♠️ M77
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By looking at this drain bolt, is there anything else I should be aware of?I see chunks of the flywheel sprocket!
And generally clutch metal shavings, i’d open the clutch cover and make sure all looks well, we do have a clutch tutorial on this site too.Topic closed , as it’s a duplicate and check your other one! ❤
Any pictures please?
Close up ones and also distance yourself away from the bike a little so i can see with a bird eye view but i believe with the 2 tutorials on this site, check your self they are routed well.
Search “Air Vacuum” and “Fuel Line” tutorials.Extra hoses will be a tank overflow that’s directly under the tank away from the tap , also EGR system (bypass it & get the extra blanks we sell at the shop if it needs more! – Some engine have twin EGR system (aka Secondary Air System Korea calls them officially) )
Just make sure the airbox is “blanked” from extra hoses coming out of it to the EGR
Is there anything you can suggest I try with carbs in-situ Marcel?
Check Pilot Jet , it gets clogged very easily too.
Then while carbs and airbox are still on the bike, you can spray EASY START inside the airbox
Disconnect Rear Coil.
See if the engine actually sparks the front cylinder in to life and activate full choke , it should try to get it going. I expect if fuel comes out of the front carb, the plugs must spark it.
Or rear plug will be wet (as it was disconnected from HT coil)
But front will be DRY if its sparking and trying to fire
If its flooding, it will be very wet.
Looking at front and rear plugs will give us much better idea what to do next.
And also as per Alan above suggestion ^
The “starting Jet” really actually deals with starting mainly or fast choke system . It’s the Pilots to keep the bike idling.
You can do this right away to help the bike long term
- Motul 7100 oil (strictly this , nothing else) – Get “10w50” grade instead of 10w40 (10w50 is allowed by hyosung)
Also it takes longer to break down , hence good quality oil i recommend it
Fresh oil filter (always) - Upgrade ignition coils (OEM ones on 125s tend to break down)(Common)
- Upgrade to NGK Caps (Better heat resistors) (OEM ones are made by GOLDEN company in China. Cracks a lot inside.)
- Check to make sure Regulator is 14v from idle. = If no, Korea says replace it right away.
- Check to make sure Regulator is 14v at 5,000 revs = If no, replace it.
Fuel System
Tell us below, first ….- have you replaced the fuel tap under the tank (too common) = No fuel or too slow –> Your carb drains its bowls and bike cuts off.
- Fuel pump – New one is a good idea, no rebuilt kits for it exist yet. = Slow dying pump means its prone to cut outs.
- Upgrade to fuel lines sold at this shop and it’s monstrosity filter
Hint = If the filter is HALF full when you finish riding , tap is doing OK
Hint 2 = If filter is Half-Full at 6pm —–> and at 10pm its emtpy === DO NOT RIDE the bike! (Your floats, pump, etc need check as they allowed fuel in to cylinders
Engine hydrolocks
And soon damaged piston rings with excess heat.
Just too many problems later. - USE E5 ONLY = Sorry for all caps but E10 really is a killer. If you use E5, then well done 😉
Carb System
This monstrosity is happiest when its had an ultrasonic bath and a wizard that’s tuned it properly to the tee. If a mechanic tries to tune a carb by “guessing” , do not pay him & don’t use him again.Sometimes tuning also involves checking float height is 7mm upside down
Carb Rebuild Kits include a float valve that actually has a “spring” on it, which can be dead on OEM floats after many years, hence if there is float issues = soon cut out and stranded.
If in doubt, just get new floats at the shop too & don’t adjust them.
Engine Heat = 100000000% recommended to get a 250cc oil cooler. It will love you for it.
We have more than 10x oil coolers for sale, just send us an email. Some are on ebay under the @Evocrest name with protective grills sold separate.Summer is coming.
Cool down that hot girl 😉
Give it to me straight doc, is it fixable?
Yes sir. It’s not dead yet.
Just remember to put where you find that tip and spring under the bike and carefully rise the bike (jack it up) and check gearbox works
Spin the wheel in neutral then select 1st gear while holding clutch, then try to spin wheel?
Try neutral again , and 2-5th gear to make sure gearbox is OK. As that element with a spring is for gearbox.As for the flywheel. You need to pull the flywheel off (Can get a puller tool for you if need be & ship it) , and also will send “used but complete sprag” clutch system as
I will have the kit (the sprocket & the crucial sprag-one-way bearing unit), i know its somewhere as we just had a donor bike to salvage parts from , so being weekend of rest, i will wait till next week to get it together!If interested , send us an email with exact parts list.
If i am honest , EFi has wayyyyyyy more electronics and more parts to change and the front cylinder head needs a special hole bored in to fit a korea ET sensor in to it.
You have a carby system that’s easier to get it going on road!
If you still have the twin carbs = rebuild it with a repair kit and fresh jets , and ultrasonic clean it, it really works wonders as there would be nothing blocking air and fuel mix in the carb body , even new slides are sold on this shop, i have it all.
