GV125s idle speed when hot / ISCV problem (Idle Speed Control)
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I finally had the time an weather to ridea a little longer and i noticed something (dont know is that an issue or a feature π). When the engine is hot (two bars) and i hit the clutch and release gas it doesnt go to 1,7-1,5k rpm but stays around 3k (or fluctuates 3k-2,5k rpm). It happens as im riding, or at full stop at crossroads etc. When i rev it up it sometimes goes back to 1,7k rpm. Also when left alone without gas i drops down. Is that supposed to be as is, or there is something wrong?
Spark plugs new, valve gaps adjusted, new oil and filter, new air filter.
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As per simon says,
i wanted to add by saying flactuating idles may also mean that it’s time to check for these too:
- Airbox Sensors (air sensors) are not clogged up?)
- Air leak around the intake parts of the bike ? causing surging revs and dipping revs etc.. (like a yo-yo)
- Lambda sensor at the exhaust, give it a good clean and retry
- If you are near shops for cars or bikes , please by this product below , put “ALL OF IT” inside the tank,Β Β (and use maybe half a tank or normal fuel to mix), now this liquid will travel all over your fuel system and try to clean anything that’s clogging upΒ (funny revs can also be a sign the bike is “trying” to hunt for fuel to make stable revs or it revs higher from ECU to stop it stalling)
- ISCV (idle speed control valve) – Common Hyosung thing, sometimes they work for years without issues , but check it , it is near the airbox. it is electronic with a big plug usually (but Hyosung may have shrunk it)
- Do not use Redex. Only this product is my recommendation.
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ISCV on EFI? On the schematics i only found tps (throtle position sensor) and AIPS (air intake pressure sensor)
Yes every EFI Hyosung since 2008 has had an ISCV to control the idling speed, otherwise , you might have an early batch of the GV12-S that doesn’t have it ?Β Sometimes it acts as a fast choke to warm up the bike in brutal winters
Also i know for a fact Hyosung used 2 variant’s of ECU’sΒ , early vs later model, the later models use a DELPHI ECU with twin plugs and a whole new harness (assume this means electronics also changed to delphi)
Ie.Β 2008 GV250 Had SENTEC ECU with sentec marked electronicsΒ vs a 2016 that had DELPHI and everything else was delphi branded
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is this it?Looks like it !
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Just did a test run, 30km and can confirm thi was the cause of my issue. Furthermore it doesnt stutter when decelerating anymore (it was very rough prior to repair, so much that i stopped breaking with the engine) It’s a different ride now, love it even more. Once again thanks Marcel for shareing Your knowledge π
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Just did a test run, 30km and can confirm thi was the cause of my issue. Furthermore it doesnt stutter when decelerating anymore (it was very rough prior to repair, so much that i stopped breaking with the engine) Itβs a different ride now, love it even more. Once again thanks Marcel for shareing Your knowledge π
You are welcome! β€
Enjoy her now π
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Hi all,
I know this is an older thread/post but I am having a very similar issue. Though mine is extremely intermittent.
for example I did my 2 mile trip to work and she was fine then left work and did a 3.2 mile ride to Hobbycraft and it was also fine. But leaving Hobbycraft to go the 5 miles home it decided to do it. I killswitced and turned off the ignition then restarted the bike and everything was normal again.This has been happening for a few weeks randomly like this for both long and short trips. I have replaced my spark plugs and HT leads hoping this would solve the issue as my old ones were gone.
I have checked the idle throttle position sensor as above and the only thing I have noticed is in the airbox between the two intakes to the engine there is a crack/split right in the middle, it doesnβt go all the way through but could this be the cause? If so any ideas on what would be the best fix?
If it helps this all started happening after I went to a jet wash to clean the bike. (Original HT leads on at this time so this is why I suspected those being the issue.
Any suggestions would be much appreciated :).
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Remove the airbox carefully and inspect the throttle body O-RING (There is an O Ring which connects the metal bodies to the plastic airbox incase of any leaks caused by a stone/dirt ingress somewhere ?
The crack you see there, can you shine a torch through it for any possible pin-hole gaps ?Β – find some kind of tiger glue seal to patch that area and see if that helped ?
I’ve not seen that before, did the bike fall and airbox got warped? or did something hit it ? that should not happen right in the middle where throttle bodies are exposed, also while the throttle bodies are out,Β use carb cleaner to clean it (not the plastic sensors or plastic airbox!)
Sensors on the throttle body = Only use contact cleaner to clean the connector sockets. Helps improve signals to the ECU for a smoother throttle response
Hope that helps!
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I have taken the airbox and checked the orings and there is no debris and they look fine to me.
I cant see anything coming though but I will try sealing it just incase.
I did drop the bike on its side not too long ago bloody gravel on the road caused me to slip and drop the bike. Low speed but still.
I will give these suggestions a go over the weekend and come back with an update :). Thanks for the advice :).
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Here are photos of the cracks- You must be logged in to reply to this topic.