the flapper mod took me 30 seconds to do.

What you should do next is go in and remove all that makes up the flapper and shave you a couple of pounds then you'll be even happier

what is the flapper mod.i own a rc51 2004 and heard of some tool on ebay to remove that.

disconnecting the vacuum hose and plug it. google it for more details.

what is the flapper mod.i own a rc51 2004 and heard of some tool on ebay to remove that.

The flapper valve is an intake noise control device.
It blocks off halve of the air intake between 5-7K RPM.
It also causes a dip in the power band between that RPM range.
By disabling the flapper valve, you not only get a better power spread, but reduce the bike's weight when all that junk is removed.

The flapper valve is an intake noise control device.
It blocks off halve of the air intake between 5-7K RPM.
It also causes a dip in the power band between that RPM range.
By disabling the flapper valve, you not only get a better power spread, but reduce the bike's weight when all that junk is removed.

thanks for info subsailor.