♠️ M77
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Did you send me a message on ebay ? (@Evocrest is us) – I’ve only just logged in to see this
Thanks will strip it down and give it a good clean
Keep us posted, ultrasonic cleaning (not rattle cans) , really pays off and please only use e5 fuel where possible because e10 just isn’t great. And fancy 2022 cars don’t drive that much better on e10 either, where e5 gives them better mileage & e5 on bikes doesnt go off as quick as e10 does if bike has been stood before you bought. But as simon says , long standing isnt good for carbed bikes anyway.
if you have fuel lines older than 4yrs (oem) , as per service manual please replace them and get fresh fuel filter, the bike will thank you for that.
Carb Jetting is below (to help the main jets pick up better when riding, and slightly rich jets is better for a hot engine so it doesnt lean out full throttle, especially with 125 bikes commonly having aftermarket cans fitted (more air out or in = more fuel in) (electrics beefed up only help burn the fuel better , eg throttle response is a bit more snappier that’s all but pays off)
See the 2 links here.
[Tutorial] How to swap Carb Main Jets – Hyosung GV & GT 125/250
[Tutorial] How to adjust Carb Slide Needle (Tuning) – Hyosung GV & GT 125/250
Oh wow, do post us some pics or a jornual topic that we can follow on the racing section of this forum.
That’s great to know races still happen with hyosung 250s , these pocket rockets , the 650s usually a common choice for a track bike but don’t hear about 250s much these days.
And ofcourse ,post away any woes you may have so we help you restore it.
Welcome to the club 🏍🏁
The 650 one will fit because they use the same GREY yokes.
Funny thing is i am due to start getting my guy who does prints to make us some custom decals to put on the shop, so keep an eye!
Will even try to bring back the famous union jack flag also & some kind of carbon effect, but ideas are always welcome 😉
The entire engine uses 1.5L of oil, see tutorial below on oil change guide https://hyoriders.club/forums/topic/change-oil-filter-hyosung-twins/
The good oil for summer is below (& HIGHLY recommended) and the service manual itself says use “premium” grade oil (not the cheapo) to extend engine life.
- Motul 71oo = 10w40 or 10w50
- Motul 300v = 10w40 or 10w50
- Silkolene Pro 4 = 10w40 or 10w50
- Silkolene Comp 4 = 10w40 or 10w50
These are also ESTER grade oils. I personally never use anything else on mine except these 2 brands and when i fix customer bikes, its what i use also.
If you have no local breaker near you that does Hyosungs , then you can always send an email , but below is 100000000% recommended and the bike will thank you.
- 250cc EFI Black Oil Cooler (forget grey ones) and becareful on ebay some sellers are dishonest and 50/50 chance half the coolers sold there come from bikes that blew their cranks and metal debris may still be floating inside the cooler, restricting flow or will be picked up by the drain plug magnets.
- Uprate your bike to have better jets (see tutorial here https://hyoriders.club/forums/topic/tutorial-hyosung-gv-gt-125-250-how-to-swap-carburetor-main-jets/)
- Improve your slide piston to be slightly more enriched (see tutorial here https://hyoriders.club/forums/topic/tutorial-carb-slide-needle-tuning-hyosung/)
- Go to our shop above ^ or ==menu== if on mobile phone, and get yourself stainless steel bolts and “possibly” fresh carb gasket kit if its an old carb that hasnt been touched for years, to avoid leaks, fuel zone is a critical area we don’t want to mess with it.
- If you can’t source main jets, send us an email , we usually keep stacks of them as we include them as part of K&N kits for the shop anyways.
I moved your topic to the technical section and edited the title for you.
Hope this info helps!
Actually I took the starter in to a specialist and he opened it up and said the inside was fried. He is looking for parts to rebuild it.
Tricky things to rebuild them starter motors but hope he scores the parts. You, yourself should have a phone handy and talk to WhyGoStock, they are a real Hyosung USA dealer and will most likely have the part you need. They are much closer, and will be quicker than us trying to send parts to you, just consider us as last resort.
I think your mechanic has got this i hope, keep us updated!
I just removed a striped safety torque bolt from my 2009 gt125r exhaust front downpipe as my new blackwidow exhaust came today were can I get a replacement bolt for the damaged one I removed thanks.
I hope not, if anyone owns a 125cc will tell you dealing with Torx bolts is their worst enemy and they tend to replace the entire engine bolt set.
Look at this , you will do a whole lot better hereHeader Pipe Copper Exhaust Gasket & Full Stainless Stud Nut Kit :: Hyosung [Various Models]
Remember if its a “Hyosung” the consensus is to try to make every small screw stainless against the harsh weather elements & less fighting when its maintenance time.
