â ď¸ M77
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Hi Marcel, hope all is well. When attempting to start the bike, no fuel leaves the tank. I also used âmannol 10w40â intsead of the recommended oil. Im going to put a new oil, fill up the tank and attempt to start again.
Low vacuum (intake oring leaks) as per my earlier comments above ^Â Â (or just see this link directly below)
Or tap issues.
And yes as long as the oil says JASO MA2 for motorcycles (certification) otherwise it may be car oil & you will have a lot of issues later. If it’s bike oil, i would replace it after 500 miles and use motul.  It sounds crazy but most people who say “any oil is fine” are the ones you wouldn’t want to hear their advise on serious matters anyway lol
If not , i would find a GOOD working OEM cap for now and use MAGNECOR HT wires alongside your new coils (replace both)
You got it! – If the coil is intermitent (haywire or chaotic) it will behave as your video did.  I would replace the coils and try to use NGK leads and NGK caps (The OEM Caps are too problematic to reliably conclude the matter as resolved)
The starter motor’s body was a hyosung creation to make it fit on the GD engine as it is one of a kind, but i can’t “confirm” if it is possible to use the “internal parts” off the GT250R , or 650 or the MS3 scooter.  The MS3 is very rare now but shares maybe one or two parts with the GD250 , such as exhaust sensor but for everything else, I personally did not do any detailed comparisons between the MS3 & GD250 as no one was interested , so I did not bother but my memory is faint.  It’s just an idea
If not, look for a shop locally that can rebuild starter motors for you on a lower cost until you can get a new one.
Hmm that’s strange.
If its H4 fitting, then yes it must be 55w type (The headlight plastic shell inside will tell you bulb size & watts)
Then while its apart ==> Reach the headlight 3-Pin Plug ==> Get a meter “red probe inside the YELLOW pin”  and “black probe on the grey or black wire”  (ignore the white wire) ==> You will know if 12V is actually going there, because Yellow wire is high beam
Report back and let us know.
35w bulbs use totally different fittings, so it wouldn’t go inside the headlight and they are for the 5 inch headlight from the early 200os era GV125s
Nowadays hyosung uses 7.6 inch headlight shells with H4 fittings since 2005 for the carb models
I had that before , it turned out that i had to sort out a few parts:
- Coils, Plugs, Caps in tandem
- The ECU wires had some oxidization, so had to clean up carefully and wait 24hrs to dry up
- Injectors just got replace (i couldn’t verify if they were faulty or not, but i just got new ones just to save future breakdowns, so new injectors advised!)
My last worry was the ECU itself but it would sometimes moan and say “Oxygen Sensor”  (lambda sensors on pipe) , it would run sweet once i got brand new ones, despite trying a few used sets from other donors.  The Daewoo ECU was frustrating to work with, Delphi ECU is a little better but it takes less nonsense! So much as a clutch switch fault ,it refuses to even crank.
though, keep an eye on the “idle speed control unit” , i can’t remember where but the manual mentions it.
Have a look at spark plugs (if they are brand new) , if they are wet = you have also possible stator problem if the coils aren’t sparking properly (they need the stator & ECU to time the sparks)
Glad to hear its alive!!! đ
The starting solenoid may be shot up. Replacement time.
Though, not uncommon but it happens, investigate the starter motor itself.  (Remove from engine, place on floor , get jump leads, put the bike battery on the floor)
I say this , as you may get sparks flying and wear gloves , do it away from the bike itself.  You will know if the starter motor is healthy and spinning strong.If you press start on the bike itself , and the engine makes a “big thud” sound at the crank ==> check your sprag clutch (behind the flywheel itself , but i hope not, as its means more work removing the flywheel!)
Good luck and try to take a break so you can enjoy your holidays and return to her with a renewed mind đ
Hmmm, fully charge the battery (with a bike charger instead of a car version due to excessive current damage)
Get fresh CR8E plugs , connect them to the HT caps , place them on the “unpainted” part of the engine such as a valve cover bolt, see how good the sparks are ?  Incase its not sparking strong enough to start ?
Also these stop sparks = Clutch Handlebar Switch (not recommended to bypass), Stand Switch (if bypassed check contacts again) , Neutral Switch stays “Green” on the dashboard
Also , this sounds stupid, do you hear the fuel pump priming when the key turns on?
