♠️ M77
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The GV sender tends to be a little optimistic sometimes , for example on my GTR it will say full then maybe 30 miles later it drops a bar.
If i am to assume i am riding super economically to get 200+ mile range MPG out of a full 17L tank. I expect 3 bars to drop from full if i use around 5L of it. I am not sure how many miles that is as its been a while since i paid attention to the odo counter lol.
The GV in this case will probably say full until its almost 3/4 left of it, then it should start to move down as the float lowers.
You can always test the fuel sensor like this:
- Full Tank = Ride 10 miles , and go home. Unhook the sensor cable. Test with your meter many OHMS you get from the SENSOR itself.
Report back here. - If you suspect the tank is half-full left
Test ohms of the sensor
Report back here.
Ie. Full was 400 ohms , almost low fuel left was 200 ohms etc… (Example here) these are not actual Hyosung figures. You will get that from your meter,
I will know if your sensor is working or your gauge is fishy or just a harness issue.
Have date with that pocket meter 🙂
Hi I’m in the UK and it’s the round fuel sender gasket I need.not the tap gasket Hyosung gt 125 comet 09. Thanks billy
i am working on this , my plan over the xmas period to mid jan is to stock a fuel level sender on the shop.
I will test it and make sure it works on my donor bikes first.Please keep an eye at the shop around Mid-Jan , if you think there is no update , just reply here and i will respond accordingly.
I am on the hunt to find senders from other bikes to fit a Hyosung GT Carby , wish me luck 😉
JT XRING isn’t too bad , so you should be okay , if in doubt you can always try any RK XRing / EK XRing as my personal preference , there is also other japanese brands like Tsubaki, Kobura. Whatever you do, avoid the likes of TVR, Choho, and them unfamilar chinese brands , they always snap!
For wheel alignment, go behind your rear tyre , kneel down … and so do it like this
- Bike needs to be on paddock stands.
- Make sure your rear axle is a little loose so the wheel moves.
- Loosen chain tensioners a little.
- Pull the rear wheel back as far as you can safely.
- Look inside the “INNER walls” OF swingarm (facing the tyre sidewalls)
- You will see each side a “drain hole” for the swingarm towards the front of the bike.
- You want your tyre to be sort of inbetween them
- ie….
[swingarm leg left] [drain hole] [tyre here] [drain hole] [swingarm leg right]
sometimes a straight long strong ruler helps check the chain is straight also.
- Tension of the chain while it is on paddock stands should be about 15mm when you push the bottom chain up^ (rough guess)
- Check wheel again and chain are straight, then tighten the rear wheel axle to max of 60 ft lbs torque (make sure to use a torque wrench)
If you brake hard the brake disc and caliper apply force on the right side of wheel, that might bring the wheel forward
if you take off hard , the chain wants to pull the wheel on the left side , and vise versa. - I think you get the idea of where i am going with all this
Did my reply help so far ?
What do you use to hold the O rings in place whilst trying to ease the intake pipes back on?
Hey, this is how Korea does things and i am very convinced they put the engine and carb together in to the chassis during production but im sure they have other ways too, until i find more tricks , i will expose it!
Anyways, the manifold orings …..
- Clean the intake pipe grooves well
- Get something similar to PUTOLINE RACE GREASE
- Dress the orings in that grease (no silicone / no instant sealants / no RTV markers)
- Put the oring inside the manifold circle groove
- Find a glass table or table that is very straight.
- Place manifold (oring facing down) on table
- Hold the manifold and press down hard (but be gentle?) so that the o-ring firmly sits inside the groove.
- Hold the pressure for maybe 30 seconds.
Next
Lift the manifold, the oring should now be firmly inside , it should not fall out anymore.
Again, get a little bit of grease, apply a very small coat on the engine cylinder heads where the manifold is going to sit. Just make sure the area is clean.
Take extreme care not to let dust, or debris inside the valves as they are directly exposed in the intake holes of the engine.
Get a very short allen key, and m6 socket cap bolt ready, as soon as you fit a manifold nicely between the carb and cylinder heads = screw in 1x bolt all the way down , while your other hand is holding the carb+airbox combination. It is tricky but you will practise this and it will be easier next time you service the bike.
in my experience (no matter how good i get at this) it will always take me 1hr to put everything back to gether nicely before i start it!
first time i tried years ago , it took me 4hrs and a lot of swearing and an almost damaged intake pipe.
You will be forgiven if it takes you time, it’s okay to be patient 🙂 = After all the real enemy is the frame spar in the middle of the chassis but i guess it was the best way they can design the chassis and cram in everything it needs to function well .
Since it is friday..:
😂🤣 I had to giggle lol
Hey , i got your email , please check it again since i responded to it 🙂
I have got your PM , and i replied to it , so check it when you can 🙂
Welcome to the site!
