Forums 🚥 PiT STOP 🔧 Hyosung Technical Help Issue with hyosung gv 125cc – GV125-S EFi Bobber
- This topic has 9 replies, 3 voices, and was last updated 1 month ago by
Ale.
-
AuthorPosts
-
-
Dec 2, 2024 at 7:51 AM #17312
Issue with hyosung gv 125c
Has anyone had any issues with sitting idle and reves go from 2500 down to 0 then obv stall then go between 2500 revs and go just below 1000 revs checked everything from seals to spark plugs oil and coolant still no improvement no indication to fault being detectected runs on front engine rear starts then goes off cleaned both fuel lines and flushed out oil tank (garage done this) at a loss now normally i help you guys but this has got me puzzled now as my pride and joy sounds like a bag of S***. Garage at a loss too and wont spend anymore time on it, is it because its cold outside or is it dying? Milage 5500 thanks in advance -
Dec 2, 2024 at 9:37 PM #17590
Hey
Check this topic, just incase it is the idle speed controller having a loose/damage o-ring like this guy found out below:Also try the cleaner mentioned in the topic above to clean out the fuel system
Keep us posted// Meditation doesn't mean you have to sit still....
-
Dec 3, 2024 at 9:17 AM #17838
Thanks mate checked them no improvement its firing up it just cuts to the front spark plug and the rear dies out but comes on intermittenly…
Going to recheck the fuel lines but at a loss now as nothing showing on the dash lights as an engine problem…
-
Dec 3, 2024 at 8:09 PM #17864
Then i would assume you have faulty coils ?
Swap the front and rear coils ?
If that’s true, it time to get a new coil and probably new spark plug caps (as yes the coils can kill them) – NGK ones are too recommended,
Since these bikes came out of the factory we always get orders for the rear coil and pair of plug caps. The rear coil fails first as they wasn’t put on properly and the ECU can’t always tell you its a coil problem.
Sometimes you may need to also make sure the regulator is doing “14.2-14.5v” MAX & LOWEST , if it falls outside 14v in any revs , you will face more electric issues and possibly a slowly dying ECU as it’s the most voltage sensitive of all.
Do this with a fresh set of CR8E plugs (yellow box) = DO NOT use “CR8E-IX” (Blue Box) as Hyo 125’s don’t like em. Surprisingly yes the Stock plug or LASER NGK plug is way better for the injection 125cc. Carb Models are hit and miss most of the time.
If it has CR9/CR7 etc = bin them straight. CR8E only.
Keep us posted , we will get to the bottom of it 😉
Just hard for me to give a straight answer online without the bike next to me unless its a common issue we’re already familiar with , unless otherwise in the end, all the checking you did , probably will turn out to be a bike just needing a new part or you missed a small simple thing such as corroded plugs (strip it all down and clean every plug you can find) , unlike Carb Models, the EFI system also checks “resistance” to certain sensors. So if the resistance is too low or too high , it is usually caused by an oxidized / rusted plug that needs cleaning out instead of the actual sensor being fault.
Ie. Tank Level Sensor plug says “100 ohms” , it has a yellow wire (the black one is for ground usually) , if i see the same yellow wire at the dashboard connector , it says 150ohms , i think i have an issue along the wires that rose the resistance quite significantly possibly a bad kink or exposed wire rusting or connector at the dash has water invasion (if its not waterproofed) etc…. Assume that an object attached to the engine has high resistance but the ECU is expecting it to be low when it calls it , it will go haywire sometimes when running , as it’s not getting the values it wants. Hence Simon and Myself in this site usually repeat to owners to try to ensure the harness is as pristine as possible before replacing faulty sensors on EFi bikes. Resistance that is too high on Stators will burn regulators , slowly cook everything that’s connected to the harness unless the fuse blows first, the ECU won’t behave the same anymore, but since you have a DELPHi unit (hopefully, not the 2018 MOTO1 ECU) it “may” or “may not” warn you with an error code at the start “Battery Voltage too high” etc…
I digressed a little!
// Meditation doesn't mean you have to sit still....
-
Dec 5, 2024 at 12:11 PM #17885
the garage i got it from are convinced its the spark plugs but wont order them…
Do you know which type spark plug it is and how to remove it as i cant get a spanner into the rear one front is firing fine but they asked me to run it and disconnect the front one and tbe back should still run?
It cut out within seconds so they are convinced thats the issue?
-
Dec 5, 2024 at 3:38 PM #17886
You can go to halfords and get CR8E as that is the OEM plug for every Hyosung sold since 1999 , so always stick with CR8E no matter what.
Also, while there, ask then for a spark plug tool that fits CR8E plug , get more than 1 tool, incase Tool #1 is being awkward in the frame , get Tool #2 that may be shaped different to avoid hitting the frame or ancillaries attached near the engine.
Do that first…
Ride a little bit , come back.
Send us the picture of the FRONT and REAR plugs = We will know they if the HT caps are on the way out (common! hence we only use NGK Race ones that’s NOT plastic as i would NOT use plastic caps, they will crack!) .
Also have a multi meter ready , and we will send pictures on how to test your own coils to get some hard proof to see if the coils are OK based on readings.
You could do way better than your current mechanics at this rate , good luck!
// Meditation doesn't mean you have to sit still....
-
Dec 29, 2024 at 1:30 AM #18227
I have same issue
Also I was checking ecu mind has Motion mt05 😬
did same model as different ecu ?
I was try to buy one but only find Delphiany suggestions?
-
Dec 29, 2024 at 2:19 AM #18228
Or anywhere I can find wiring for Delphi
-
Dec 29, 2024 at 4:07 PM #18229
Can you post a picture of your ECU?
There is no public wiring diagram as of yet but then again, it shouldn’t be too hard to fix unless the ECU is toast.
It’s best you make a new topic if you can please , so it’s easier to follow your bike alone. 👍
Happy holidays!
// Meditation doesn't mean you have to sit still....
-
Dec 29, 2024 at 9:50 PM #18239
-
-
AuthorPosts
- You must be logged in to reply to this topic.