[Gixxus]

Anyone tie theirs open yet? Just wondering if this might reduce the throttle snap.

 

[leenineplus]

What do you have to do to remove it?

 

[lee711]

I don't know if it works the same, but i had an exhaust flapper valve on the Tuono V4, the default position was open and this was held via a spring. The valve was opened and closed via actuator controlled cables, thus once the cables were disconnected the valve reverted to the open position, the cables were either disconnected and tucked away or removed completely, could be similar for this bike. ??

 

[Davidgorman]

Same on the Bking, disconnect it, will need a aftermarket plug for the connection to keep the ecu happy

 

[Ireek]

You probably could just remove the cables and let the little servo thingy continue to move, then maybe safety wire the valve open if the spring doesn't feel stout enough to keep it open all the time.

 

[leenineplus]

I wonder if the flapper stays in an open position the exhaust will sound a little more race like. What would be the simplest way to get the flapper to stay open in the exhaust and to then disable or disconnect the system or cables so it could not close again.

 

[daley]

I find that the flapper stay fully open when the engine running on 1000rpm

 

[Beaky]

My old K1 1000 only came into work between 3500 and 5000rpm to meet emission laws.... vw springs to mind ..... it made no difference at all when I disconnected it and was unable to tell when I ride it .

 

[landy10]

Spoken to dynotech eccosse in Glasgow about this, its only there for drive by noise emissions and seems to have nothing to do with how the engine runs as such, whether or not it would have any noticeable effect on performance is doubtfull

 

[daley]

i disconnected the cable to the valve and done a few run, find out the bike run much smooth below 5000rpm, and have a bit backfire noise. On off throttle smooth out a lot.

 

[Gixxus]

i disconnected the cable to the valve and done a few run, find out the bike run much smooth below 5000rpm, and have a bit backfire noise. On off throttle smooth out a lot.

Not supprised at all!

 

[dekker]

I disconnected the cables by removing the mounting plate at the exhaust valve and pulling them out, thus leaving the settings intact. I could not really tell much difference on a test ride, maybe a little less abrupt ?
However the upper cable is now fully retracted and won't move, and there is loads of slack in the lower one so I can't refit them. Plus the F1 light is on!
The actuating device is buried deep and looks like a lot of work to get at.
Does anyone know how to reconnect the cables?

 

[daley]

I disconnected the cables by removing the mounting plate at the exhaust valve and pulling them out, thus leaving the settings intact. I could not really tell much difference on a test ride, maybe a little less abrupt ?
However the upper cable is now fully retracted and won't move, and there is loads of slack in the lower one so I can't refit them. Plus the F1 light is on!
The actuating device is buried deep and looks like a lot of work to get at.
Does anyone know how to reconnect the cables?

you got to take out the servo, and open it up. Dont try to force it to turn, it will break the internal gear, once you got it open it a sample job to move it.

 

[Gixxus]

Seems a bit involved. My Z1000 you just disconnected the electrical connectir and applied voltage to certain pins to get the motor to move.

 

[dekker]

Thanks for the replies, have sorted it now.
It was a real pig to get at although only held in by two screws.
I applied gentle pressure to the pulley wheel and it turned ok allowing me to untangle the cables.

 

[leenineplus]

Ive taken the cables off the exhaust flapper at the exhaust end. Now has an Error F1 on the dash. It sounds louder but not brilliantly loud.


Looks like an investment in one of those electronic control boxes. Ahhhhh

 

[grisoguy]

so what's the general consensus with these exhaust valves? I'd like to believe it, but not too many people showing dyno graphs with theirs removed, and A LOT of speculation floating around.

I understand the theory is that it is supposed to improve driveability and midrange torque by keeping the exhaust velocity up yada yada scavenging etc... But I can't help but think maybe it's programmed to restrict flow a little too long. Maybe it's closed longer than it should be?

I've never owned a bike with one of these valves, but I've seen other bikes reporting improvements by disabling it. Also on earlier gsxr models, it's easy to disable by removing a wire from the ECM connector.. Any idea which wire it would be on our bikes?

 

[Joe Garfield]

When I started talking to the tune shops around here, they looked at the stock ECU map for this bike and said the timing was 'really off'. I can imagine the engineers at Suzuki playing games with timing and back pressure to try to keep the bike fun while meeting emissions regulations. Changing the exhaust valve will affect the back pressure but not do anything to compensate for the timing or fuel enrichment.