Kawasaki ZX-10R Forum banner

1 - 20 of 35 Posts

·
Registered
Joined
·
175 Posts
Discussion Starter #1
Let me start by saying I used the search function and read all the posts regarding this. This isn't about what it does or how to remove it. It is about my impressions after disabling it. I have had my 10 for 2 years and just left the valve alone even after putting on a Leo Vince slip-on. So last weekend I started to research it again and decided since it was so easy to do why not try it and test it since it is reversible and takes about 5 minutes to do. I wasn't expecting any type of huge gain or even a noticeable difference. But I was more than suprised when I took it out afterwards to ride it. First thing is throttle response was GREATLY improved. This was the biggest thing for me. I always disliked the abruptness of the on/off throttle of the 10 especially in mid corner. Well that has been totally resolved. Next thing was the power characteristcis. I can't say I noticed any loss in low end. What I did notice was an increase in the mid-range hit. My front wheel wants to come off the ground anytime I get near that sweet spot more so than it did before. The motor also seems to rev faster. It just seems to build steam quicker so maybe that's why I didn't really notice any loss of low end. Now I am not saying that this gave me 10HP or anything. What I am saying is I think it improved the power charateristics. I do wonder if it was possible that the valve wasn't functioning properly since I saw in some of the posts that this was the case on some 10s. I know for me, its a good mod and I am keeping the valve disabled.
 

·
inappropriate
Joined
·
7,728 Posts
im going to tinker w that right now. how-to?
 

·
Registered
Joined
·
175 Posts
Discussion Starter #3
There is a thread out there with pics on how to. All I did was get to the servo, use an 8mm socket and remove the pulley that the wires connect too. No FI light that way and no issues thus far. If you don't like it after you disable it, just re-attach the wires and bolt the pulley back on. Literally took me 3 min to do.
 

·
Registered
Joined
·
34,537 Posts
Its conceivable that the cables stretch(like any) over time therfore the valve isn't functioning properly hence one possiblity why these bikes perform differently one to the next.
No doubt the disabling of the valve alters the bikes character and some may prefer it this way.

BD
 

·
Registered
Joined
·
201 Posts
I had to go try it.. (Especially since it takes five minutes to do). I felt that the engine hit earlier (about 1000 rpm sooner than it did before.) I thought that there was a little loss of low-end, but not enough to really make any difference. I'll have to go race a gixxer before I make my final analysis though. The big question is, will it cause any unnecessary damage to the bike????
 

·
Still here
Joined
·
9,059 Posts
I had to go try it.. (Especially since it takes five minutes to do). I felt that the engine hit earlier (about 1000 rpm sooner than it did before.) I thought that there was a little loss of low-end, but not enough to really make any difference. I'll have to go race a gixxer before I make my final analysis though. The big question is, will it cause any unnecessary damage to the bike????
No damage at all.
 

·
Registered
Joined
·
251 Posts
I'd like to see a dyno output comparing with valve and without. I suspect that any valve further downstream than the collector is really no more than a noise valve, for passing whatever laws exist in the customer country. I've wired the valve open on my 636, partly because it seizes up, and I can't say I've noticed any difference either way. The valve on the 2006/7 ZX10R is closer to the headers, but I'd still be surprised if there's a huge effect, but a dyno run would settle the matter.
 

·
Registered
Joined
·
494 Posts
I'd like to see a dyno output comparing with valve and without. I suspect that any valve further downstream than the collector is really no more than a noise valve, for passing whatever laws exist in the customer country. I've wired the valve open on my 636, partly because it seizes up, and I can't say I've noticed any difference either way. The valve on the 2006/7 ZX10R is closer to the headers, but I'd still be surprised if there's a huge effect, but a dyno run would settle the matter.
don't know about the 06-07 but there are many threads about this

Posted by NEK



 

·
Ex Postwhore
Joined
·
4,688 Posts
I took mine off and it's great. No complains here and its been about a month.
 

·
Registered
Joined
·
819 Posts
Alot of these things you see, exup valve, and secondary butterflies, are made to help ease the power of the bike up, and make it more manageable. If they were to build a bike that was so violent that when you let it eat, it went over backwards, all the noobs buying these things would ruin it for the rest of us. So they dummy them up and make them ridable. With the proper tuning, and removing all these it helps to wake the bike up, it by no means hurts anything. If you having a hard time believing this, think about it like this. For an internal combustion engine to perform at peak performance would you A:)stuff crap in it to slow the air flow through the motor down OR B:) Remove everything that was impeding airflow. Now there is a point where exhaust pulse comes into play, and the power curves start to change and move when you expand the I.D. of the exhaust tubing, where the air has to flow faster to start to scavenge efficiently, If done properly the power curve will move to the right on the dyno and you will pick up more top end. This works the reverse way too. This also holds true to the intake and the way it is designed, we have found power in making the velocity stacks all the same length.
 

