Kawasaki Sportsbike Riders Club - Australia - Online Forum

My G1 has resonators on the air intakes. My Factory Pro jet kit instructed me to remove the fresh air valve and just join up the two inlet hoses to seal the system in order to give a better midrange. There hasn't been any ill effects. You just plug the vacuum lines coming from 2 & 3 and the hose from the airbox, then join the two hoses leading into the head.

Yep, thats the go. My 9 has modified air ducts, basically remove the resonators and tape up the holes making them straight thru. The clean air intake into the exhaust valves on the top of the head cover has also been removed and a single tube runs between the 2 plates. The hole in the air box that the other end runs to has been blocked.

A bit of reasearch shows that this resonator is actually quite common in cars etc. and the purpose is to lower the noise at some frequency. It's like blowing air on the tip of the bottle and as this sound is bounced back off-phase it lowers the noise.

Some ppl also suggested that the resonator acts like a capacitor (if you're into EE you'll know what I'm talking about) which smoothens the air ripple when sucked in thus more smooth flow of air.

Now, in the case of Kwaka, there are opinions that they are actually put there by engineers to "tone" the noise of the bike. Thus the "sweetness". I've been told that the hondas for example .. cannot make this sound. Just flat.

Mine are off now but haven't got the time to ride yet this morning. I can't be bothered taking off the tank etc so I just removed the ones dangling off the intake passage. As so happens the farmland milk bottle caps fits perfectly to cover the hole (and it's red too... )

Yankee wrote:Java,

"what they all said" for starters. Then my question to you is: when do you get the loudest "induction roar"? mine tends to be at about 6000 rpm in 1st...... not too high in rev range that engine blocks it out and not too low for it not to be even kicked in and not enough wind noise yet to block it either..... is yours the same? does sound sweet though!

cheers,
Yankee

The same. Aroung 5000-6000 ish and WOT hard.

MadKaw wrote:Yep, thats the go. My 9 has modified air ducts, basically remove the resonators and tape up the holes making them straight thru. The clean air intake into the exhaust valves on the top of the head cover has also been removed and a single tube runs between the 2 plates. The hole in the air box that the other end runs to has been blocked.

Did that improve your induction noise? Louder engine = bigger grins.

Rode to Williamstown this arvo. Happy to say that YES the roar is noticeably louder. It is really nice sound! It is not deafening loud though so no earplugs are needed and I think it's only worth doing if one use the stock exhaust.

My only complaint would be missing that "sweet whirr" of the original configuration. Also I notice now that the original setup produce somewhat a multi-toned sound. The new roar is bit "mono". It's like comparing classical music with a pop one or maybe I'm just growing old...

i'm liking all the diagrams (makes it easy on us non-literal ppl).....
anyway, so what is the conclusion??!!! not just sound-wise, but also mid-range-wise??!!!
is it BETTER??? i do have a stock pipe as well..... and i do love the current induction, er, um, "roar"... but like you, LOUDER would be SWEETER!!

Yeah I like it better.... the sound.

Midrange wise I do feel more rush but this could be just false feeling due to more noise.

The whole process was worth it for me, especially taking off those things are not easy without removing fairings. All I did was remove the 4 screws holding the intake assembly and by using a very short screwdriver unscrew the 1 bolt that holds the resonator. Took me a good 2 hours ...

Cool, so basically junk the two resonators (circled in the diagram) and just plug the holes?

Mine will soon be in the dustbin

make sure you plug the holes where you took the resinators out..

I think you kill alot of the air ram affect, and would prob create abit of an odd suction sound due to the holes being open.. And you would kill alot of the pressurisation of the air ducts.

Did the mod to my J1 this weekend, resonators and now sitting in the shed never to be used again

Plug the holes with some plastic sheet that I cut and then super-glued into place (those suckers aren't going anywhere).

Definatly makes a difference to the sound, not too loud, just louder

hhhmmmmm......
sounds good (pun intended!) so, about 2ish hours NovaCoder??
also, could you get pics if not too troublesome?

cheers

Yankee wrote:hhhmmmmm......
sounds good (pun intended!) so, about 2ish hours NovaCoder??
also, could you get pics if not too troublesome?

cheers

I did it as part of the service because it's easier if the side fairings are off but you don't have to. If you were just doing it from a fully assembled bike, 2 hours will be cool, prob less. You need to slide the front faring forward to gain access to the resonators (no need to take it off though). Just take out the 3 screws either side of the front fairing and take out the ones underneath, then loosen/remove the bolts around the clocks and the whole thing should slid forward enough for you to waggle the resonators out.

I don't think you can even see the plugged holes when you get the fairings back on, I'll verify that though.

icebreaker wrote:make sure you plug the holes where you took the resinators out..

Milk caps did the job well. The snug and I just put a bit of UHU glue to it... And they are red as well...