Fuel Pump is not a bad idea to replace!
Fuel Tap is not a bad idea to replace either 🙂
out with the old & in with the repair kits / new parts , so to speak.
There is a fan that’s on the oil cooler. I would get rid of it. The oil cooler does the job very well and your climate is not the sahara desert so it will never burn itself , just make sure to use quality ESTER OIL as they really love premium oils. Even the gearbox will feel smoother.
I gotta say, he must have had so much trouble finding the Twin-Carb (OEM & best performing) , the owner had to resort to strange fabrications to make a single carb system.
The “Rubber Intake Pipes” that are on the engine heads are OEM and correct, look after them very well.
Looks like you need
– Twin Carbs (Hyosung GV250/GT250 Carb Type, not fuel injection models)
– GV250 airbox (carb type!) as injection model airbox does not fit.
– GV250 “Large” rubber airbox connecting tube
– GV250 “AIR FILTER” box that hangs on the side of the bike and is more enclosed (No pod filters as hyosungs had them)
– Possible throttle & choke cables if they are not OEM ones. (Carby type) as EFi injected doesn’t fit.Seriously though, big respect to whoever did the work to make it run on a single carb “BUT” he should have just found 2 single mikuni carbs (jap) and fabricate an airbox that accepts a filter and hides under the tank , like most bikes do.
It’s up you which direction you want to head to ?
– GO OEM (Recommended) but costs & time to wait for parts to arrive. (That’s if your local wreckers don’t have it, then i have to go get the stuff from donor bike as such)
or
– Spend lots of time away from the rain , as it doesn’t look like it will survive a rainy day and have to meticulously fine tune the carb to try run 2 engines in harmony.Morning David, only joined the forum recently and just read your post. congrats and well done for the perseverance. Beautiful classic tourer. enjoy!
Welcome 🙂
Sorry for the delayed response everyone. Nothing has moved forward with my bike as of yet because my little brother ran himself over with his truck
he is okay thankfully but I took a break with the bike to stick close by. Thank you Martin for your input on the website, I will steer clear of them. I am definitely worried about the seemingly scarce parts, so far I need a few parts and I’m hoping that list doesn’t grow lolFamily comes first, make sure he is good 🙂
I ordered parts from this website 4 weeks ago, chased last week and still nothing. Beginning to think it’s a scam.
hyoparts , spares and them clones should not be trusted at all now. Im sure i would have done everything i can to get you parts to your door as fast as i can.
When you get your cash back, just send us an email and ill see if i can get the parts or not and their timeframe to your door.
Oh dear! Marcel, I am despondent! I am back to running on rear cylinder only. I felt sure the bike would run, even with the front carb starting jet blocked with a broken off needle tip (!!), but it seems it won’t. I have a spark, but only running rear pot. Can you find me a front carb body or suggest anything else I can try. I will send you pics of carbs via email. I have all the new jets already, so can fit them to a body. Hope you can help.
No rush fella, I will try to “hunt” down a carb body but due to scarcity they aint cheap anymore even 2nd hand, so expect to spend 3 figures yikes.
I pray its still possible to save yours.
Update, purchased the flywheel puller and key. Pulled off flywheel, key was ok, not sheared. So stil just cranks, no start. Found a used, hopfully correct, hopfully working 2012 ecu in Spain. Hope to get and try in 2 weeks. Aarrgg
Fingers crossed because i have full EFi parts from a 2011 DAEWOO GT bike, and ECU is working too. (it could be sold as someone is asking for an ECU out of us) but we may have other parts for you.
You got this!
Hey , welcome 🙂
Please excuse my delay, I thought someone would have chimed in by now but it’s okay , we got you.
So , have you made any progress with your investigation ?
And have you checked out the tutorials for both “air” and “fuel” on this site to verify everything is in order?
Any doubts? – Just replace the tank tap (better new) , it’s on this shop.
Fuel Pump = We will get to this later, but the “tap” must defo be sending fuel in to the filter to confirm operation
Also the filter usually has an “arrow” showing correct flow direction because some owners put filters the wrong way and fuel doesn’t flow or come out. and pump will not run dry until it senses fuel. Then it sends it to the carb.
Welcome to the site , and glad you could join us!
Can you please show us a picture?
No vtwin Hyosung makes has ever ran well on a single carb , actually i would like to see what’s under the hood too, incase i spot parts that shouldn’t be there either.
Regards.
I have the starting clutch system in stock and i can remove it from the donor bike next week to ship over to you, just click “contact” at the bottom of the site and send us your address for shipping quotes and any used parts you want.
The teeth broke off because of either
- Engine is hydrolocking (fuel is leaking in to cylinders!)
- Starter Motor too tired (replace it)
- Starter Motor Relay (replace it , just for a peace of mind) , weak ones or bad ones will make the engine crank much slower.
