♠️ M77
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Strange,
When you click “Add Media” on your Phone , click “Upload” button as shown below:
Then find the source of the picture (In this case, navigate to your DCIM/CameraPictures Folder in your phone)
As for your GV, if there is no display cluster , it will run without it but ofcourse you need to see what is happening though. Do you have a local breaker where you are to find a wrecked Hyosung GV250 EFi to get its dashboard? And possibly a spare ECU.
Since the bike is EFi , it uses an ECU only , so no need for a CDi (for carb models only)
Based on your ECU, you have a 2009-2012 model which has a super super rare ECU (that ECU is not made anymore by Daewoo, hence Hyosung upgraded their harness and ECU to Delphi Electronics after 2013+ – I hope that ECU of yours is intact.
If the stator looks damaged, that could be a source , check the flywheel isn’t damaged in any way before it kills the next one as there is a very narrow gap between the stator and flywheel when it spins.
Hope you are able to upload a picture from your phone/pc to show us ?
If not , alternatively upload pictures to imgur.com and copy the “BBCODE” —> come back to the forum –> click “TEXT” (next to visual blue tab) in the reply box , then paste the BBCODE here. The forum will fetch the images remotely where you uploaded to imgur.com
I will do my best to recode this site again so its easier to make uploads here.
Yup, EFi will be fine on carby. Just plug the extra unneeded holes 🙂
Where it says “Add Media” on top of the reply box here , thats where you upload pictures 🙂
What ECU does it have ?
Do you get a flashing Fi light on the dash? How many sequences?
Eg. 10 blinks _ pause _ 5 blinks _ pause 4 blinks = that’s 10 , 4 , 5 and it repeats the same sequence , we can then use this sequence in the manual to locate a specific error code and why (manual is in the forum for download, it explains how to trick the dash to give you a blinking error sequence)
Keep an eye on the spark plug , see if it turns brown because “pure white” isn’t good long term, it suggests overheating soon due to low fuel at high revs / high loads or the sparking system stops firing every now and then when it gets hot (but then if it stopped firing, plugs would be very sooty wet with unburnt fuel)
Keep an eye on the injector and fuel pump!
There is a few youtube videos on guys with very old suzukis as they still had metal tanks, some use vinegar, some use white spirit combinations and there was a product used to clean car tanks (metal tanks of old 20th century cars) but keep forgetting the name of it, some also use metal marbles and shaking the tank all day , then using magnet sticks to scoop out floating rust after the fluids have drained out. There is many ways to do it , just make sure the tank is fully dried out but if liquids touch the paint, be ready to cry and likely go to the bodyshop to get it resprayed properly.
Compression Loss as per manual, so i will quote it from the horse’s mouth:
Low compression pressure can indicate any of the fol
lowing conditions :
●Excessively worn cylinder wall
●Worn-down piston or piston rings
●Piston rings stuck in grooves
●Poor seating of valves
●Ruptured or otherwise defective cylinder head gasketNow i’m just waiting for my right hand switch replacements, the start button pinged off on my second day lol
Blame the last owners for pressing too hard! Hope that gets fixed asap , we got a few weeks of summer left.
It sounds like a battery went out (inside the dash) – Some hyosungs have it (so look inside and check) but other Hyosungs even GVs store that in the micro-chips. I’ve been there myself.
I just tell the MOT guy to check the last mileage and i took the picture when it turned zero , then told him how many miles i did afterwards
You can also check the “Trip Meter” to see if it saved anything by pressing the select button, but if both say zero , then yes you encountered the rare moment where the dash just went to zero!
Unless you have a spare harness to connect the dash and battery away from the bike + front wheel on a conveyor belt + run it for days , the dash will start recording mileage because it thinks you’re driving. I’ve haven’t found other ways to cheat the mileage counter without breaking something.
Yes you need fairings off, then use jacks to rise the bike up safely. Then remove the shock from under the bike , adjust it while it is out of the bike
OR if you have very small strong hands, go where the rear brake reservoir is, use a C-Shock tool to rotate the shock a few more clicks until the springs feel stiffer.
I think its time to rebuild the front cylinder
At minimum, you want around 125 PSI
Hyosung says the limit is 110 psi hot and healthy range is 140 – 175 psi
Here is a cheap front barrel and piston, it should be OK
https://www.ebay.co.uk/itm/256864818680And here is a spare one
https://www.ebay.co.uk/itm/255751060887I have confidence that either of the above will finally get the bike running.
Ofcourse make sure to get new gaskets you see on this shop
Rear is already at the limit of 110 psi but… If you have to do the rear, then check these out
https://www.ebay.co.uk/itm/256513929819Hyosung Korea isn’t making new pistons for carb 125cc or rings.
