Exhaust flap valve widget

[Roymondo]

Does anyone know if the exhaust flap thingy is supposed to move through its full range of movement at switch-on? I've already had mine replaced (valve and servo motor) under warranty because it wasn't moving at all, but now I've noticed that its not moving fully - i.e. when it turns clockwise at switch-on, I can turn it a bit further by hand (to a point where it meets a definite 'stop').


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I am here: http://maps.google.com/maps?ll=52.253325,-1.152282

 

[NLC]

Had the same thing happen to me. It's easy to open up and see if the spring is moving fully. A good shot of ACF50 should do the trick or some ACF50 grease. Mine failed as the spring mechanism rusted and then caused the servo to burn out. If it's still under warranty why not just take it to the dealer. Eventually, as happened to me, the bike will fail to start and will mimic a dead battery.

 

[The smudger]

It does 2 things, it increases/reduces torque by causing/removing a restriction, and it helps with the old Decibel level thingy, i.e. makes it quieter so there is no real rhyme or reason as to when/how much it moves

Dont jet wash straight at it, they dont like that....

 

[GADGET]

Have removed mine, dont see the point of it, extra weight and something else to go wrong.

 

[Schtum]

Have removed mine, dont see the point of it, extra weight and something else to go wrong.

Have you noticed any difference in performance? It should (just like the EXUP valve that it is) help with gas speed at low revs and therefore assist cylinder filling. I always thought that was one of the reasons that the DOHC engine feels much stronger at the bottom end....

 

[2 wheel humvee]

Have you noticed any difference in performance? It should (just like the EXUP valve that it is) help with gas speed at low revs and therefore assist cylinder filling. I always thought that was one of the reasons that the DOHC engine feels much stronger at the bottom end....

So, the more efficient valve train,extra cam, increased compression ratio and improved combustion count for nought and it's the widget that develops the extra 5 ponies over the previous version ?
I say the widget is there only for noise control/enhanced acoustics

 

[Schtum]

I say the widget is there only for noise control/enhanced acoustics

I don't think so. It's bound to help gas speed at low revs and therefore, cylinder scavenging. I'm not suggesting that it's completely responsible but I suspect it plays a part in the twin cam's bottom-end torque. I doubt that it provides and benefit at higher revs and hence it doesn't assist the increase in peak horsepower.

 

[GADGET]

Difficult to assess difference as have fitted remus headers and MM exhaust can, I`m happy with it, I dont think I would notice the 5 BHP extra anyway

 

[2 wheel humvee]

I don't think so. It's bound to help gas speed at low revs and therefore, cylinder scavenging. I'm not suggesting that it's completely responsible but I suspect it plays a part in the twin cam's bottom-end torque. I doubt that it provides and benefit at higher revs and hence it doesn't assist the increase in peak horsepower.

Sounds plausible that it may boost low end torque as you suggest, I do know that when following a twin cam through tight and twisty roads on my 5hp less 09 model the twin cam always got the initial jump out of the corners-no matter what gear I was in or how keenly I tried to reverse the tables, further up the rev range things evened out-though my bike is (was) equipped with de-cat remus headers.

 

[Wapping]

Some bods disconnect the valve on their HP2Sports, with apparently no ill effect. There again, that engine makes proper power, married to s sensibly light chassis.... not the weedy / overly porky GS variety

 

[APE]

Some bods disconnect the valve on their HP2Sports, with apparently no ill effect. There again, that engine makes proper power, married to s sensibly light chassis.... not the weedy / overly porky GS variety

I suspect your average HP2 Sports rider doesn't spend too much time at lower revs. What's the perceived benefit of disconnecting the widget ?

 

[NLC]

Some bods disconnect the valve on their HP2Sports, with apparently no ill effect. There again, that engine makes proper power, married to s sensibly light chassis.... not the weedy / overly porky GS variety

What about the porky HP2Sports riders?