The Idle adjustment is on the carb itself or it will have an extended cable dangling between the coil cover and left engine crank cover.
if the revs are slow to climb down , it is commonly these (all or one of them, guaranteed)
- Carb is clogged, needs air compressor or ultrasonic cleaning
(It has many holes inside) - Jets inside the carb are also clogged
- Bad E10 fuel ? (If you have E10 fuel, drain it and use E5 forever.)
(E10 will kill the 125cc one way or another , modern cars made for E10 are still better on E5) - Inlet Manifolds have splits or leaking air thru a big crack?
(Spray carb cleaner there and if revs change, i was correct.) - AirBOX is not sitting properly
(air leaks and the carbs are CV, they need a fully sealed up intake system to function right)
____ - Inlet Manifold “O-RINGS” have caked up, allowing air in (click here for visual look)
Click here again, for a quick tutorial on how to carefully remove the airbox out of the carb
___ - Clean your spark plugs
If they are already acting funny or you ain’t sure they are not breaking down
Go halfords and get fresh CR8E
Even if the old plugs work, put them on shelf as backup.
Then start using new ones from here.
The carb mixture is good when it says “all brown” on the plug
(Post picture of plugs sideways and center and top down , so we see how rich they are)Jetting Tutorial? click here
Do each bullet point above first, before you try other parts of the bike , you want to get the above ^ out of the way first.
Then report back as you progress each stage. 🙂
Good luck!
I have another question: If someone has a disassembled 125cc engine, please let me know the length of a con-rod, center-to-center (hole) measurement in cm/mm preferred.
I have stripped engines to sell parts on my ebay shop , but i have not measured parts sizes inside because no one in UK asks me that questions , so its a long forgotten memory!
I will keep you in mind if i ever come across a wrecked engine again 🙂
No the very old style, it just has the two dials (speedometer and revs)
Sorry to keep asking is because the left fork has 2 different sensors for speed (MPH counting) , one is digital (it has a 3 pin plug under the dash) and the sensor is always black.
or you have the old style mechanical version speedo sensor that’s always in grey colour , it has a stiff cable that goes right under the “MPH” side of the dash as to wind it up.
Now with that being said,
There is some aftermarket amazon dashes that are more primitive in terms of function that use a speedo cable hooked to it, it will be some sort of single face gauge
– missing fuel sensor (you won’t know how much fuel is left) but some of them include the little fuel gauge display though.
– missing rev counter (you won’t know the revs ?)There is other dashes that require more advanced understanding of your bike’s wiring and you need to buy a plug like this
Do not cut your harness , as Korea isn’t making anymore of them carby looms, most people that sell them 2nd hand are dishonest (chopped to hell & back)
For example your dash has a “BLUE” 9 pin plug that is a “MALE” , whatever new dash you want to change to,
- learn the wiring diagram from manual
- learn which positions of those wire colours are in the pins of your “Bike harness” blue female side.
- Now the blue dash may have a red wire for power = you can use the red wire on the hyosung side.
- New dash says “Brown” is negative, = you can use the “black/white” wire of the hyosung side.
Just some pointers here, personally i’ve not changed or tried to mess with the oem dashes of the hyosung bikes , they work well lol.
However i will attempt to fit a GTR dash to a GV bike with some brackets and such , i will probably show it off in forum
(warning, not all GT125R dashes have the same looms! Some are crossed)There is always the issue that Korean’s have changed wire colours for certain years of GV bikes , so even a manual isn’t always up to date sometimes.
Some us have to open the dash to see where each wire went. Messy!
the sprockets look healthy for the time being 🙂
Try my fav chain , RK XSO2 520 – And get rivet links also. Costly chain for sure but XRing , and can’t go much wrong with RK Japan chains.
If you have cash , EK XRing race grade chains cost a lot but handle well.
You will also make sure your wheel is absolutely straight (use a beam light, laser style light, or ruller to make sure the chain is straight)
If the wheel is like this / / than | | straight, the chain stretches a lot faster. It also eats away the sprockets faster too.
make your rear shock (if OEM) adjusted at level 5 (stiffest setting) , it makes it less bouncy at the back (chain always tensions on suspension drops & rises also)
Fold that yellow washer again , so that the nut has less chance of vibrating off.
if the washer is damaged teeth inside, please just replace the washer, i’ve lost count people messaging me about sprocket washers when the nut goes missing at 60mph lol . I always fold washer 2x and tap it tight to the nut so there is no gap also. 🙂
If possible, a new nut is always better than an old nut.
Just my late night ideas , hope this helps!
Its mechanical style, bikes a gv125 2007
Does it have an digital screen in the middle (the dash) or do you have a speed sensor under the fork that is “grey coloured” (meaning very old style)
As some GV125s do have a partially digital dash from Korea and a digital speed sensor under the left fork.
Sorry i delayed, i hope the weekend is treating you well!
Anyone looked into converting these from analog to a digital universal speedometer??
Since you have a GV125 Carby , does it have a digital speed sensor under the left fork leg or is it a much older mechanical style ?
In relative to your question using another speedo aftermarket isn’t impossible , bobber converters and cafe racer folks tend to buy cheap taiwan clocks or a single clock , purely for aesthetics but wiring can be a mess!
