hey guys. so ive been reading up on flapper mods, PAIR valve mods, klean air mods, etc....

ive never seen anyone do these mods on an f4i. do you just not need to? are they hard, or not possible? anyone know whats up? thanks!

 

Well here's what each of them doand IMHO is it worth it? For the time, effort, and cost I don't think it would be worth it.

* the below information is someone else's explanation, I just copied and paste the info so people can know what it is.

Flapper Mod: http://www.919.org/flap.htm
Simply put, the Flapper Mod allows the flap on the R32's exhaust, which is always closed at lower revs (to let poor sleepy neighborhoods enjoy their peace and quiet), to open up while still running these lower rpms. The open exhaust flap now allows the engine to breath and roar like it does above 4,000 revs, and it also adds horsepower by reducing exhaust backpressure.

Pair Valve Mod: http://www.cbr929rr.com/pair.htm

Well, one reason is to stop backfiring on decel, another is if you plan on sealing your airbox and probably the best reason is to make it practical to correctly map your A/F ratio if you have any dyno tuning performed.

Oh, and you lose about 1.5 lbs of junk and make a very crowded area on the engine somewhat less cluttered . .

Klean Air Mod: it lets fresh air into the exhaust immediately after the exhaust valve. this helps burn unburned fuel before it goes to the cat or out the can.

 

does the F4i even have those? I know the F4 doesnt, and dont think the 01 - 03 F4i does, Cali model prolly does their EPA standards blows goats.

 

considering i did pair valve mod on my f4i, it has the pair valve
don't know about others. mine, especially is the cali model and had fuel evap too. i got rid of it(it was beaten up by previous owner pretty badly).

 

The F4i doesn't have a flapper.

 

ok thanks for the info guys. i might test out the PAIR valve mod to see if it doesnt do anything. i thought that our bikes didnt have flappers but i just wanted to double check...

 

Hey guys,

Here is a thread that shows a pretty clean PAIR valve removal proccess. It is SUPER cheap also.

https://cbrforum.com/m_512968/tm.htm

Oh, as for removing the charcoal canister, do you just plug the vacuum lines that go up to this intake that came from the canister/sensor?

Thanks,

Josh

 

ssweetbro, thats a perfect thread to show what to do. thanks!

 

i did the pair valve mod on my bike. definitely noticed an improvement in the lower half of the powerband. i couldn't see hwo putting O2 in after the combustion chamber helps to "burn" fuel before the catalytic converter whenconverters use O2 (not all isconsumed during normal combustion)toCATALYZE oxidation reactions with partially burnedhydrocarbons. if anything it would cause exhaust gas molecular weight to be lighter (less soot) and create less resistence as it is pumped out of the system. I'm not a combustion physicist/engineer but i do have a strong background in chemistry and science.

 

i ended up removing the PAIR valve, and while it doesnt seem like there is a power difference, it does seem a little smoother at lower RPMs. i also just passed emissions without a problem, so it doesnt affect the emissions system on the bike that much....