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Discussion Starter #1 (Edited)
Hi,

I've been having some problems with set valve. To this day I thought it's called exup - I mean this little thing on the right side of the bike, under the tank.


Anyway, occasionally (rarely though) I get the Fi error (changes with coolant temperature) and warning light is on. All I have to do is turn off and on the bike and the error is gone. So far whenever I turned on the ignition I've heard and seen this little engine moving. My friend whom I bought the bike from told me that he had some issues with it as well, that sometimes it didn't move.

So my other friend who also has the same bike tells me to jut get rid of it (remove or lock it at fully open and disconnet a wire) and that there is little if any difference. But I've read that removing it may cause the bike to loose some power at low rpm range.

What do you recommend? Remove it or replace it? And if replace - is it difficult to set it correctly again?
 

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First, have you put your bike into dealer mode to pull the codes your bike is throwing? Whenever you turn the bike off it clears any of the FI codes that were present. The FI light has to be on (as well as the bike) in order to pull the codes.
 

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Discussion Starter #3
Well no, I didn't even think about it. I'll do it the next time the FI light comes up but I'm pretty sure it's the valve, because the last time the previous owner had this problem the valve didn't move at startup and the bike run like it had less power. That's why I'm curious whether remove or repair it.

PS. I can turn off the engine with a killswitch but keep the ignition on to read the codes, right?
 

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Just leave it on when you put it in dealer mode. It very well may be the valve actuator, but it's still important to verify.



A lot of people recommend removing it, but it's really up to you about whether or not you replace or remove. Search the forum and you may find some useful information regarding this topic :thumbup
 

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Discussion Starter #5
Will do :) I'll update the next time the FI light comes up and let you know what's the code.

In the meantime I'll read about it but if anyone reading this thread has removed / repaired the set valve please let me know how did it turn out for you.
 

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I bought my K5 Liter with the entire valve itself deleted out of the midpipe, and has a Yoshi carbon muffler- no spark arrestor.
I did see that the mechanism that had the cables is still under the seat.
I have no codes, and if it limits low end power, that's OK with me (I don't thnk it does btw), cause this thing is a beast!
Having a Z bomb TRE seems to help also.

Have you done a search on unhooking it?

Good luck
 

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I would lubricate your cables and go through the procedure to properly set the cable tension, as is outlined in the Factory Service manual. Then, as the others have said, put your bike in dealer mode without shutting it off and check the code to see if it is the exhaust valve.
 

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Discussion Starter #10
I've read about it and I'm a bit confused. Do I need to remove only that moving mechanism under the seat and connect Servo Buddy/cut the cable ? Or is there something more to do?
 

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Some completely remove it, others only disconnect the cables and secure them somewhere in the bike. The purpose for the servo buddy is so that the system will not throw that FI code.
 

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PS. I can turn off the engine with a killswitch but keep the ignition on to read the codes, right?
That won't work, as the killswitch will power off the ECU. You could stall the engine, if stopping it is absolutely necessary.

I would lubricate your cables and go through the procedure to properly set the cable tension, as is outlined in the Factory Service manual. Then, as the others have said, put your bike in dealer mode without shutting it off and check the code to see if it is the exhaust valve.
+1 to that and also cleaning before lubing wouldn't hurt either. Also cleaning the valve itself (as opposed to the pictured actuator) might also help. In any case, the fact that the fault is intermittent, does suggest a dirt buildup issue.
 

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I've read about it and I'm a bit confused. Do I need to remove only that moving mechanism under the seat and connect Servo Buddy/cut the cable ? Or is there something more to do?
I don't see why you would remove it until you have confirmed it is the actual problem. And even then, I'd still attempt to clean it and set it properly, and replace the servo, before entirely removing it. It does help you by increasing pressure in order to alleviate the torque dip around 3,000-4,000 RPM, so it is not exactly to your benefit to remove it.
Mine was giving me issues and I was actually going to fix it, until I finally bit the bullet and bought a full exhaust.
 

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I've read about it and I'm a bit confused. Do I need to remove only that moving mechanism under the seat and connect Servo Buddy/cut the cable ? Or is there something more to do?
Remove the cables but keep the electrical connectors connected. Then remove the pin 34 from the ECU connector - page 4 http://www.yoshimura-rd.com/images/111526(2,5,7).pdf

It does help you by increasing pressure in order to alleviate the torque dip around 3,000-4,000 RPM, so it is not exactly to your benefit to remove it.
By removing the set valve you get rid of the dips it causes. :)
 

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Remove the cables but keep the electrical connectors connected. Then remove the pin 34 from the ECU connector - page 4 http://www.yoshimura-rd.com/images/111526(2,5,7).pdf



By removing the set valve you get rid of the dips it causes. :)
I cannot currently find it, but there was a magazine that did dyno testing with the stock exhaust with the servo disabled and with it functional, and it showed that disabling it in the fully-open position increased the dip.
That dyno just looks like an increase in power with an identical dip, and I do not know what they actually did in that dyno testing.
 

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I cannot currently find it, but there was a magazine that did dyno testing with the stock exhaust with the servo disabled and with it functional, and it showed that disabling it in the fully-open position increased the dip.
That dyno just looks like an increase in power with an identical dip, and I do not know what they actually did in that dyno testing.
In any case, it doesn't make any difference because you're not using such low rpms anyway. At least you shouldn't lol
 

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Discussion Starter #17 (Edited)
Ok I think I finally get it now :) I will start with checking the code the next time FI flashes.

If it's it I'll try lubricating the cables and setting the tension as well as cleaning the valve itself. If that fails I'll just do what -JK750- said and remove the cables (but leave the servo as it is) and remove the right cable from ECU.

The only two things I need to ask in order to fully understand how it works are:

  1. If I unhook the cables going from the servo motor under the seat to the valve do I need do do something to leave it fully open or it'll just snap open and stay there?
  2. If I find a cheap servo motor do I need to do something complicated after installing the new one? I mean is it difficult to set the cables right?
Sorry for all the noob questions but I have this stupid thing that I need to know exactly how something works before I attempt to mess with it.
 

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As best I know, the valve is spring loaded open. So it should be OK if you remove the cables. This would also give you the opportunity to check that it moves freely from open to closed. I seem to recall that others have used wire to make sure that it stayed open. But I think that is unnecessary.

Adjusting the cables is somewhat complicated. Essentially the entire chapter 6 of the service manual deals with the EXCVA. Also see 4-54 to 4-59.

There used to be information about removing the EXCVA here. But all I get now is a blank page. It was mainly for K1/K2 but had some notes about K3/K4. His method of cutting the wires to the motor and shorting them together was poor form IMO. Using a connector as a shorting plug seemed a better way.

It's also possible to remove the cables and leave the servo motor in place. Then install a rotation limiter in place of the servo pulley.

This is the K5/K6 part but I think that there's also a K3/K4 part - or this also works there.
 

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OK Bill,
Now you got me going to look under my seat at how mine has been left, etc.
I remember seeing it recently dong other maintenance work, and know my valve is gone from the mid pipe, just not sure what the ydid to the servo thingy.

As you may know, I was suprised, FWIW
The Aprilia V4 has a similar exhaust valve that is plainly seen on the Right lowerpart of the bike.
 

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In any case, it doesn't make any difference because you're not using such low rpms anyway. At least you shouldn't lol
I mean, last I checked, one spends most of one's time at those RPM on a street bike. I don't see any reason to be using a higher RPM than necessary on a liter bike, simply because you make so much power even at lower RPM. Hence my statement that it is detrimental to remove it.
 
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