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HOW TO: Dissable or Remove Air Intake Flapper Valve from Most New Honda Sportbikes
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HOW TO: Dissable or Remove Air Intake Flapper Valve from Most New Honda Sportbikes - March 3, 2006, 09:23 AM

This type of Flapper valve can be found on most new Honda sportbikes.
The marketing propaganda says the intake flapper valve is there to increase low rpm intake velocity & improve throttle response. This theory is very sound, but inside sources from Honda has released the real reason is for noise abatement testing. It seems getting an engine to pass EPA emissions testing is easy nowadays, but getting them to pass the noise level testing has been difficult at best & many times the induction noise is actually louder than the exhaust noise.


So they slap one of these flapper valves in place that only works with the bike in gear, the clutch engaged & a sufficient load on the motor so NO you cannot rev the bike & try to watch the flap open & close...

Anyway, even though I haven't seen a dyno test on the new 1000RR (yet), i have seen tests on the RC51 & the 919 & on both bikes the mid-range horsepower was increased slightly (usually 1-2 hp) with no perceivable loss of throttle response at low speeds/low rpms.

At low speeds the flapper door completely closes off & forces the engine to breathe through 2 tiny little air flaps that open as the main ram-air flapper door closes (one piece of plastic does it all). They say this increases intake velocity for better peformance, but once you try this mod you will know that is all BS.
When the bike is breathing through the 2 small openings it is bringing in nothing but hot air from the engine bay.
How to do it

The mod is soooo simple!

From the left hand side of the bike you can see the flapper diaphragm valve with the vacuum hose connected to it. Simply reach in & remove the hose then plug it with a screw or golf tee or anything that will seal up the hose & prevent it from sucking air in. Then tuck the hose out of the way where it won't get hung up on anything. Once you have removed the hose the diaphragm valve will be stuck in the open position keeping the flapper door propped open at all times

You can also simply disconnect the electrical connection to the solenoid & the flap will always remain open, but you have to remove the side fairings to get to this connection.
If you remove all the parts associated with the flapper valve keep in mind that there will be one vacuum hose left that runs back to the throttle bodies. That hose MUST be blocked off or the engine will suck in air & run poorly.

This is the simplest mod you can possibly do & if you don't like it then just reattach the hose & you're back to stock.


E_M_A_G_D_N_I_M

Last edited by fictionnn; March 3, 2006 at 10:01 AM..
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March 3, 2006, 09:35 AM

Can we get a mod to enlarge that a little?? I can not read the whole thing.


God Speed Jeff! You'll never be forgotten.

BOOSTZX3 : in all seriousness head injuries ain't no joke. I've had around 10 concussions and now I ride a Buell Don't let it happen to you!
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March 3, 2006, 10:02 AM

Quote:
Originally Posted by JohnnySpeed954
Can we get a mod to enlarge that a little?? I can not read the whole thing.
Done. You happy now old man???


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