If its just 1 bolt you need, do you have a local car shop? Just walk in with the damage torx bit and ask for this exactly below
“Hi, this bolt is for my exhaust but its damaged, can i have a stainless steel replacement ? The bolt must he a “HEX” head please. NO ALLEN KEY.”
Or “This above ^ happened, and i need a “stud that is 40mm long” and an “OPEN STAINLESS NUT” (This will be tricky for them to do!)
but you get the gist sir 🙂
Thank you so much for the detailed reply. I will try but it may take a while.
It’s okay , the art is not to rush. You will surprise yourself too. If in doubt record yourself or take pics so you always know where things connected back.
We’ll be here if you need help.
Hey welcome.
Do you think you have either instgram , youtube, or vimeo or any other public site that lets you upload a video and copy it.
Come back to the forum and just share the link to it.
This way we can see & hear what’s happening to the bike.We may go back & forth to get you the right answer , so i will start with the basics….
- What year is the bike?
- Do you use e5 or e10 fuel (or what does the pump say on your petrol station forecourts) ?
(Here in UK we discourage the use e10 even if the bike is rated for it, due to the fact bike simply runs better on e5 premium fuel & less maintenance of the fuel system to worry about later) - Do you or have you used any products such as “WYNNS GOLD PETROL SYSTEM” cleaner, which you fill up in the tank (all of the bottle) and mix with half tank of normal fuel. This will “try” to soft clean your injectors, pump, etc
- Do you get any Fi warning lights on the dash ? (or maybe we will see it from a video?)
- Has the bike been modified in anyway ?
- Lastly, if you have the physical service manual with you, can you go to a page that talks about getting error codes to display
Usually error codes displayed on the dash (when you follow the manual) , can sometimes tell you exactly which part is acting funny to need attention or a replacement.
Drain some oil. Unscrew the bolts that hold the magneto casing on the left.
I have a sneaky suspicious that the starter motor is spinning but you may have lost a tooth from from one of the crank sprockets that spin the flywheel or sprag clutch issue behind the flywheel, but you need to have a look.
If in doubt, have you browse the service manual section on this forum and download the 650 manuals to familarize yourself with the bike’s internals and such.
Taking off the casing shouldn’t be too hard at all, you’re just looking that’s all. Also take pictures of whats behind the flywheel if you can and we may advise if it looks okay or not.
Or it is possible the starter motor itself is worn out. (but you have already replaced this unit ?) so i will look to see if the starter Relay Solenoid is the one that’s causing this behavior.
I do hope the engine is okay, just take care when taking the casing off and putting it back as it has a very thin and sensitive gasket to rips.
I will try to ask around , as i don’t even have a supply chain in canada for parts myself , otherwise i would know more about that country specifically.
Maybe you know what’s wrong with the bike and see if we can help you on the forum a little ?
it may be a shot in the dark, what if you remove the exhaust pipes and replace the exhaust gaskets inside the cylinder head and tighten exhaust bolts to 15 ft lbs max , then see if the smoke stops coming out of the cylinder head.
Then we check again that the smoke is likely a drip from the coolant bottle somewhere, cause we can’t have smoke straight out of the exhaust hole , the exhaust valves would be directly behind that. Then i’d hate to assume we have head gasket failure in the piston chamber where coolant has leaked through internally.
Please also look inside your radiator for anything that looks like “brown milk” etc or strange debris floating.
This is the process of the bike to get sparks and start it.
Key On
Press Start Button
CDI checks rider has held in the clutch lever = Make sure switch is OK or replace it.
CDI checks the neutral light is on = Make sure rear wheel is actually freely moving, since fake neutrals are rare but do happen some odd cases.
CDI checks side side stand switch = bypass this unit, remember what was said in previous comments above from myself and Simon
Now the Solenoid (Starter Relay) clicks to initiate the power to the starter motor to spin it & crank engine.
A bad solenoid or a bad starter motor will make the sparks weak.
Why? They are straining the battery in excessAs the engine starts spinning (cranking)
The “STATOR UNIT” tell the cdi how many revs it’s doing
(Hint, the rpm gauge will be bouncing 600 rpm as bike turns over)Now the “STATOR UNIT” will also tell the cdi how much to spark
The CDI unit, then tells the coils to charge up & fire up 10,000 volts down the HT caps to fire the plugs
You will not see sparks or they will be very dull, if
– Coils are shot
– HT Caps are shot
– Battery is too old (volts dropping)
– Battery is too weak (AMPS aka Cold Cranking Amps isn’t sufficient to crank and power up the bike, electrics etc while engine is cold cranking)
– Plugs have given up (Replace them)Once the plugs are sparking , the engine comes to life thanks to the pistons drawing fuel out of the carbs and creating vacuum for the tank taps & fuel pump to keep the fuel supply going.
