♠️ M77
Forum Replies Created
-
Posts
-
Simon is right 👍
FA86 is a very common pad that even your local bike shop should have it. Hyosung has kept the same Grey TCTC calipers front and back for all Carby 125cc twins (That is the GT125 & GT125R)
My recommendations are to use Sintered pads (EBC, Goldfren, those likes etc) than cheap chinese organics tbh.
First time I rode this bike in full darkness and I realized that the headlight was pointed downward about 10 meters in front of me. That and the blinding speedo light made for a bit of a spooky ride! I already played with the speedo brightness, but for some reason it went full bright again. I haven’t had a chance to figure out headlight adjustment on the Naked yet. I sure am infatuated with the sweet power spread of 4000 to 8500. ( in 250cc terms)
Personally i have not had hands on that particular rare headlight as UK commonly gets the roundshape versions (classical look) but speaking of lights, have you had a chance to look behind it for some kind of thumb-based adjustment dial to rise or lower the beam aim or look at the screws holding the headight to the fork bracing , there must be a way to loosen 2 bolts (1 each side usually) then adjust aim, hold it there, then screw in tight. Usually does the trick on my GV Aquilas. The other GTRs i have have a thumb screw at the back as its too awkward to do it any otherway lol.
Since you are in Yorkshire, you aint too far from us if push comes to shove and i’ll sort the motor out but for now lets see what your own fine hands can do, i trust that you will get a breakthrough!
As for picture uploads , I am currently fixing this as i did something silly under the hood when updating site code (developing/custom programming isn’t always fun but i’ll get to that very asap this weekend , that’s on top of fixing bikes everyday lol)
The blue visual tab is there, but does not allow me to add media. I do not see “add media” anywhere.
How about now ?
Welcome to the forum!
Sorry to hear about that but we have faith as the engine is indeed alive 🙂
If you have an Amazon account, get USPRO compression tester or get a mobile mechanic to come over with his compression tester (don’t matter if its for a car, it does the same thing)
Make sure the bike is 10mins hot, then take the spark plugs out , both of them.
Put compression tester in one of the cylinders , eg. Cyl 1 is front engine spark plug hole. Put it there and hard.
Use a “METAL” rod with a curvy rubber tip , dont use a flexi hose because they are known to give false positives sometimes.
Twist throttle to full throttle, then hold it there. Crank the bike for 5 seconds ish max.
Get readings and report back .
We tend to always check engine compression of bikes before address other parts such as carb, coils, electrics and all that comes with it.
The engine is the main key to check to see if its actually healthy
Also, it helps to check valve clearances (if you can or mobile mech?) = Tight or loose clearances make it hard to run right no matter how tuned up the bike is.
It helps to keep fuel lines around 7-9mm max. 10mm is a little overkill to be fair and vacuum lines should be around 5-7 max.
——————————————————————————-
Sometimes , with the 125cc bikes, half its starting issues or idling issues are a result of the inlet manifolds , it is of the utmost importance to take them off (becareful, rusty bolts!) and visually inspect them.
Under the inlet pipes are rubber orings that are terrible because they don’t last long and usually is recommended to replace them eventually.
You will be surprised how much help these little things can do to a bike that’s got a vacuum loss due to caked up old rings or it’s struggling to start.Intake Pipe O-RING (Inlet Boot Seals) x2 – GV125 GT125 RX125 GV250 GT250 Hyosung
Please becareful with intake pipes, the 2014-2019 bikes have intake pipes that are much much soft and prone to splits than the old school bricks of the 2003 bikes (trusted inlets, they are thicker and rubber is better quality). General consensus is that new shape (2014-2019) bikes were a little rushed than the old school 2003-2010 era bikes with grey engines.
It may seems like a little more maintenance is needed on factory new shape bikes but overall they are still wonderful when everything runs right 🙂
I hope i have made some sense but report back as you go along , i will keep an eye on this topic , you got this 🙂
The float seat was a little restricted yes, so it’s a good job you have cleaned out the mesh cone that’s under it. Now the bike can correctly meter its fuel.
Feeding fuel straight to the carb is okay with a clean auxilary pump, just make sure there is an inline fuel filter as you will never know , micro debris may be present in the fuel than our eyes can see.
