♠️ M77
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Carefully and very very very patiently (so you don’t stress the intake pipes), you can get away with unscrewing the carb floats while still on the bike, but you need to drain its fuel first on the float drain screws.
Take a look at the pilots.
Try also 87.5 x2 mains which should be cheap on ebay ?
Mixtures = Don’t touch them ever if the bike is idling fine and changing gears smoothly (like no big “chug chug chugs forward and shoots off like a train” = carb issues or clogged carb again”)
If you have a mini air compressor machine with a small tip hose, you could blow the carbs clean under the floats to force stubbon internal dirt that’s inside the silver body of the carb.
Also on your chain kit, check the reviews as they mention what other riders setups were like and the kinds of speeds they got, to see if yours is on par.
5th gear is rarely used unless on a long A-road that’s 70 plus and your next junction is miles away , its more a stretch gear, most GV riders i know run around the city and never go beyond 40 miles out of their home address , so gear 1 to gear 3 was important to them.
Gear 4 and gear 5 , definitely keeps her calmer than screaming so much if on a long road trip on those long B roads or A roads.
Does it accelerate OK at 1st to 3rd gear ? and what RPM is 30mph ?
Grab a fresh set of CR8E , fit them in and ride for a short distance, come back, let it cool down, take the plugs out , take a few pictures and upload them here, so we can see what’s going on?
Either we have a fueling problem or the HT Caps (not coils) are waning or the carbs themselves need attention.As it’s idling, spray carb cleaner on the rubber intake pipes and find out if the revs change ? (It could be a good idea to change the O-RINGS under the intake pipes as if they are caked up dry , old etc, they will cause all kinds of weird issues when the vacuum system is not sealed tight.
Hmmm “as long as you hold the throttle a little bit, it wont stall” , right here, i would quickly double check your butterflies in the throttle bodies did not get modified ? and try this , disconnect the ISCV and manually connect 2 fresh hoses from intake pipes to the airbox , see if idle improves ?
Then we can confirm if it was the throttle body , but also if you managed to remove the throttlebodies, replace the O-rings under them to stop any small air leaks or spray carb cleaner there to see if revs rise or change?
Stator, Coil, Caps = Check this link below and look for my reply that tells you how to test them with a multi meter (Ignore that it says GT125, the testing method is the same for its 650 sister)
Rectifier – How to Test Stator , Battery , Regulator – GT125R Carby
What part numbers are printed on the coil or any picture you can post of the current coil ?
SV & Hyosung in earlier days used the same coil made by Mitsubishi Japan (the long oblong ones) so no difference , however the later smaller coils are made by Hankuk Korea , and Delphi Coils are Delphi only.
So if you have a Delphi coil that looks like a shotgun , then you can only use Delphi coils as not to trip up the ECU, Delphi ECU also expects the coils to have certain resistance secondary and primary , hence the forced change over to stop older coils fitting to delphi units. Their best upgrade for the coils is good HT leads & Caps (NGK)
The Delphi 650 (GV or GT) would get mostly the same codes but i’ve yet to find something “GV Delphi” specific yet considering both GT and GV don’t share the same ECU’s or dashboards, the flashing sequence of the red Fi light you said seems to match what i found in the books if its true. You would have to read the flashing sequences again , if it happens again but unplug the battery for a day (just to see if the same flashing errors occur) – The LCD panel is funny sometimes, it can say FI, 0, Fi, 0, while riding not telling me much, but if i park up and flick the kill switch 3 times rapid before starting, the red light will flash telling me the true issues. The red Fi light is more handy than the LCD panel.
Hope it works out well and you have spares for the future. The 650 is always fun to ride when everything works!
Would it be possible that your coils (on their own) or the HT Caps (problematic things) could be dropping out , wanning so that they fail & the bike cuts off ?
If the ISCV is truly working, have you tried a 2nd ISCV that is new so you can fully rule it out?
Can it ride in general (besides the idling issue?)
I am suspicious of either the stator pickup coil (wanning/haywire) or engine HT Leads+Coils or the ISCV unit.
I am not sure about injectors yet not unless your plugs are sparking dry / lean ? or fouled up bad ?
