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Removed both STV plates, all went ok. I didnt touch or adjust anything else, the only thing I did do was manually move the plates so they were flat so I could more easily get the screws out.

Started up the bike first time all seemed ok. Got on it for a test ride, got half a mile down the road and the red light came on with F1 showing a fault code I guess. Bike seemed ok though kept riding a bit until I pulled up and noticed the bike was idling much faster than usual about 3k rpm.

Got it home, turned it off, back on again and the fault code had cleared and it was idling ok.

Anyway, since then I have had several trips each time the FI light comming back after a random period of time, this morning I managed 15 miles before it came on, but gernally the bike was running really well.

Got home this evening and though if I put the STV plates back on, to see if it would stop the fault comming back. Did that, took the bike out and it ran like crap,. Fristly the FI light came on pretty quick, and the bike had much less power, particularly at higher RPM, at least 20% drop in power and th epower was bogging and surging.

Took the bike back home, removed the plates again. Ran it again, and its better, but still not running right, id say its down on power maybe 10% at higher rpms and the power bogs/drops a bit now and then.

Anyway ideas? I wish I had not messed with it now worried I have messed up my bike.

Bike is a 2003 SV 650 by the way. Thanks all.
 
Removed both STV plates, all went ok. I didnt touch or adjust anything else, the only thing I did do was manually move the plates so they were flat so I could more easily get the screws out.



Started up the bike first time all seemed ok. Got on it for a test ride, got half a mile down the road and the red light came on with F1 showing a fault code I guess. Bike seemed ok though kept riding a bit until I pulled up and noticed the bike was idling much faster than usual about 3k rpm.



Got it home, turned it off, back on again and the fault code had cleared and it was idling ok.



Anyway, since then I have had several trips each time the FI light comming back after a random period of time, this morning I managed 15 miles before it came on, but gernally the bike was running really well.



Got home this evening and though if I put the STV plates back on, to see if it would stop the fault comming back. Did that, took the bike out and it ran like crap,. Fristly the FI light came on pretty quick, and the bike had much less power, particularly at higher RPM, at least 20% drop in power and th epower was bogging and surging.



Took the bike back home, removed the plates again. Ran it again, and its better, but still not running right, id say its down on power maybe 10% at higher rpms and the power bogs/drops a bit now and then.



Anyway ideas? I wish I had not messed with it now worried I have messed up my bike.



Bike is a 2003 SV 650 by the way. Thanks all.


Vac line hooked up to the manifold pressure sensor?

-ms
 
How did you "manually move the STV's"?

You need to turn the nut ONLY on the actuator gear shaft. I hope you didn't force the STV's by pushing up or down on them.
 
How did you "manually move the STV's"?

You need to turn the nut ONLY on the actuator gear shaft. I hope you didn't force the STV's by pushing up or down on them.
Yup thats exactly what I did. :no: - well I moved them by pushing the connecting rod on the right side of the throttle boddy if you looking directly down on it.

I put them back in to the position they were, and the bike is running ok again. Power back to normal, no bogging or surging etc.

After about 3 miles or so the FI light came back on, same issue where the biks is idling about 2.5k RPM. Switched it off, back on again, fault cleared, went a few hundred yards down the road and back on again. Same after a 3rd time, all three times when the light came on it was under some pretty hard acceleration.

Got the bike home and quickly whipped the seat off to check the code and its C28 STVA.

Any ideas what I need to do from here?

I have a service manual, the bit 5-29 STP sensor adjustment, reckon that will work?
 
Ok just an update.

I took off the airbox and got my multimeter in there to test the readings.

Fully closed I am getting .52 ohms.

Fully open I am only getting 3.7 - 3.8 ohms.

Aside from being fully optimal (more worried about just making sure the bike is ok) are these readings ok, or too far out of spec?

Also I note, when both valves are fully closed, they actually rotate slightly past being completely flat, maybe 5 degrees over, is that normal?
 
The service manual should say what ohm values are in spec.

You could try removing the STV's all together too. I have. Left the shafts in though.
 
The service manual should say what ohm values are in spec.

You could try removing the STV's all together too. I have. Left the shafts in though.
Yeah the STV's are out, the valve plates that is, I dont want them back in either, thats why to a certian extent the readings are irrelevant I just want them within enough tolerance so they dont throw up the warning to the ECU as otherwise the bike is running fine now. Im gonna put the bike back together later today maybe, and give it a test ride, I am hoping I may have solved it though.

When I first used the thing you are supposed to use to move the STV's, they could not move through the correct roation, they were going past flat (probably a good 20 degrees) and when fully open they were only about 70 degrees maybe.