 

[Wapping]

What's the perceived benefit of disconnecting the widget ?

Feck knows

I suspect it may well be a 'Because you can' mod. The racing HP2 Sports ran a totally different exhaust system. There again, they also ran a conventional forks set-up and a different clutch, too.

I'm still surprised nobody (in the endless pursuit of power, for power's sake) hasn't yet slapped a 'Sport' engine into a GS frame, rather like the old 7/11 and 6/9 chops that used to be the fashion in sports bikes.

 

[NLC]

Or you could do this...

<iframe width="560" height="315" src="http://www.youtube.com/embed/8XvjVvFdMIY" frameborder="0" allowfullscreen></iframe>

 

[Old Den]

Flap valve. For anybody interested.
Spent the best part of a day in Mid wales back to back testing with the valve as standard and fully open.
Conclusions.
Open, bike was slightly better in town trafic at slow speeds. Probably due to less engine braking and less switchy throttle. Medium speed A/B roads rolling on/off throttle felt less torque and I was waiting very slightly for mid range pick up.
Standard, bike better mid range but prefered it open in traffic and very slow riding (walking speed).
How do I have it? Allround I prefer it standard.
My advise ,before you chop it out ,spend some time riding your bike critically doing back to backs.
cheers Den

 

[APE]

As the current bike has been designed to run with the widget I would have thought it makes sense to leave it well alone unless you find it particularly offensive. Must admit mine has started to squeak on start up so it's going in next week for its first warranty claim

 

[Schtum]

Flap valve. For anybody interested.
Spent the best part of a day in Mid wales back to back testing with the valve as standard and fully open.
Conclusions.
Open, bike was slightly better in town trafic at slow speeds. Probably due to less engine braking and less switchy throttle. Medium speed A/B roads rolling on/off throttle felt less torque and I was waiting very slightly for mid range pick up.
Standard, bike better mid range but prefered it open in traffic and very slow riding (walking speed).
How do I have it? Allround I prefer it standard.
My advise ,before you chop it out ,spend some time riding your bike critically doing back to backs.
cheers Den

Interesting - thanks for that OD.

 

[BD]

the widget put me off the new bike,5bhp? i thought fitting a full remus to an 06 gsa gave you that over the standard,anyway it did work on an exup only at low revs as is said by causing the back pressure thing(ever ran round in a car with a shot exhaust,crap at low revs)going back to the "is it fully working",is there not a setup like on the exup to see if the servo/cables are operating fully and so opening the "widget". 4mm dowl pin and a 10mm spanner did the exup.

 

[BD]

As the current bike has been designed to run with the widget I would have thought it makes sense to leave it well alone unless you find it particularly offensive. Must admit mine has started to squeak on start up so it's going in next week for its first warranty claim

the old exup also use to do this,as the valve was iron and use to rust if left, a cure was grafite grease i think

 

[Roymondo]

the widget put me off the new bike,5bhp? i thought fitting a full remus to an 06 gsa gave you that over the standard,anyway it did work on an exup only at low revs as is said by causing the back pressure thing(ever ran round in a car with a shot exhaust,crap at low revs)going back to the "is it fully working",is there not a setup like on the exup to see if the servo/cables are operating fully and so opening the "widget". 4mm dowl pin and a 10mm spanner did the exup.

As others have said, the widget is not responsible for the extra few BHP at the top end, but it does appear to help the mid-range grunt. Indeed, the reason I whipped the cover off to check mine was working properly was because I had noticed a slight lack of oomph when overtaking at medium revs just lately. This was exactly what I had noticed when the OE valve seized up completely a couple of months ago. This time around it seems I have caught it in time - I have vigorously worked it through its full range of movement and squibbed a little ACF50 on the spring and now find that the servo motor easily turns it all the way at power-up.

If it seizes up again then it'll be back to the dealer for another new valve. I'm not going to disconnect it because, for me, it does noticeably improve the engine response.


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