Grab yourself another set of new HT caps and coils to be sure (Stator , not sure yet but keep that in mind, usually if the stator-pickup coil goes at any point, so does everything on the bike and bike shuts off as it depends on it, the ECU checks that 1st)
I cant remember what the code is on Daewoo as its been a while , but on my Delphi if the ECU thinks my stator is suspicious , it sends a FI light with flashing sequence to translate to “pickup coil / no signal or pickup coil / noisy” etc and bike didn’t start till i replaced it but if it did start, i would see crazy jumps on the RPM meter then it dies.
It’s in the forum service manuals uploaded here:
[DOWNLOAD] Service Manuals & Owners Books – Hyosung GV650 & GT650 (Carb & EFi)
Regards
The closest i can get is 10-3-5-1 (Failing ignition coils)
Nothing i can see here for 10-3-5 (0r 10-3-5-0)
It has a spring, and washers and a sieve in there, it is purely for the gearbox cam shaft, because there is small parts there, so easier to service it after a rebuild, this is something of a concern for engine builders or garages rebuilding a damaged engine. It’s just an overengineered engine to be fair.
So general riders are told to just focus on #2 for oil changes.
1 & 3 – For gearbox area, so you got lucky!! _ Ignore them next time. Drain Oil using #2 in the picture
so the fact I drained from #1 is ok?
If the gearbox is OK and running, then don’t touch it again. You got very lucky! – Most owners who drain that #1 hole end up with all kinds of issues and have to rebuild the bike again.
You’re lucky!
Stay on #2 going forward , like this tutorial
[How to Tutorial] How to Change Oil & Oil Filter on Hyosung GV125 GV250 GT GT250R GT125R
It must have been the moan jet was blocked cause took her out for a spin after cleaning everything and re clamping everything and she seems to running perfect now no sticking at higher revs, also added a fuel filter and tested for leaks with carb cleaner and was all good so I’m happy camper just now!
Happy ending!
Hold tight a few more days, your special part is due to leave later in the week and i believe EVRi will come or RM , but i will definitely edit the order to reflect your new email address, email us by Thursday if you hear nothing!
Take it easy out there!
Replace the coil entirely and get new plug caps , then re-test , you want to rule out that completely.
Also open the stator casing and check the stator pickup sensor has not gone haywire ? CDi sends sparks to engine coils based on this item first.
Then double check the harness.
We hope you don’t have to replace the CDI as the last resort.
That’s new , if you ever do valve clearances next time, remove the cam shafts and tighten the long 4x engine cylinder bolts which holds the cylinder head & piston jug together , but this may help squash the gaskets a tiny bit (a tiny bit) , but worth checking next time.
That is my suspicion , it doesnt seem to come from the top of the valve covers but near the piston area, so could be piston jug gasket rather than engine crank-half gasket (bond), Hyosung uses factory “bond” to join the crankcase halves together, otherwise some people have been rebuilding engines with some gasket card and cut it to fit or they use engine bonds used by cars to bind the cases together , the service manual for your bike (at manualslib) should mention the type of bond used.
1 & 3 – For gearbox area, so you got lucky!! _ Ignore them next time.
Drain Oil using #2 in the picture
before refitting, did you consider replacing the intake manifold rubber O-RINGS , as these are known to cause hidden leaks causing all kinds of boggy behavior . If fitted already, spray carb cleaner around the intake pipes to see if revs change ?
Does it start without choke when its ice cold ? its a small tell tale sign if things are good under the hood, and normally it should not need it heading in to summer now.
To rule electrics out, check this link below and report back with your figures?
Rectifier – How to Test Stator , Battery , Regulator – GT125R Carby
wow , that screw is well and truly gone, i always wondered why the need for brass instead of stainless versions, they do that for the diaphram slides already, but i also would have loved to see stainless acorn nuts under the floats. Saving weight maybe?? I doubt it, the bike won’t notice a few grams being shaved off, its wheels are already a combined 40kgs!
Have a look at this tutorial below , you will need the chain attached as it makes things easier.
[How to Tutorial] Upgrade 520 chain & sprocket kit on GV125-S EFi (GV125 S 2019+ Models)
