ZX12R secondary butterflys

Thinking about removing the secondary throttle butterflys on my 2006 12R.

I've been told its a good mod.

Has anyone else done it, and are there any side affects? (except more rapid tyre wear )

Prolly be good for top end but id dare say youll lose a bit down low, someone correct me if im wrong

If you can find secondary butterflies in a ZX12 you are a first....

From what I understand ZX12's dont have the same secondry butterfly's as the ZX14, but I could be corrected..

There can be a small flat spot with a full system, that would give the impression of a staggered power curve, like secondry butterflies kicking in? do you have a full system?

I have the 2000 ZX12 and definitely no secondary butterflies....

Attachments

zx12 injectors.jpg (197.96 KiB) Viewed 3846 times

Last edited by Che on Mon Nov 26, 2007 12:11 pm, edited 1 time in total.

maybe he needs a TRE thingymajig?

Well just a power commander and a good remap, one tooth down on the front, better filter and a pipe will do it....

I have the 2000 ZX12 and definitely no secondary butterflies....

none on my 2001 Zx12R..............

Apparently there are secondary butterflys on the 06 12R. A guy I know took his out, (he has an 05 model) and he said it makes the throttle response sharper. I was told the same thing by the guys at Kawasaki at Acacia Ridge.
I guess I just wanted to hear from someone who had done, it to find out of any long term side affects.

The bike is stock & I can't afford a power commander, muffler, etc right now. I thought a mod like that would be a free bonus.

Apparently there are secondary butterflys on the 06 12R. A guy I know took his out, (he has an 05 model) and he said it makes the throttle response sharper. I was told the same thing by the guys at Kawasaki at Acacia Ridge.
I guess I just wanted to hear from someone who had done, it to find out of any long term side affects.

The bike is stock & I can't afford a power commander, muffler, etc right now. I thought a mod like that would be a free bonus.

I've been waiting for Gos to spot this one because he did it on his '05 and was happy with the results, but he would be able to give you more info on how much of a difference it made. In the meantime see if you can find anything he put up about it on the forum using the search.

[MFP to Gosling1, are you there Gos?]

From what I understand ZX12's dont have the same secondry butterfly's as the ZX14, but I could be corrected....

You may consider yourself corrected ....

.......MFP to Gosling1, are you there Gos?........

SEE YA LATER Goose !! (jumps on Z1000, fishtails out of carpark.......aaahhh gotta love a Zed !)

Secondary butterflies are fitted to ZX12R's, as far as I know from the 2004 model onward. The early models (A) did not have secondary butterflies fitted, and this is one of the supposed *upgrades* to the B models

The secondary butterflies are controlled by the ECU, and do not fully open untill 7,000rpm under standard operating conditions. They are barely cracked open at idle, and even at 5k, are only open a tad !

They present a large restriction to air-flow past the primary butterflies (located in the same position as the early 12's). But its not all bad news - on stock motors, the secondary butterflies actually smooth out the throttle response quite a bit, and help the motor respond well down low, without any 'hiccups'.....

The bad news is that for throttle-jockeys, the restriction means that you don't actually get a Wide Open Throttle (WOT) position until 7k and above. On the highway, this is a bit above normal highway speeds (we all observe posted limits don't we...)

I removed the secondary butterflies on the MFP12 before the ride to the WSB earlier this year. The difference on the highway is phenomenal - you get *instant* response and a huge surge of power anywhere above 4k.

But like anyything, you do trade away some things to get this great response at all highway speeds above 4k.........

There is a bit of a flat spot down low, which is worse when the motor is cold - the secondary throttle butterflies act like a 'choke', and allow a normal motor to pull away cleanly when not warm - This *is not* how these motors respond with the secondary butterflies removed....but the mid-to-high end response justifies taking them off !!!!

*NOTE* - If you do intend to remove these, be really careful. One false move, and you *could* see a small set-screw dissapear into the head !!!! Use a magnetic screwdriver, and stay off the piss for a couple of nights beforehand !! Its literally a 15-minute job, you can see the secondary butterflies inside the inlet tracts easily, and there are 2 screws per butterfly.

I have often considered putting mine back on for normal riding (ie commuting), and just removing them for track-days and long trips like the WSB ride etc. The better throttle response around town is worth having them stay where Kawasaki put them.

They are also fitted to ZZR1400's as well.

Since they have a stonking mid-range and top end anyway, I might leave mine on !

This mod improves mid-range and top-end response heaps - and its free !! Its worth trying the mod out, just to see how much better the response is ......the difference is substantial

but I bet once I put them back on, they will last 5 minutes before I rip them out again .....

As the 12 still amazes me when I go play, as it is in stock form, I might just save that one until I get a bit boored with it.

Thanks for the help guys.

no worries - if you do get around to doing it, to access the throttle intakes, you need to remove those large square fittings that sit just behind the air filters. Once these are removed, you can see straight down the intakes. The secondary butterflies will be right in front of you.