It means the chain needs to be replace asap. Also look at your front sprocket, if the teeth look like sharp hooks they should replace too.
Or you can also take a clear picture and post in here so we see how it is.
Also how old is the rear sprocket and what brand is it ?
What specific make is that chain too ?
I have personally not changed the sounds of my donor bikes, i must be an old fart, i actually like the sound of the OEM cans that are twins , and drill the baffle hole so that its a little wider, gives me a more softer deep note , its quite nice. I would avoid the single cannons , as they are too heavy and too quiet. If i was to ever change the pipes of my donors, i would get it from silvertail directly.
I assume those are still stock pipes.
If you get a string. Wrap around the part of the headers that connect to the cannons. Ie. String is 38mm end to end , so the headers would be 38mm, you would have to get some kind of reducer from 38 to 30mm, then find 2x long long cans that are 30mm – If the cans rear the back tyre like your old ones, then it should be okay with a baffle hole that is about the size of a 10p coil. This is an example as i have forgotten off my head exact diameter of the old style twin pipes but i do know about the single cannon pipes as thats most common on later GV125s.I believe Amazon might have such cans, ebay is a wild mess of chinese things nowdays. Failing that you could have someone fabricate a Y shape pipe that takes 2 pipes in to one single pipe , then you could have maybe 32mm to 40mm cans that should be about as long to reach the end of the swingarm. You won’t loose too much power and still get a good sound.
Remember though any changes to the air (exhaust or intake) = upjet the carb so the bike doesn’t lean out.
There is a tutorial on the forum on how to safely remove the airbox without damaging the super rare intake manifolds.
I will see if i can find this in the UK trade for me to get it from you. The usual suspects like hyospares, catalogue,wholesales are sites that should burn down to the ground to amount people complaining, so i rarely almost never suggest anyone to shop with them , if it has a blue/white design background, it is usuall the same person that runs the site. Miracles happen, i would guess 10% of people get their parts in a timely fashion, russian roulette here. I have digressed, my bad.
Can you post a picture of your current bike showing the exhaust ?
Some GVs have factory twin pipes and some are a single cannon (2 variations exist also) = Making 3 designs total.
In honesty, the company that makes bolt on exhaust kits for the GV that work well is the LeoVince Silvertail, the bike looses speed without baffle, so best to keep it in.
Due to the nature of the GV having its pipes so short and a massive long cannon or twin long cannons, adding slash cuts is not something i would do, its very loud (annoying loud lol) and the bike looses a lot of power (as it’s too free flowing). However some people don’t really care as they just do it for the “looks” really when doing bobber chop frame cut conversions, so they want things at the back shrunk down more.
The carby GV650 will get away with slash cuts (stubbies) , if the bike gets tuned right. It’s hard to tune the 125 with very short systems. There is a reason leovince kept the pipes long as they can for the GV250 and GV125 models.
Sorry for delayed reply, i hope this gives you some insight too.
You could probably get away with “being creative” to cut inside the stock exhaust to make its hole bigger for sound , and still have some kind of backpressure retain, (The single long long cannon system) , it probably has a lot of stuffing inside to dampen the noise too.
Got bike running over ten mins nice and warm took bother plugs out testesed rear cylinder reading of 144 psi increase of 9 from cold reading however when testing front cylinder psi was 131 the same as the cold test I’d did
Okay, thank you for this, according your PSI i’ve converted them to Korea’s language of using KG/CM2
– Rear is about 10 KG/CM2
– Front is 9 KG CM2OEM limit is 8 or 9KG CM2 (115-130 PSI ish)
My advise for you would be to try and
- Check the valves for tight clearances , as that can affect compression and adjust them.
Korea uses the “Cam Under Bucket” style tappets with shims (that you replace) hiding under the buckets which the cams hit.
Ie. If REAR Valve “A” is exhaust….
It uses 175 shim but clearance on ice cold (overnight ice cold) is 0.35mm (too loose)
I would replace 175 shim with 160 or 165 shim , that should just about bring it to the 0.20-0.30 range Korea says for “all exhaust” valves.
All intake valves are 0.10 – o.20mm max.Optimal for hyosung GT125 (all 125 carb vtwins for that matter) in my experience fixing them is 0.13 intakes and 0.25 exhaust. They puur like kittens after that and throttle is easy, bike starts easier , the bike seems to have maybe 1 or 3 mph extra each gear before redline. - Push comes to shove, be prepared to buy new parts for the piston & rings (as long as the valves are okay and cleaned up, with no signs of a slight bend)
- Replace tensioner (better to go new anyways) and probably a fresh cam chain, it will love you for overhauling it and will give you more good years of running well.
- Head Gaskets (ofcourse)
dont panic at what i said, you’re not exactly at the limit but your engine is getting close to the 8KG CM2 limit on one of the heads.
Hope this helps!
- Full Tank = Ride 10 miles , and go home. Unhook the sensor cable. Test with your meter many OHMS you get from the SENSOR itself.