Was the airbox still connected and fully secure ? And also if you spray under the airbox rubbers and carb engine rubber pipes, with carb cleaner, do the revs change ?
It may explain the slow drop of revs as it’s either
– Hunting for fuel to idle down (clogged pilots / mixture screws too lean / airbox suspicious)
or
– intake manifolds on the engine have a micro leak somewhere
or
– Vacuum hoses have a leak (double check they are blocked hard if not using fuel pump and fuel tank)You can clean the fuel pump yes , but open it. Don’t use air compressor, just a gentle washout with the carb cleaner helps.
No need to spray carb cleaner inside the “silver” hole of the pump , as that’s just for air vacuum.
If the fuel pump is faulty , it will be slow to deliver fuel or if bike is switched off , fuel will leak in to the silver vacuum hole , then leaks in to intake manifold pumps (which is not good for engine health as fuel washes down piston walls and oil is like water and smells very very strong of fuel, this is a sign to immediately flush engine and piston rings may need changing
Which means your compression should be around 150-175 psi hot healthy. It will run at 130 psi but it isn’t ideal, i believe that’s a limit , which means rebuild time soon.
I assume clearances are spot on ? (can affect compression values too)
Or if possible, expect to change head gaskets while replacing piston rings or pistons with rings , this would be an opportunity to really inspect cylinder walls and valves are sitting nicely in the valve head.
So the visual tab is not there anymore ?
Also do you see a button on the left of the reply box that says “Add Media” ?
I really appreciate this , this is on me to fix as i did do something hence i left a yellow notice to logged in users i’m doing something at back end , but don’t worry your feedback is helping me a lot.
I will create a test dummy user and login with it. and test.
If there is any issues posting pictures,
Please try this topic below to test , so i can fix any bugs on the site.Test Topic (Can everyone use this topic to test pictures please)
Can you please explain a bit more please? So i can fix it. I might have caused an unintentional bug when i was doing work behind the scenes .
That’s why i created the below thread as a test topic / image dump test…
Test Topic (Can everyone use this topic to test pictures please)
Can you attach pictures of the plugs if you can please ?
Side view ( so we see threads )
Top view ( to see middle colours )Also have you tried a fresh set of CR8E plugs ?
Also , are you able to test your coils for primary and secondary resistance ? (sometimes coil is bad, and HT caps can’t output enough spark power to plugs at high revs)
Also , remove HT caps and measure ohms of HT caps without coils attached to it. (sometimes coil is okay but HT cap is breaking down / stress)
For the Jet needle , have a look at this tutorial to see if it helps
[Tutorial] How to adjust Carb Slide Needle (Tuning) – Hyosung GV & GT 125/250
Hello,
Set the mixture to 2.5 turns each pot. Take out the pilot jets and look in the sky with them, if light does not shine thru the pilot jets. This could be a problem and also a sign that carb needs more aggressive cleaning (Yes , sometimes CV carbs not just hyosung, but may need cleaning 2x) unless it has been in a good ultrasonic bath + air compressor afterwards (there many holes inside the carb)Also check fuel filter for any debris coming from the tank.
The fuel should be E5 (it may be called different in Norway) but here in UK , E10 fuel is generally bad for bikes (nothing great about extra ethanol)
Also when bike is running, spray carb cleaner to carb rubber intake pipes and also rubber holes for airbox, if any revs change, you have air leak. Sometimes changing “manifold orings” under the carb pipes helps a lot.
If you can, wait for bike to be 10 minutes hot, then test compression for cylinders.
1. Take out spark plugs (both of them)
2. Compression tester (a good one!) inside cylinder one (front engine)
3. Twist throttle to full throttle.
4. crank the bike for 10 seconds and look at compression numbers and tell us.
5. Repeat this for rear cylinder.Clearances when bike is overnight ice cold (that means let it cool down overnight, then check in the morning) all intake valves will be 0.12mm-0.15mm optimal (0.10-0.20)
All exhaust clearances will be 0.25mm optimal (ish) but range is 0.20 to 0.30 max.
Did you also set the floats when carb was upside down on the table ? to 7mm ?