Using the “Share Link or Get Public Link” option from either: OneDrive, GoogleDrive, Youtube (upload as UNLISTED!) , DailyMotion or other source to upload some video.
Paste it on the forum here, so we can watch what’s going on ? – Ideally stand on the left side of the bike (where the pump is, so the mic can pick up its priming noise)
But , do #1 & #2 before getting to the end of my comment.
Ps. test your stator & tell us the readings (service manual on this forum) , or if its suspicious, the bike won’t start without a good stator, it is the 1st thing it checks.
ECU primes fuel pump (unless its faulty or some other sensor in the bike is faulty , that means spending a lot of time with service manual to test every electric part you can find with a pocket meter) => Start Button is pressed => Solenoid Clicks to spin the starter motor => Stator Gets flywheel speed & pulses back to ECU => ECU, now does it’s magic to try start the bike assuming all sensors connected to it are saying “We’re good to go” or “not responding / poor response = Error Code / ECU shuts off ignition…Â Â This is just a simplistic way i can describe the process but the service manual ofcourse has way more detail in how their EFi system works
Push the whole cable outwards   , as that switch is slot fitted .  So push the cable instead of pulling it.
Switch is one-piece unit , it is the classic style before newer bikes had the switch changed entirely (as did their master cylinders too)
Newer Generation 125 engines & their electrics (RC / P models) , don’t really like bump starts and are VERY hard to start if it feels like parts are not in spec.
~if you try to start the bike with Jump Leads of a RUNNING CAR/VAN = It will never ever start again, bike is too fried.
If you want to use a car or van to start =Â Remove the battery out of the car / van
or i would recommend to just get a “Motorcycle Charger” (not a car one!) and charge the bike battery , weak batteries make it hard to start too.
I am digressing , but i hope that made sense.
Good, time to replace the starter solenoid relay and the starter motor too.  Then the engine should spin faster
In service manual it says if engine spins to slowly , there is not enough cranking to start it properly
Regulator = On this site, look at the shop product pictures, you will see how big it is but owners managed to fit it there. (Bigger is better)
It is the 1st thing i would replace yes,  other electrics should be fine. They can be tested later.As for wires, it’s hard to see properly , maybe I will have better answers as i study more pictures of your harness and its plugs , where they are connecting to etc and proper look of wire colours so i don’t make wrong assumptions.
The fuel tank level sensor must not be connected until you see the plug that has 1x Yellow AND 1x black on its white connector.
If there is suspicion on the fuel pump and the owner did anyhing sketchy to the harness to block the pump etc…. (ie. direct feed from tap straight to carb)
Then i would advise later down the line it is better to have a vacuum pump fitted to the bike.  We will get there slowly as I can see a lot to do there.  Send us a message on ebay if the center stand is needed and I may post everything at once
If the pump is not working, i would not get a new one,  nothing good about relying on electric pumps for carb bikes as there will be clones made in China.  All my own carb machines have mikuni vacuum pumps , they never bothered me for years on end.
Coming from ebay , we have discussed there what we can do about the Air System and I advised which parts to get, so i will keep an eye on your ebay before i post anything
Welcome to the dark side! And good to have you over here, now i can speak unfiltered because ebay really does hate it when i try to divert people out of the site (they want to collect sales & tax the sellers there lol)
Anyway, it looks like from the tank it does appear it has a fresh looking TAP that says “ON/OFF” this is good, as we don’t want fuel to keep flooding the cylinders after the bike is OFF.
Let’s see what happens with her using that electric pump
I advise to replace ALL the pipes (Hyosung service manual says if the lines are 4yrs old from the factory, they MUST be replaced as it starts to break down internally and cleaning them delicate japanese carbs is not fun at times!) – Your grey lines are OEM , so well over 22 yrs old. Plus it might burst when the pump starts priming the fuel.
And while at it, replace the fuel filter too. See here:
Uprated & Braided Fuel Line + Filter Kit :: Hyosung GV125 & GV250 {Carby Models}
Keep in mind and make sure the fuel pump is connected to the correct plug.
There is a WHITE plug that has 1x Black line and 1x YELLOW line with a black tracer on it , usually near the upper part of your seat, this is for the fuel tank SENSOR
The pump (in my memory , if i can….) should be dark , like 1x black, 1x brown/red … but either way have a look.