I basically manhandled the rod back once, in to what I believe it now the correct position, and then tried again with the little gear you need to turn by hand. The STC valves (or that shafts left in at least) now rotate correctly (or very nearly) and go from about 5 degree past being close when flat, to about 85 degrees when fully open.
And the resistance readings are .52 close and 3.7-3.8 open (thats is ohms not volts)

I am hoping now, that sensor will be a bit happier and hopefully not trigger the fault and I have not done any more permanenet damage to the throttle body, but it did seems turn ok when I used the little finger gear, so I am keeping both sets of fingers crossed.

It may be obviousl I don't know what I am doing, but the guide post I read (on another forum) about removing the STVs made it seem so easy, otherwise I would not have messed with it.

Wish me luck.
 
Right.

Put the bike back together, took it out for a spin, half a mile down the road, the FI light came on, needless to say I was pretty gutted being I thought what I did may have fixed it.

Took it home and as one last ditch effort before calling it a day and given Steve at teh bike garage a call, I losened the senor and shifted it around a bit, taking a reading to measure the resistance and it was higher when fully open 3.9 open .8 closed. I figures higher resistance, higher voltage, and its a voltage check it does.

I also checked before I put the airbox back on, I have set both valve spindles to a fully closed postion, and when I flicked on the ignition, they did adjust themselves to about 50% open.

Put it back together, back on the bike, started down the road dreading but expecting to see that light come on at any second.

Well....

I've just got off the bike, 40 minutes on the road, pushed it to 115 mph several times and on one section on the way back push it up to 125 mph.

No FI light.
 
I've only done it twice- once to see if they really did suck that much fun out of the bike, and again recently to check the tune if I sell the bike.

Tune validated, they're back out :yes:

.
 
Brock's performance found the STV's close to 64% when over 11k rpm's on the new Gixxer 1000.

You could watch them and see for yourself if they don't open all the way at WOT. Probably have to have a dyno though.

Not sure why they close.

With them out that won't be an issue.
 
The modern Superbikes might not respond as we'd expect on a dyno. If it has Traction Control (including wheelies) what is the ECU thinking when it's running flat out but the front wheel isn't spinning? Could it be thinking it's pulling a big wheelie and trying to cut the power? Not sure, but actually riding the bike....does it seem like it falls on its' face at 11K? From the reports I've seen...the answer is most assuredly NO!!! The bike rips.:) And if it can rip with the STV's closed a bit...oh well.
 
What Dale Walker thinks of them on the new DL's motor.

https://youtu.be/cMztucU2T6o


This is great work. But it only shows 100% throttle. I wonder what the behavior is at other throttle positions and how that would change output.

These bikes are so heavy in crank inertia, I would think this could be more of a limiting factor in getting the bike to accelerate.

Thank you for the link.
-ms
 
stv setting

G'day all I was tampering with my sled tonight doing the pair to crank vent change as was suggested, easy enough job only cost me 55cents and really impressed with the info supplied. Have not fired it up yet, still tank off etc to do fuel filter mod and tb sync, tps setting and of coarse set the stv to as close as possible to the parameters given.
bloody things where way out. closed I was getting .80 ohms and open 4.9
As I was dicking with them to be 90 deg at wide open and read only 4.38 I noticed at fully closed the stv butterfly plates end up going past the horizontal in relation to the tb bore

to obtain even close to the .58 ohms when closed I had to adjust the spring loaded actuator levers on each stv and I'm still not happy. The butterfly plates rotate past 90 degrees and there for from idle or low revs need to travel back past flat position before more air is allowed to catch up with the primary plates.
Is this normal op that others have noticed. the stv position sensor is all the way to one side of the slots for adjustment and needs to go more. just doesn't seem right
 
G'day all I was tampering with my sled tonight doing the pair to crank vent change as was suggested, easy enough job only cost me 55cents and really impressed with the info supplied. Have not fired it up yet, still tank off etc to do fuel filter mod and tb sync, tps setting and of coarse set the stv to as close as possible to the parameters given.

bloody things where way out. closed I was getting .80 ohms and open 4.9

As I was dicking with them to be 90 deg at wide open and read only 4.38 I noticed at fully closed the stv butterfly plates end up going past the horizontal in relation to the tb bore



to obtain even close to the .58 ohms when closed I had to adjust the spring loaded actuator levers on each stv and I'm still not happy. The butterfly plates rotate past 90 degrees and there for from idle or low revs need to travel back past flat position before more air is allowed to catch up with the primary plates.

Is this normal op that others have noticed. the stv position sensor is all the way to one side of the slots for adjustment and needs to go more. just doesn't seem right


Please check your units. Fully closed you should read 0.58 k ohms.

Full open is 4.38k ohms.

Voltage fully closed should be 0.58V

Full open voltage should be 4.38V

-ms
 
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