How to fix choices....

UDRider

UDRider

FLCL?
So exhaust valve went on my bike. Replacing it will be $$$. Dealer also said o2 sensors are disconnected. I see them connected so will need to follow up if I bring it in. Also rolling from throttle, even a little bit, and rpms going from above 4k, to below 4k just slams you forward. Latter was like this from a start.


So choice A. Bring it to dealer, fix the valve, see what's up with sensors, and the throttle issue will remain. Although if O2 sensors are borked maybe it will be fixed.

Choice B. Sent ECU to get mapped by Rexxer. They will put map that's always in open loop, and eliminate O2 and exup valve from ECU. This also should fix or at least improve throttle issue. Downside it's generic(ish) map, and every time bike brought to dealer it needs a red warning not to update ECU. It's alsoore then half the cost of option A.

I feel like option B would get me a better running bike, but frankly I think I'll sell it this year, and more stock it is the better.

Thought?
 
HadesOmega

HadesOmega

Well-known member
What's wrong with the exhaust valve? That sounds like a major mechanical issue should probably get that fixed first. That what controls the airflow in the engine, besides the throttle body.

If a valve cracks or something it could cause more damage and obviously your bike won't run because it won't be able to compress air anymore.
 
stangmx13

stangmx13

not Stan
buy an exhaust servo off ebay, replace it yourself, and ride it. if u are going to sell it, theres not much sense in putting $$ into it.
 
UDRider

UDRider

FLCL?
HadesOmega said:
What's wrong with the exhaust valve? That sounds like a major mechanical issue should probably get that fixed first. That what controls the airflow in the engine, besides the throttle body.

If a valve cracks or something it could cause more damage and obviously your bike won't run because it won't be able to compress air anymore.
Click to expand...

It controls it at lower rpm and from my understanding there for noise/pollution not for operation.


stangmx13 said:
buy an exhaust servo off ebay, replace it yourself, and ride it. if u are going to sell it, theres not much sense in putting $$ into it.
Click to expand...

I am not that mechanically inclined. I can buy it from eBay and let independent shop install it I guess. Which would be cheaper, but I would still need to bring it to dealer bto figure out what's up with OWN sensors.
 
HadesOmega

HadesOmega

Well-known member
Oh haha I thought he meant the exhaust valve as in the valve that opens and closes that lets gases out of the combustion chamber
 
UDRider

UDRider

FLCL?
It's this thing:
servo.jpg
 
clutchslip

clutchslip

Not as fast as I look.
HadesOmega said:
Oh haha I thought he meant the exhaust valve as in the valve that opens and closes that lets gases out of the combustion chamber
Click to expand...
That's what I would think, too.

What bike is this on? Yes, they reduce noice. However, they also improve engine efficiency. The ECU will match this valve with the intake valve. It will open more with increased throttle AND RPM. This actually works. Disconnecting it will actually hurt performance, but many "performance-improvement" consumers are not that informed on how things really work.

If it runs off the Oxygen sensor, the ECU should run fine if reset to stock. Before you pay for replacement, hook everything up, reset the ECU and see what happens. Some ECUs take a period of running time/mileage to sync all parts of the system.

EDIT: [P.S. The O2 sensor could be bad and this would probably cost you less to fix. They can be tested.]
 
Last edited:
UDRider

UDRider

FLCL?
The Italian engineering Wonder. Lol

The way I understand it. It runs off o2 in closed loop up to some percentage of throttle opening/rpm. Then it switches to open loop and runs from preprogrammed mapping. Rexxer would put it always into open loop with some mapping for lower range. Since no Dyno is involved it would be for the model, but not specific for a bike. Which is probably good enough since from factory that's what map they load for open loop.

Right now it throws error codes/engine light since servo is kaput. Probably will run good enough, but something that I would want to fix one way or the other before selling. No one wants to buy a bike with engine light. Lol.
 
HadesOmega

HadesOmega

Well-known member
Is there some kit to delete the exhaust valve or just trick the ecu into thinking its still there?
 
UDRider

UDRider

FLCL?
HadesOmega said:
Is there some kit to delete the exhaust valve or just trick the ecu into thinking its still there?
Click to expand...

There is a dongle. It didn't work. There is quite a bit to this story, but not particularly relevant. Although I guess relevant part is if I were to go replacement route it would be through dealer, and not myself or independent shop.
 
Last edited:
stangmx13

stangmx13

not Stan
if a dongle didnt work, perhaps theres something wrong w/ the ECU. the "disconnected" O2 sensors when they are def connected might support this idea too.
 
UDRider

UDRider

FLCL?
stangmx13 said:
if a dongle didnt work, perhaps theres something wrong w/ the ECU. the "disconnected" O2 sensors when they are def connected might support this idea too.
Click to expand...

Maybe... Hope not. Dealer didn't think so. They said engine light is because of exhaust valve. There was an old error code for o2, but it wasn't responsible for engine light. Basically the story with o2 sensors is tech looked for them where manual said they were, but didn't see them. When I looked there were clearly things going in to exhaust where manual says horizontal and very lambda sensors were. When I called they said they will check when I bring my bike back in.
 
Last edited:
byke

byke

Well-known member
Exhaust valve confused me too! That's just a little backpressure doohickey for increasing low end. Tons of bikes out there without them. I'd disconnect it and find a way to lock it open, or rev it until it opens and unplug it, or maybe it has to be in gear on the stand or something, but basically find a way to get it to open itself and then unplug it.
 
byke

byke

Well-known member
I just mean to address the slam you forward part so it runs well while you sort out what you want to do with it. It must be moving to be doing that.
 
Blankpage

Blankpage

alien
It has to be fixed so you are going to spend at least the cost of option B. Therefore you can eliminate that cost from the equation.
The struggle you have is with the difference in cost between option A vs B. What is that difference in cost? If its only a couple hundred bucks then that is the cost of fixing your bike. If you're considering selling, it pretty much has to be in stock condition else the money you save is lost on the backend. A) is the answer to this conundrum.

;
 
Last edited:
L

lunchbox101

Well-known member
On my R6 I just disconnected the cables. The computer doesn't through an error code because it thinks its still connected. Default is open.
 
You must log in or register to reply here.
Top