2PIN PLUG that is “Blue x1 and Green x1” would be for the Neutral Sensor that’s going near the sprocket cover.
Another BIG 2Pin plug that is “Blue x1 and Green x1” is for the Stator —> It is in tandem with another giant plug that is “3x Yellow Wire” is for stator unit too.
That silver regulator on the bike was recalled by Hyosung (gets too faulty and blows a lot) , and it was superceeded by a Larger Black Regulator (but is still trash!) ,  usually regulators are Hyosung’s #1 problem to this day as they don’t make them but outsources it to woochang , Sun Electric, Hankuk in Korea.
See this one:
Upgrade Regulator Rectifier [Reg Rec] :: GV GT 125 250 R GTR Hyosung
You will get her running , keep us updated!
Just avoid the EFi black ones! , as they got updated & the respective bikes had updated forks to fit them.
TCTC Silver = Identical  (Every Hyosung before EFi era)
So yes, you can get rear GT250 calipers , remove the bracket , and put them on your front mounts no problem.
Just bleed nipples may face down or up! (TCTC is funny like that!)
GV250 Front Caliper = Same as GT250R front , just swap the mounts as GV uses different forks that’s all. The actual caliper is the same.
KR Motors doesn’t sell calipers on their own, they “have” to come with mounts , probably why he said “i only have rears” .  As Hyosung Korea pre-fits the mounts at the factory as they make them after TCTC sends the calipers to them.
We can’t buy new mounts separately that’s why , they come with the calipers as a whole set.
No problem, least you have a spare rear mount!
In my comments above ^ = Read it and let me know if the sprag clutch is working by testing with your hand and tell me what the BIG sprocket behind the flywheel is doing when you spin both ways
And which direction is it spinning (towards front or towards rear)
And which direction does it refuse to spin  (towards front or towards rear)
Let’s just focus here first before i can address everything else.
The engine isn’t spinning properly that’s why.
Which Hyosung is this ? Becareful some sites are very sketchy with no real association with KR Motors Korea (Real Hyosung) but they buy their own stuff and store in a shipping container yard!
anyway,  if its SILVER and says “TCTC” on it , it is the same caliper used on front & rear for the GT250R before 2012
After 2012 = All GT250/650R used an EFi rear caliper which will NOT fit the front!
If you get a rear silver caliper that looks like yours,  remove the mount , and use the front mount.  As the rear mount is for the rear only.
The caliper is used on the 650cc, that should tell you that it’s more than sufficient for a 250cc motor and you have 2 discs also which is a luxury as most 250cc bikes only have a single sided caliper and disc x1.
So improving it would require these:
- Braided Goodridge UK/Hel lines, you want a proper motorsport brake line.
- Stainless Pistons , because all hyosung calipers suffer from piston corrosion and seizures.
- Stainless Pins (that your brake pads slide one)
- SOme good grease behind each pad and on the PINS
There, you almost do not have to worry about that caliper for a very long time , anbd also all you are doing is cleaning the caliper during brake pad changes.
GV250 uses the same caliper , just remove the bracket and use your own bracket.
GT650 , they got upgraded to the BIG 4 piston calipers (kawasaki look alike type of calipers) , but the forks also got updated. They will not fit 250cc without the updated 650cc forks.
Other brands = Not known, I doubt it!
If fitting other brands / makes == Fabricate a metal plate mount to affix the caliper to your forks and possibly master cylinder upgrade to 5/8Â (from St7, GV650, GT650 that fit 22mm bars as some cruisers have 1 inch bars!)
If your master cylinder says 5/8 = keep it. It’s as good as it gets and it’s very good.
You could still get 650cc calipers but must be identical yours (silver TCTC Korea brand), that’s pre-EFi  (around 2005-2008)
Be a good idea to go stainless on your rear caliper on its pistons & pins as here in UK, we get rear brakes failing more than the front!
Just make sure you looik at your flywheel starting system cause if a part is damaged , it could flow loose inside motor and damage something else like a loose tooth! This will save you damaging another starter motor.
If we sort the crank first , then starter motor , and now we can move on to engine and electrics and fuel system using my comments from the 1st reply i gave you above ^
So follow it over & over again. If you finish my list correctly, you will learn something new to fix or make good progress.