·
Registered
Joined
·
251 Posts
When Yamaha came out with YPVS on the LC models the other manufacturers came up with very similar versions, located in the same place. Yamaha then came up with EXUP at the point where the headers collect so scavenging theory looked to be at the root of it, especially as it cuts the pipe diameter with a rotary valve that bounces waves back to the exhaust ports. But these butterfly valves in the pipe seem to lack the same logic, they are placed at different lengths from the exhaust port, so I'm not convinced there is anything but noise levels behind their existence.
 

·
Registered
Joined
·
253 Posts
If it's noise levels, why don't they just more/denser packing? Or bigger exhaust cans?

From what I understand, the Italian Twins don't have exhaust valves - and we know how awesomely loud they can be when uncorked.
 

·
Registered
Joined
·
175 Posts
Discussion Starter #14
Now that I have had more time to test, I definitely can tell a difference in power delivery and I much happier with the way the bike runs now. I also noticed an increase in noise and not just at idle. I think overall the bike is much louder. I am not sure if I like that aspect of it or not as I thought it was just fine as is with the slip-on Leo Vince but I guess thats the trade off. I am so thrilled with the smoother on/off throttle transitions now. It has made me much smoother in the corners. Did it give me any more power, I highly doubt it. I just think it improved the delivery and characteristics of the bike. I don't care why it was there in the first place. I just care about which way it is better for me and right now that looks to be without the valve operating. I wish I would've tried this sooner.
 

·
Registered
Joined
·
251 Posts
If it's noise levels, why don't they just more/denser packing? Or bigger exhaust cans?

From what I understand, the Italian Twins don't have exhaust valves - and we know how awesomely loud they can be when uncorked.
They do, this years GSXR1000 has another silencer, look at he length of some pipes. See the R6, they are sticking the silencer in the belly pan now so they can have greater volume without losing the looks. I don't know how the Italians get away with it, but who cares?
 

·
Registered
Joined
·
567 Posts
there is a difference with the motor unhooked. i noticed that the throttle reponse was very twitchy or on/off. unhooked mine today and took it for a ride and wow. the engine braking is softer and the nose doesnt dive as much or throw as much weight forward when coming off the throttle. save your self the money of a TRE and just unhook the servo. i didnt notice any difference in sound. i did notice that when i wheelie it is easier. before the throttle was hard to hold at the balance point cause it was so sensative. now it is more forgiving and easier to use. i do have a 1/5 throttle installed and keep all the slack out of the throttle adjustment. i say unhook it and enjoy the difference. i stayed away from the TRE cause i thought it defanged the beast but this seems to have just settled it a little more.
 

·
Still here
Joined
·
9,059 Posts
Can't believe I never even bothered to try this before.

I was kind of into having the valve for less sound around town at lower speeds.

Disabled it last night, only got to ride maybe two miles to the hardware store and back today and it seems great.

Just a little smoother and faster revs I guess.

Already had tre and pc.... but this seemed to help that last little bit of hesitation of the line.

Probably keep a little midrange just from the restrictive stock header anyway.

It did seem to want to lift a little easier and it may even keep me from doing the 16 tooth mod for even longer.

Gave rep to cyclops for bringing this up again and motivating me to at least try it.
 

·
inappropriate
Joined
·
7,728 Posts
heres the how-to
http://zx-10r.net/forum/showthread.php?t=6512

just disconnected mine. ill have to wait til tomorrow to ride it and throw in my 2cents. i do enjoy the throatier sound. i am a sceptic when it comes to tuning. there are a lot of people just sayin screw it and discnnecting but those who refuse to accept it stand strong behind legit and logical belief. for one, the bikes ecu was programmed to use the valve hense the extra omph when a disabled 10r was dyno'd w a pc3 over stock. also, im a street rider, i cruise around between 5-7k and am currently running a 15t front (soon jumpin to 16), with that said i dont hit up the track as i would like. so is this mod street oriented or track/twisties?
 

·
Registered
Joined
·
941 Posts
Yeah thanks for raising this back up. I'm going to do this in about an hour. I'll get back with my take on it. If I keep doing little things to make it "peppier", I might as well install wings on it and get my pilots license.
 

·
Registered
Joined
·
941 Posts
Just rode for about 2 hours with is disconnected. Seems to smooth everything a bit, as well as give it more pep. Seems louder to. No backfiring or gurgling. Getting it off is a slight pain in the nuts on the 06 though. If you don't take off the rear fairing it's real tough to get your fingers in the hole. (More than 3 unlike my ex)
 
1 - 20 of 35 Posts
Top