Flapper valve mod

[wild01]

Yep, by all means. It really is as simple as pulling off the hose that goes into the diaphragm and blocking it with a screw or bolt. But I do think it benefits from having the flap removed too as this will increase the air flow if only marginally.

[GOOSE_SP2]

Im going to have a go at this over winter break, id love a bit more noise

[mattymc]

Is the vacuum tank on the right hand side of the bike? Underneath the radiator? Just to confirm.

Thanks

Matt

[JohnD]

Did the flapper mod yesterday.... it's ace

John

[David451]

Did the flapper mod yesterday.... it's ace

John

Did you just take the pipe off or did you take all the bits out.

Also, did you try it with the pipe off first to compare the two different procedures, most folk say that both methods make no difference, if any, other than the noise.

I like noise though so I have taken off my pipe and blanked it, aint been able to ride it yet but will next week.

[JohnD]

Did the flapper mod yesterday.... it's ace

John

Did you just take the pipe off or did you take all the bits out.

Also, did you try it with the pipe off first to compare the two different procedures, most folk say that both methods make no difference, if any, other than the noise.

I like noise though so I have taken off my pipe and blanked it, aint been able to ride it yet but will next week.

I just stuck an M6 bolt in the pipe.... & yes I did compare the two - noise is definitely better with the mod done, and I reckon that the bike has a little more midrange power too.

John

[David451]

Did the flapper mod yesterday.... it's ace

John

Did you just take the pipe off or did you take all the bits out.

Also, did you try it with the pipe off first to compare the two different procedures, most folk say that both methods make no difference, if any, other than the noise.

I like noise though so I have taken off my pipe and blanked it, aint been able to ride it yet but will next week.

I just stuck an M6 bolt in the pipe.... & yes I did compare the two - noise is definitely better with the mod done, and I reckon that the bike has a little more midrange power too.

John

Looking forward to giving mine a blast on Thursday, "weather permitting", the flapper seems to be something that we dont need, and its nice for a change when its an easy fix.

[sparkysp2]

i'm doing the Pair Valve mod when my blanking plates get here from the States,supposed to give a bit more power....

[steve p]

power gains from either mod are so negligable but removing the PAIR system reduces engine clutter and a bit of weight. To benefit the small amount by the flapper mod you really need a Power Commander with a custom map as you are messing with the air flow. My bike really did run the best before i did either mod and put K&N's in, but the induction noise is nice through the snorkel. Have a look at the engine upgrades on this site and it will give you an idea of what mods go together to give a ballanced result.
http://www.revolutionuk.co.uk/

I did it on my own and cocked it up costing money to pull it back. The flapper and PAIR mods wont do any harm but could be the start of the downward spiral especially if like me you listen too much to the American forums about changing the airbox and snorkel as a "must do extra 10bhp".
The chap at the above link pointed out that these air box mods are pointless unless you get all this extra air into and out of the cylinders thus requiring porting, gas flowing and reprofiled cams. Then you need to get rid with a high flow exhaust. The stock bike has been designed as a ballanced system so if you alter any of it too much it cocks up the optimum flow, and you dont get owt for nowt.

But i would probably do it all again

Forgot to say that if you do the flapper mod you may as well take it out completely and chop out all the excess plastic indide the snorkel, it really does open it up

[JohnD]

Has anyone actually got a 'before' and 'after' dyno chart for the flapper mod?

This would be interesting to see!

John