If the clutch lever switch acts weird while bike is running, then it will cut the sparks off almost instantly or when dropping to 1st gear.
If any parts above ^ that were involved in starting the bike act funny while its running, the cdi cuts its sparks off.
If compression is WEAK, it will be hard to start.
If valve clearances are “too tight” or “too lose”, it will be hard to start.But let’s cross this bridge if all electrics are sorted out first and its still not starting but i do pray the engine itself is OK.
Also, try this when it is safe to do so please.
Make the bike ready and connect everything and make sure battery is fully charged. Find a private road. Sit on the bike , and have someone push you till you get 10mph on the dash (jogging speed-ish) , then drop to 1st gear , have choke on. and be ready to twist the throttle to scream it to life.
If it starts by “pushing” the bike , then let us know. Don’t jump start a bike with jump leads with a live running van or car as they will 100% burn the electrics of the bikes.
HyosungSpares are known to cause issues for people, and sometimes clients have moaned their cause so much delays in parts and they have the cheek to ask for extra payments called delivery surcharge (after the sale is done) , odd if you ask me. Most FB groups for Hyosung UK Owners & this site do not recommend such sites, same goes with HyoCatalog, .eu, .au , same design, same guy. As various owners can attest to their woes.
Worry not though as i stock the pins at shop including the little grub nuts for it too, all in stainless flavour made on our own UK soil. Just click “Shop” at the top navigation menu or “== top left menu icon == ” if on the phone.
https://hyoriders.club/shop/I’ll give it a shot but lol but I think I read the wrong gauge for coolant the reserve coolant tank is empty any idea which coolant to get I went to halfords and they are useless they don’t know which coolant can be used with aluminium tank
I like Motul Factory Line Motorcycle Coolant, and it is usually already mixed at factory, so you pretty much have to just fill it via radiator (check level) or the reservoir unit.
The picture you uploaded, is that the rear or front cylinder head ? Have a feeling picture is upside down so i am not able to tell. And is the smoke coming through the exhaust header (where pipe joins to the engine block) ?
or is there a leak somewhere externally (have a short ride down the street, then let it idle, look for something wet that may drip on to the hot exhaust pipe causing the puff of smoke. Just be cautious and no need to open anything until the engine is 100% cold, as coolant can easily burst out burning if you open either radiator or reserve caps
Go with what simon says ,
Side stand switch = follow its wires and cut them. Ditch the switch. Join wires at the loom side. Please protect that area by waterproofing with good tape! I mean be ocd about this.Clutch handle bar = follow its wires , the switch will say 0 ohm on the meter when you squeeze on and off on the lever, that means it’s dead. But luckily , i sell the clutch switches, should you need one!
Your fuel tap was posted today , so you should have it soon, we are in yorkshire too just as you are 🙂
When cranking the bike, the plugs will be sparking bright. This means its ready to fire. Dull yellow usually means bad coil, stator (it is also part of sparking due to its pickup sensor inside it), bad HT cap, or plug has broken down.
is it possible to get a picture with your hand pointing to the area where the smoke is coming from exactly please?
It could help narrow down what the issue either internally or externally, could be something as simple as a hose leaking a little through its clamps or something odd but i do hope its nothing to do with the cylinder heads as coolant ofcourse flows around it.White smoke usually means coolant either out of the tail pipe or near the engine, blue-ish smoke is piston rings, so have a good inspection of that too.
Very pretty. Right colour. Love the twin pipes (much better than the single monstrosity cannon on later gvs recently, yuck…, had to to get rid of mine)
Shame about the windscreen, hope you have managed to fix it though, as the rest of the bike from the picture looks like its tour ready even a nice back rest for the pillion 😉
Hi again – thanks for your suggestions. I just thought I’d do everything suggested – sprayed contacts with cleaner & then WD40, disconnected sidestand switch and hey presto! It lives! Thanks again people. ATB – Andy
You are welcome sir , thanks for updating us all , have a safe ride 🙂
Thanks for sharing the pics, just seen them now. Will feature bike in shop galleries 🙂
Hope you get your cush rubbers soon! Drop a review here if you like the chain set!
Uprated Japanese 520 Chain & Sprocket Kit :: Hyosung GT125R GT250R GT125 GT250
