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-   -   airbox mod? (https://cbrforum.com/forum/f4i-main-forum-11/airbox-mod-8099/)

IrideHONDA 01-20-2006 09:48 PM

airbox mod?
 
i have an '02 f4i, and i know that there is a air valve on some of the other bikes that is supposed to cut down on the noise level, in order to pass inspection i assume. but, i hear that if this is removed then it will increase horsepower. so, i took off my air box and found no valve, only a small cylinder, under the air filter, that leads to another small chamber. anyway, i was wondering if anyone has modded this to increase power or just for the heck of it.

SquireSCA 01-20-2006 11:24 PM

RE: airbox mod?
 
The thing that reduces the noise are the twin resonator chambers on the ducts leading into the airbox. I am not sure what year they started doing it, but my '05 had them and so I removed them.

eteller 01-21-2006 02:18 AM

RE: airbox mod?
 
Not sure if blocking those of will add any hp or not, a question I would like to konw the answer to as well. I would think it would be a very small amount if any as Honda probably spent alot of time designing the runners on some sort of flow program as competitive as the bike market is to max out the hp to get sales. I did gather this from a previous post:


The pair reed valve introduces fresh filtered air into the exhaust ports to allow for a more complete combustion of fuel. It is located behind the center triple tree nut in the crook of the frame. Lift the fuel tank to access it. You can either pull the pair reed valve completely and replace it with a T or leave the valve in place and use it . ( I prefer the replacement method because it takes the electrical connector, which keeps the valve closed at start up, out of the loop. Although, I left the original valve in place at first and replaced it with a plumbing T a month later and noticed no difference in performance.) There are an electrical connector and three hoses. Two of these hoses go straight down to the engine valve cover and the third goes from the PRV to the air box. There is one other hose by itself and not connected to the PRV that goes from the engine valve cover to the airbox. this is the Positive Crankcase Ventilation hose. Pull this PCV hose out completely and plug the hole in the airbox. Now, the third hose from the PRV to the airbox is disconnected from the airbox end (plug the hole in the airbox) and reconnected to PCV port where the fourth hose was removed from. One more time condensed; Leave the two hoses going from the PRV down to the engine valve cover alone. Remove the PCV hose. Pull the hose going from the PRV to the air box off of the air box and re-route it to the PCV port. The hose that was going from the PCV to the air box is removed completely. This creates a crankcase scavenging system like on dragbikes and dragsters. You remember seeing hoses on dragsters going from the valve covers to the headers? Dynoed four times throughout one neutral weather day, created 3 RWHP.

DThompson 02-23-2006 04:32 AM

RE: airbox mod?
 
I wonder if your talking about the FLAPPER mod maybe.

Look in the forums for Flapper mod and I think there is one called Pair and flapper mod in a post.

Daniel thompson

Turboedsupe 02-23-2006 02:39 PM

RE: airbox mod?
 
I thought only the 1000's could do that mod?

DThompson 02-23-2006 07:45 PM

RE: airbox mod?
 
I think someone was talking about it with an F4i, I didnt do it to my bike so I dont know for sure. Sorry if I was mistaken

Daniel Thompson


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