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Intake Flapper

2.5K views 9 replies 4 participants last post by  GligorovDimce  
#1 ·
Can someone explain to me how the intake flappers work? When I have the bike idling in neutral it looks like the doors are open. Does the bike have to be in gear with a load on them to start to close? I have searched the forums, and the net and cant find the answer Im looking for.
Thanks!!
 
#4 ·
Wow. Maybe somebody unplug the vacuum hose.
I have an 08.
They are closed on idle.
If i was you, i would completly remove them, vacuum hoses,chambers,intake flapper doors,springs and vacuum reservoir and plug the main vacuum hose.
Cleaner look and much better air flow and deep throaty sound on acceleration.
 
#9 ·
+1

Most of the Hondas (im sure other brands) have these little control units for emissions or gas mileage etc. but as long as your state does not require it and you intend on doing some upgrades, yank it.

Next to the weird vacuum version my RVF400 has, the RC51 "flapper" was the most ridiculous version I ever worked on.
 
#6 ·
If they look open on idle someone removed them

the 08+ they stay in the closed position if you remove just the vacuum hose, which is why you need to remove them and not jsut pull the hose like the previous models
 
#7 ·
They still has the springs and the actuators attached so I'm not sure. I pulled the springs and unhooked the actuators. How far open do the flaps stay? I can tell they stay open a little more than they were but they don't lay flat.
 
#8 ·
If the springs are of they will be down, but can be push upwards while driving you should pull them out