correctly ( it has arrows) with the muffler otherwise the centre stand doesn't hit the rubber stop squarely and clangs!

[Our Gee]

Just a quick one since its been mentioned.

What exactly is the "Exhaust flow control valve"  I realise by its name it must control the exhaust gasses but why is it required??

It seems very exposed to elements, if it goes wrong does it have a adverse effect on bike I could imagine it would if it was stuck closed but could it be manually opened or even disconnected.

Good question, and one which I have often wondered about myself. Previous RT's didn't have this "Gizmo" and worked fine. Although the Twincam does sound more fruity with the Gizmo. One "problem" it does now cause is that the "Gizmo" control box does restrict access to the Gearchange linkage for routine maintenance.

[guest2360]

I believe the valve is only there as it allowed the bike to pass EU noise limits.  Above a certain speed these don't seem to apply so the valve opens and you get a better sound.  They first appeared on the GS.  If they seize up you just end up with a quieter bike.

[David.]

What exactly is the "Exhaust flow control valve" I realise by its name it must control the exhaust gasses but why is it required?

The Exhaust flow control valve, is from what I have found, actually an Exhaust noise-control valve (EN-CV),
http://www.ukgser.com/technical/nick/Re ... 20V1.1.pdf

I believe the EN-CV may have been introduced to meet noise requirements in the US.

Exhaust valves and servo motors explained, http://www.skutr.net/exhaust-valves-and ... explained/

[David.]

I also lube the exhaust valve actuator and pulley when it starts to squeak.

A nice little video showing the EN-CV pulley & cables, https://www.youtube.com/watch?v=DXJvgpWlNFw

Before the bike is started, you can hear the ignition being switched on/off, with the ignition off the valve is closed, with the ignition on the valve moves through 90deg. to fully open.

[David.]

It seems very exposed to elements, if it goes wrong does it have a adverse effect on bike I could imagine it would if it was stuck closed but could it be manually opened or even disconnected.

Like you, I would say that is it goes wrong in the closed position, then yes, the bike is unlikely to run properly.

Disconnecting the servo motor & cables etc. & making sure that the valve is open & remains open all the time would obviously solve the problem.

Alternatively, remove the valve & fit a straight through piece of pipe, http://www.wunderlich.de/shop/en/exhaus ... mover.html

From what I have read, it sounds like (no pun intended),  the bike will run perfectly well without the valve, might even run better.

Looking at RealOEM, http://www.realoem.com/bmw/enUS/showpar ... Id=18_0836,
the Exhaust flap itself doesn't look serviceable, no spare parts listed.

[Rotorwrench]

I have an R Nine T that I removed the flapper valve on for the sole reason of cleaning up the rear end of the bike.  It has had no ill effect on performance.  With the RT and all of the tupperware, I am not concerned about removing it.  But if you want to go that route, it's perfectly fine removed.  You will get an ECU code that it is removed but no warning on the cluster.

[David.]

Interesting to hear from someone who has removed the "Flapper Valve" with no ill effects, thanks for the feedback.

I believe that the R Nine T has the same engine as a Twin Cam RT.

[Our Gee]

I like my "Flapper", so it's staying !!.

[David.]

I have an R Nine T that I removed the flapper valve on for the sole reason of cleaning up the rear end of the bike. It has had no ill effect on performance. With the RT and all of the tupperware, I am not concerned about removing it. But if you want to go that route, it's perfectly fine removed. You will get an ECU code that it is removed but no warning on the cluster.

Did removing the "Flapper Valve" make any significant difference to the exhaust note/sound.