I am slowly researching and soon will test custom piston rings off another bike that may fit our bikes. If you just want piston rings, then i think you should email me , but stock is rare now.
This is why you can’t idle, the compression is too low.
Did you test the compression again one more time please and use the “METAL Pole” like this:
Use the Straight one with the curvy rubber tip, and press down hard on the spark plug hole.
Tell us the compression (even cold, although “hot” would be prefered as per OEM ) with full throttle and both plugs out.
Do this with a fully charged battery
Yes,
EFi cylinders have extra holes for E-AIS (electric air intake valve thing for fake emissions) and ET sensors (Engine Temp Sensors.)But yes you can use any 250 cylinders and plug up the EFi holes. Tensioners depend on cylinder of course.
I would not whatsoever use chinese carbs , many tried and failed. If Hyosung had to use a carb giant like Mikuni Japan, then it’s £600 new that’s what Mikuni Japan would want hundreds , not Hyosung as they still have to pay Mikuni to make us a double carb specifically for the Hyosung 125
What is actually wrong with yours ? This site has every possible part to replace its internals, all we need is your skeleton shell.
Something i’ve learned about high temps is the spark plug cap , i can’t remember if you have an NGK one fitted but the stock ones just aint good. Another thing to look out for is the ignition coil, it does happen too but less often than the plug cap.
the plug should be mud brown / beach seaside brown all the way , if unsure , post a picture of it.
Always a jaw dropping moment going through these Passes , good to see the bike out & about 🙂
Yup , just as Simon said , if its the carb float bowls or top diaphragm covers , then it points to the ground (road)
Fuel Tank Overflow = To the road too!
Not just the pilot jets clogged, but remember the “Permanent Jet” that is next to it? That is for starting and nursing her to idle back to Pilots. Those 2 cannot be blocked and including the passages inside the carb itself.
If the Pilots are clear, but also use Compressed Air with a straw, spray every little hole you see inside the carb until you can hear swooshing inside (pathway now clear)
Remove the intake manifolds -> Replace the o-rings (These little bastards) make the bikes hard to idle if they even so much as let some vacuum escape under there
If the o-rings are new -> Try to fully clean the surface where they sit so it’s 100% smoothed out. use a PLASTIC toothbrush and scrub hard (no wire brush!)
Then use a little bit of Engine Oil to dress up the o rings wet and install them back.
When it runs , spray carb cleaner around that area to see if revs rise again, then you may have some kind of crack on the intake pipe itself.
AirBox = Front Carb on front Cylinder ==> Check the airbox has fully consumed the front carb, if you see silver lip (carb top rim?) sticking out, there is your future idle problem there.
Final checks, make sure when its hot, do a compression test. I believe it really needs compression checking now.
Let her warm up 10 mins.
Both Spark Plugs out
Full Throttle
Crank It for 5 seconds
Get readings for each cylinder and let us know.I went all over the place in my reply but i hope i made sense.
520 Chain Kit & Clutch Upgrade.
The 520 kit is one of the best life changing mods for the GV125-S , every customer i know did not go back to stock 428 skinny chains & tiny sprockets.
Clutch = It just compliments the 520 upgrade, your clutch will have a bit more punch 👍
Exhaust = Get a garage to cut yours and weld a 51mm cone ===> Get / Find a full size 51mm exhaust muffler that you like
but remember All GV125 including 2001 models all the way to 2025 models will run SLOWER if you do not keep DB-Killer inside. It is because GV pipes are too short compared to Hyosung GT bikes, the GV models I tested (both carby and EFi) always hated it when I installed very small exhaust cans
Yes the noise is good , but the performance was rubbish. I used OEM exhaust and drilled a bigger hole for nice sound and the other bike I used OEM Harley 2022 exhaust pipes as a custom job.
Chinese cans from China = I did not care to try , they look like they will rust in 2 winters and look poorly made. The EU where we live is very salty and wet , especially UK!
If you want a good example of an exhaust that does not make your bike slow ==> Look at LEOVINCE Exhausts for GV125 and GV250 , then ask your mechanic to see if he can do something like that.
Whatever exhaust you have , make sure it is long enough to reach the chain adjuster
Keep us posted.
Your old battery may not be holding its juice very well (weak cells inside despite whatever voltage it says) , a fresh YUASA is advised yes (make sure it’s a genuine one from Halfords or TanyaBattery on ebay , other sellers selll either fakes or very old stock!) Time stood is the battery’s enemy, so the fresher the better.