I’ve had a hyosung that lasted 50,000 miles before i went to a different Hyosung , but it was more like “me being OCD” and overzelously maintaining the bike (What she wants, she gets right away lol, i don’t want till later to find problems or i just upgrade certain bits there and there) . I am digressing….
2. Fuel Leaks
Looks like you will need to rebuild the carbs (if its a carb) (as 2008/2009 is the “switch over year for carb to EFi) and make sure the floats are set at the correct height too and they don’t leak out. (A full carb rebuild kit is must)— Replace fuel tap (if it says “OFF” on the GV tank, disconnect the hose and see if fuel comes out) —- do this tank away from the bike! (fire hazard & fuel )
— Replace vacumm pump. It is a japanese Mikuni type but …. “weather & age of years” can make the rubbers brittle inside , so instead of trying to rebuild the pump, easier to replace it with a new one and it should be the “last defence” from shooting fuel towards the carbs when bike is fully turned off
IF it is EFi system , actually , it’s all carby , i seen the pictures above ^ – It’s a carb edition. So ignore EFi references above ^
The picture of you holding a part in your hand belongs to the gearbox , did you drain oil from the wrong plug then ?
Check this out …
[Tutorial] How to Change Oil & Filter on Hyosung GV + GT125/250 +R
I really hope you put it back where it normally is if you drained oil via the wrong plug (Korea could have made the 2 plugs under the bike further apart but engineers did what they had to do i guess!)
Usually a triangle plate with a plug under the bike means oil drain, as there would be a sieve/strainer hiding behind it – Not all brands like this anyway,
Well however. After 3 month i am officially alowed to ride this 22 years old veauty in swiss streets.
Time to have a nice drink and toast after your nice ride with it!
Never mind what they say , it still is pretty!
Also check & swap relays around, sometimes if one of the 3 or 4 relays behind the seat panels blows out, the bike then doesn’t activate anymore. Also check these
- Clutch Handle Bar Switch
- Side Stand Switch
- Connection to the ECU is very clean and there is not 1 single loose one (1 single loose wire can throw everything off)
Does it say F-1 or Fi (Fi is fuel injection system) (including what i said about the pump above ^ )
Also check (some models have it) and extra fuse box that says “30A” only, check them too with rest of what i said on the list above^
If you get time , try to trick the ECU to throw an error code (service manual in this forum on how to get error code … AB1223 , 456BC etc.. will say on the dash)
If push come shove , remove battery for 24hrs and reconnect it all again and try to start it , if not, check my comments above or trick ecu for error code. There is something that’s tripped the ECU not to start.
I just pray the ECU itself is in very good working order and the zillion wires that are going to it are in tact as it has multiple pins behind the ECU.
Just one-wire throws it off .
I’m struggling to get fuel from my tank into my carb, I’ve bought a new fuel pump and I’ve checked the hoses for any blockages. when I manually suck on the vacuum pipe fuel comes out of the fuel pipe but when I connect everything back up and try to start it nothing goes into to fuel pump and then into the carb, was wondering if there was anything I could try?
Fuel tap is faulty (just replace it as it will 100% leave you stranded) or there is lack of vacuum to open the taps when engine cranks.
Lack of vacuum follows on
- Rotted / Old ORings under the rubber intake manifolds
- Airbox is not sitting in the carb 100% (especially the front where tiny air still gets sucked in)
- Intake manifolds (spray carb cleaner when running to see if revs change , then intake pipes have a problem)
- Loose vacuum hoses or clogged hoses (i hope not)
- metal manifold clamps holding the carbs down are loose. (don’t overtighten as inlets are very difficult to get brand new)
Nice tutorial. But i have to correctyou on one point. On the 2001 gv125 aquila the stock pilot jet is 17.5 and not 15 like you sayed.
Domestically in UK we have stripped them and found them to be size 15 and it seems to match our findings on Korea’s parts database in KR America they use for dealers , but it is possible 17.5 is used in other countries anyway.
At the time Euro3 laws came in effect , the newer bikes even had EGR stuff fitted to them (to trick emissions laws) , but at the end, it made bikes a little leaner. If korea uses 17.5 , they downsize the CO mixture , if they use 15 pilots , they enrichen the mixture a little bit 😉
Same engine as GT125R bikes , no GT125R bike in world has had 17.5 pilots as they changed to MK2 carbs with jet pumps at the side…. meanwhile GV & GT Naked shared same carb around 2001-2005 with same settings. GTR bike came much later.
98-01 – GV
2003 – GT
2005 – GTR😉
I should add that some GV125s in UK started coming with 17.5 pilots again. Weird if you ask me!
Size 15 seems to be right size pilot , i mean 250cc is size 20 it’s perfect for it. 22.5+ etc will just waste fuel .
- Motul 7100 oil (strictly this , nothing else) – Get “10w50” grade instead of 10w40 (10w50 is allowed by hyosung)
