Flapper valve mod

[David451]

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

The only problem with taking all the bits out is that it spoils the value of the bike for what benefits you actually get considering taking the pipe off is almost the same. And I know, we hear it all the time "I'll never sell my bike", and I see this all the time on other forums and folk do sell their bikes.

Its like cleaning out the garage, "I'll not ever need that" and the minute you toss it you find a need for it.

The bike has more than enough power for most of us, fit a set of nice exhausts, a power commander to take out the rough edges, get it dyno'd and enjoy it for what it is. If you want to go faster buy a Ducati if you can live with them falling to bits, or a busa.

[Bobba]

I understand what your saying but I've not seen an SP drop in value because of taking all the pipework and the flapper off?
I took them off mine and lost the flat spot that was still there after it was Dyno'd and it sound LOADS better!
It makes an OOOOOOOOOONNG noise in that mid range from the airbox and makes you rev it more

[steve p]

Quite true Bobba, i have never agreed with the keep it standard idea myself, it would be a very boring world and kill the after market industry. Myself i get a lot of enjoyment out of fiddling and modding but have also kept all the old bits, not so much to pass on if i sell the bike but to re use and sell the mods if i dont like what ive done. The standard bike is more than adequate power wise and to be honest i didnt know there was a flat spot until i read about it! The susspension is however inadequate especially for the Larger lad so that should have been my first mod rather than last!

[Strappy]

I think the thing about keeping a bike standard is that there's a perception that if a bike is modified, it's been thrashed half to death by the owner. People want to buy a standard bike and then do the mods themselves, to personalise the bike to their requirements.

Bit silly really when every bike gets a screen, K&N air filter, Power Commander and a shouty exhaust anyway.

The susspension is however inadequate especially for the Larger lad so that should have been my first mod rather than last!

How so? I certainly qualify as a larger lad (6'3" and over 17st) and I think the standard springers are excellent.

[steve p]

I think the thing about keeping a bike standard is that there's a perception that if a bike is modified, it's been thrashed half to death by the owner. People want to buy a standard bike and then do the mods themselves, to personalise the bike to their requirements.

Bit silly really when every bike gets a screen, K&N air filter, Power Commander and a shouty exhaust anyway.

The susspension is however inadequate especially for the Larger lad so that should have been my first mod rather than last!

How so? I certainly qualify as a larger lad (6'3" and over 17st) and I think the standard springers are excellent.

Each to their own Strappy, however not being a susspension expert by any means i took the advice of some specialists and my dentist and had the forks reworked by K-Tech. They fitted linear springs to my weight and better valves etc. and the front end is a dream now even over potholes whereas before my dentures were suffering. Being as i replaced the rear shock as well the benefit may be spread but it is better.

If you're happy with it stay with it mate.

[SP2rider]

Disconnected the hose and plugged the diaphragm years ago and it improved the throttle action making it smoother in the bottom to mid range but no power gain. I m currently trying to get 20kg of weight out of the bike so saving every gram counts as its no mean feat and every gram saved counts towards my 20 kg weight loss target. To help save weight I totally removed the flapper, solenoid, vacum tank and hoses and saved if I remember rightly 270 grams in total so no real weight saving unless your being totally extreme like me and no pwer gains to be had but saying that it is a worth while mode in my opinion as it smoothes the throttle action and its free. My advice would be just disconnect the hose and plug the dipahragm 95% of the gains for 5% of the effort.