I would also caution that if there is any doubts about the “fuel valve” that’s under the float, its okay to replace it with some rebuild kit or even just get new floats.The float area can also cause big issues from starting bike to full throttle if its not behaving well.
Hola Jose, in what part of Spain are living? I live in Orihuela Costa.
I live very close to you, in Murcia city; and more exactly, I grew up beside the old airport of San Javier (I’m sure you know it
)Sounds like a good Spain meet up is due in your country guys, go set it up & keep the hyo scene alive 😉 , i’ve also noticed more Spain members joining this site too. It’s good to see!
I have been using Yuasa on most of my bikes not just Hyosung , i trust them. I’ve had a yuasa last me 3 icy winters (3yrs) and it was also because the charging system was in good spec (Stator = good AC output , Reg = good DC output)
UniBatt & VARTA are also good alternatives because i have used them also.
MotoBatt ,i’ve not tried them either as per simon, (but i don’t have a desire to try them now though)
14-BS is correct and OEM size as per good Simon!
Thanks to Marcel and Simon. After fitting upgraded stator & flywheel, coils and rectifier bike running better than ever uprated sprockets makes a world of difference
.Hello Dave,
I am very happy for you!
If it is not too much trouble for you, check the stator and reg pages on the shop and go to bottom for “review” section and leave some feedback. It lets everyone know how it actually performs from your own point of view , they can’t just take my words for it 🙂Especially with the 520 chain kit (if you got it from us recently) , leave some review to see what changes it did from stock setup , ie. 1st was 20 oem , but uprated was 15mph (faster) or 30mph (slower but each gear range is extended), or balanced etc etc.
Look after her fella 🙂
I don’t have compression test gauges but wouldn’t mind investing in some. Do you know what size/pitch type fits the plugs? The engine won’t rev to full throttle – it dies if I try get to 1/4 throttle. I am curious, how would the comprssion test results aid in determining an issue? Cheers,
Start it up and keep it running (by any means) until its hot for 10 minutes.
Take out both spark plugs, then fit one compression tester probe in to front cylinder, twist full throttle and press start for 5 seconds to get a reading.
Then wait for starter motor to cool down, repeat again on the rear engine.
Make sure battery is fully charged, as slower spinning cranks will give false positives. (unless starter motor itself
Amazon Prime, get one that says USPRO compression testor. Connect the “straight metal” pipe. ignore flexi tubes etc…
Now hold it down to the plug hole hard.
Welcome to the Club Jose!
Be sure to share some pictures of your ride here
There is some good info on the forum and also a 250 EFi service manual on the forum’s technical section, if something is missing you can also make a new technical topic yourself describing any issue you might be having
If you have pictures , it may help to show us the situation too. Double check EFi service manual in this forum for the 250 has the wiring diagram at its final pages, i think it does , it has been a while since i read it!
At 1500 miles, you or your dealer should have this done on record now or sometime sooner when you get the chance
- Oil Change = Motul 7100 (no matter what he says) , premium oil is better than cheap poundland oil (some garages are known to use crap drums of oil in their workshop to save money as they fill it up on various customer bikes
Or Silkolene Pro 4 or Comp 4
At 10w40 grade only (forever this grade) - Fresh oil filter = Always with every oil change.
Hyosung suggests to change oil every 4,000 km. This is England with 125cc bike commonly used frequently (wether pleasure or work related) with them living higher rpm lives most cases , I in my opinion think 1500-2000 is a good interval to change oil & filter. - Adjust Valve Clearance (this should be on record at 600 mile run in aswell, if in doubt, it’s advisable a garage does this)
- Clutch = If nothing is slipping by now, assume the bike has been run in properly at its first 600 mile life, we don’t need to worry about this unless going heavy duty upgrade.
- 2023 = Change anti-freeze (mileage doesn’t matter).
It is 2 years from the date it started running. (not registration date plate date) - Check bodywork for any signs of loose bolts.
- Brakes (pads wear down eventually)
- Rust on “slide pins” that hold the pads inside the caliper and the retainer springs.
I think these are really the main things to look out for in the time being as the bike is still so young aswell
- Oil Change = Motul 7100 (no matter what he says) , premium oil is better than cheap poundland oil (some garages are known to use crap drums of oil in their workshop to save money as they fill it up on various customer bikes
