Exhaust flap valve

gooey · Jun 17, 2019

Bought an 11 plate twin cam last week and love it to bits. I noticed it is a bit louder than my 1150. It looks like the flap valve in the exhaust is stuck open. The servo cables move when the key is turned but not the pulley. Is dumping it (the valve, not the bike!) a straightforward job or just replace it?

Malvern_Beemer · Jun 17, 2019

gooey said:
Bought an 11 plate twin cam last week and love it to bits. I noticed it is a bit louder than my 1150. It looks like the flap valve in the exhaust is stuck open. The servo cables move when the key is turned but not the pulley. Is dumping it (the valve, not the bike!) a straightforward job or just replace it?

Easy job. Motorworks do an adapter that can be used to replace the valve. No noticeable difference on my 2010 GSA without the valve.

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MrC99 · Jun 17, 2019

I think you've 4 choices:-

Do nothing. The bike will run fine with maybe a slight lack of flexibility at low revs. Many/most don't reckon there's any difference. The ECU may log a fault but it doesn't cause any fault lights.
Replace the valve - unfortunately the valve isn't replaceable and you have to change the complete collector box (& cat?)
Cut out valve section and Insert a spacer. Loads of people have chosen this route.
Try and fix it. I've done this on a '15 GSA and it's pretty simple. Disconnect the Bowden cables, take off the silencer and using a mole wrench or water pump pliers on the top very gently persuade the valve to turn. I used carb cleaner to dissolve the carbon around the valve shafts. Persevere - after 30 mins mine was turning freely and returning to the fully open position when released. Reconnect Bowden cables and test. I didn't use any lube as anything on the valve shaft will soon burn off and there's plenty of carbon floating around in there to self-lube!! If you can't fix it just leave it in the open position.

Others will probably have some other experiences.

Slipperyeel · Jun 17, 2019

I too have an 11 plate and like you I love it. I'm just wondering how you worked out that it wasn't working?

I ask because after my 1150 Adventure, i have always been surprised how 'loud' it is in comparison. I'm now wondering how I can check if the valve is working?

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MrC99 · Jun 17, 2019

If it's anything like the '15 models remove the top cover and turn on the ignition. The stepper motor will try and cycle the valve and you can see if the valve turns. If you see the Bowden cables tighten and release but nothing else happens then it's stuck. If the Bowden cables don't tighten then the stepper motor may be u/s.

Slipperyeel · Jun 17, 2019

MrC99 said:
If it's anything like the '15 models remove the top cover and turn on the ignition. The stepper motor will try and cycle the valve and you can see if the valve turns. If you see the Bowden cables tighten and release but nothing else happens then it's stuck. If the Bowden cables don't tighten then the stepper motor may be u/s.

Thanks for this

. I'll have to wait for the weekend, but I'll get into it.

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Bin Ridin · Jun 17, 2019

FWIW, the valve is sprung-loaded to the Open position...

JonnyBravo · Jun 17, 2019

gooey said:
Bought an 11 plate twin cam last week and love it to bits. I noticed it is a bit louder than my 1150. It looks like the flap valve in the exhaust is stuck open. The servo cables move when the key is turned but not the pulley. Is dumping it (the valve, not the bike!) a straightforward job or just replace it?

In the words of Kylie - Especially for you..............
https://www.ukgser.com/forums/showthread.php/455910-Flappy-Valve-replacement-link-pipe

oddshapedballs · Jun 17, 2019

https://www.ukgser.com/forums/showthread.php/352658-Exhaust-Valve-Eliminator-Tube

Good set of pics explaining.

Howard J · Jun 17, 2019

Most of them seem to get stuck eventually so are removed and replaced with the bit of pipe, you don’t need to replace the whole unit, just insert the pipe that can be purchased for about £20, exhaust is slightly louder without the flappy valve and that’s it!

Mr Anderson · Jun 17, 2019

Howz said:
Most of them seem to get stuck eventually so are removed and replaced with the bit of pipe, you don’t need to replace the whole unit, just insert the pipe that can be purchased for about £20, exhaust is slightly louder without the flappy valve and that’s it!

So when they are stuck it's in the closed position?

gooey · Jun 18, 2019

Thanks for the info - I'll try and free it off first but if no joy then it's a shopping trip to Motorworks :thumb2

Slipperyeel · Jun 18, 2019

Slipperyeel said:
Thanks for this . I'll have to wait for the weekend, but I'll get into it.

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I took a brief look this morning. Held my hands on the valve as I switched on. Sure enough I can feel things moving. I also heard a little chirp - which I've wondered about for a while - now I know what it is.

Is it possible to get some lube into it while it's still fitted - with the cover off?

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er-minio · Jun 18, 2019

Mr Anderson said:
So when they are stuck it's in the closed position?

Bike doesn't rev up.

My HP2 flappy valve used to get stuck in the closed position sometimes. You have to pull up, stop the engine and restart.
I now tend to listen to the click-click test when turning on the ignition.

Lord Snooty · Jun 18, 2019

Orreplace the headers and cat with an aftermarket set from Keihan.

MrC99 · Jun 18, 2019

Slipperyeel said:
Is it possible to get some lube into it while it's still fitted - with the cover off?

I think the bearings are sealed. The problem seems to be that crap builds up on the lower shaft between the recessed bearing and the valve, hence the use of carb cleaner to free it off while gently moving the valve. This means taking off the exhaust which is normally around a couple of minutes work as long as you've the right spanners/sockets.

Delboy777 · Jun 18, 2019

Take it off and throw it to fuck, its just a useless lump of german pig iron !

Slipperyeel · Jun 18, 2019

MrC99 said:
I think the bearings are sealed. The problem seems to be that crap builds up on the lower shaft between the recessed bearing and the valve, hence the use of carb cleaner to free it off while gently moving the valve. This means taking off the exhaust which is normally around a couple of minutes work as long as you've the right spanners/sockets.

Thanks. I've got the right tools. In my case it's all working it seems. So I'm looking to preventative measures or at least giving it a little longer before it fails... which seems inevitable.

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Bin Ridin · Jun 19, 2019

No bearings in mine, just plain bushes, open ended, so easy to squirt some oil onto. Should creep in along the spindle.

Benhur Malta · Jun 19, 2019

hi all,

assuming you want to keep the valve operational, what sort of tension do the cables have to be at? i assume that they should not be loose right?

thanks

R.

Exhaust flap valve

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