[jdshalimar]

how many of you have done the flapper mod? and could you guys tell me if you noticed a difference in power...or any differences at all for that matter. im intersted in this, but havent been convinced yet!!

[bwhip]

I can't speak directly to the differences, since it had already been done to mine before I bought it. Everything I've read says that it's definitely something you should do. Here's more info, in case you haven't seen it:
http://www.rc51.org/valve.htm

[Getsome]

It does add some low/mid range.. I have it done on my blade. I would expect it will do the same on the same on the RC.

[dattaway]

Not only did I remove the flapper and its ductwork, I also removed the restrictive shims underneath the air filters, their heavy duty stainless steel firewall screens. Total weight saved was over two pounds. High rpm gain reduced front end weight by at least 400 pounds..... Go ahead and take the airbox off and look at all the stuff that isn't really needed. There's a lot that gets in the way of massive air flow just to keep the honking throttle quiet.

[HRC NICK 11]

If nothing else it gets rid of the stupid clicking popping noise every time you grap the clutch at a stop sign.

I makes a differance that is more noticable after you install a power commander.

[phobiaphobe]

Speaking of flapper mod...

Be prepared to change your air filters often. I changed mine tonight with 9800 Kilometres on the 1000rr... There was a staggering amount of crap in them. Almost clogged with dust, and I found 3 whole intact bee carcasses, 2 flys and several mosquitoes. I expected them to be a bit dirty but this was really surprising. I wonder how much performance I was losing... I'll find out tomorrow when I take her for a rip.

[dattaway]

Yep, the air intake is right above the radiator where all the sand and road crap gets slung. Riding in the rain helps to fill up this sandbox. Air filters are good.