Oct 8, 2019 at 7:15 PM #3338
I’m new to the biking community and got my CBT about 2 months ago and bought a GT125 which I couldn’t be happier with normally – have loved the freedom and learning how to ride. The problem is that I know very little about bikes or maintenance and am a total n00b! I’m currently rather worried as I’m a new rider and so spluttering scares me a little bit.
The other week someone backed into my bike while it was parked and broke the back brake. I took it to the shop where I bought it and they fixed it for me and said they checked everything over. Ever since though it has done some weird spluttering. I’ve wondered if it’s the cold and wet but then today it’s been worse. I end up in a very high gear to get 30mph smoothly. For most of the week I start the bike in neutral, kick back the stand, switch to first and the bike dies instantly. I need to repeat a few times before it goes. But you can hear the engine spluttering while doing so. If I use the choke it’s a bit better. Is this just normal colder weather behaviour or should I take it back to the shop?
I can also see these two leads hanging loose at the bottom of the bike and was wondering if that is normal? The picture shows one of them. There’s one more on the other side with some form of valve looking thing around it. They almost look as if they could connect to each other? I hadn’t noticed them before and wondered if they’d come loose? But wasn’t sure if to take it into the shop or not. Sorry about the pic quality, it’s dark out so this was the best I could get. You can hopefully see the black hose that is pointing straight down. The pedal shown is my right brake in case that helps.
Any advice would be greatly appreciated. Am one worried girl…
Oct 8, 2019 at 9:48 PM #3341
Welcome to the site and indeed the biking world, may the Hyosung add many miles under your belt!
I will try to guide you the best i can so the bike runs better, it definitely sounds common the issues you’re experiencing especially as we approach the cold season.
Pretty bikes, but Korea could learn a thing or two from the japanese when it comes to electrics, but i digress, let’s get the 1st thing out the way.
1 – Under your kickstand, see if you can spot a “switch” ?
or maybe the previous owner removed the switch and “JOINED” (brown wire and black wire) to fool the bike thinking its still there (Bypassed)
If you said you saw 2 electric wires under the frame, perharps they could be the sidestand wires? = Cut the rusty part of it –> then peel off some fresh wire – > join both wires -> waterproof tape or good tape (lots of it). Voila kickstand is bypassed.
The reason for getting rid / bypassing the kickstand switch is because it does 2 things very annoyingly
– Rattles and causes the bike to cut out while riding
– Makes it hard to shift in to 1st as it then cuts engine off immediately.
For that reason again many of us bin in it and protect the remaining joined wire away from weather attacks (water and electrics dont like to mix)
2. Spark Plugs
You can take one out? If it looks ash black (plug is fouled or the sparking system has gone weak making it prone to cuts and hard starting in the cold)
If the plug says “CR8EIX” – I would advise to get rid of them and use a standard plug “CR8E” or the better “laser” plugs (You can see what they look like at the /shop/ section on the top menu of this site) – Hyosungs dont like the “IX” branded plugs. Stock or Laser wins.
If we can get the plugs right, then our next check is the sparking system so its doing as it says
3. Sparking System (very common on most hyosungs)
Like i said, Koreans could have used Jap electrics but costs had to be cut somewhere i guess!
When you unhook the spark plugs , the “HT CAP” (the long tube that attaches to spark plugs)
That “HT CAP” we call , is another cause of intermittent / random behavior when throttling up or throttling down, when the bike is at hot temps , the HT Cap if worn down/old will start to wane and make the bike move SLOWER (weaker sparking=prone to misfires/pops?)
For that reason , i wouldn’t advise to buy the original Hyosung “Golden” branded HT Caps again, as they will just fail again (lifespan is too wild to measure) and cause problems for the “ignition coil” (more of that below)
Using an “NGK” branded HT CAP will generally make the bike rev a lot better and ofcourse a trusted brand, it rarely fails even under hot temps so you know the plugs will always get the spark signals transmitted to them.
Your garage may not know this but will most likely attempt to dismiss it without testing it on his meters or use the standard again (rather than switching to a more reliable NGK branded one)
It is number 10 on the picture below: (Spark plug “HT CAP”)
So in short, HT Cap = responsible for sending spark signals to the spark plug coming from #7 which i will explain below
4. The same picture above ^ , at #7 these 2 circular shaped coils are attached on the frame 1 behind the oil cooler and 1 under the airbox of the bike. This item is more crucial than the #10 HT CAP
The coils are probably #3 on the list of parts many owners change to use better coils on their bikes, I too also suggest better coils.
The ignition coils are responsible for sparking your plugs. The bike won’t move anywhere or be rideable if either is dead. Signs of a failing coil are always these
— Hard starting in the cold / takes ages to warm up
— When engine is up to hot temps = it is prone to cutting off while riding
— Throttle feels sluggish or heavy (ie. as if on a leash)
In conclusion, a healthy hyosung will benefit from the NGK HT caps and better coils, winter mornings will be better for you and it also.
5. Regulator (see #5 on pic above) – Probably the #2nd item that causes electric woes once it starts to wane. General consensus in the community is to change for a better one
I think you can check this yourself and change it as it is located on the LEFT side of the rear bike, that giant square block item with 3 yellow wires + 2 red/black coming out of it.
The regulator is what charges your battery and supplies running electricity to the whole bike, so its crucial this object works optimal , otherwise just like number 4 ^ (coils)
– Starting will be harder (as if battery wasn’t charged?) (slower cranking is a hint)
– The lights will be more yellow n duller until you rev up
IF LIGHTS GO BRIGHT if you increase revs, its time to change it.
– If the “DASH” spazzes out or gets very dimm while trying to crank start (battery hint)
If you have a multi meter at home, I can easily explain how to test your coils , HT cap, regulator voltage – You might save some mechanic bills if you’re confident to do some self diagnosis and also some mechanics don’t always check everything (always rushing / taking shortcuts)
Back to the regulator, if you start your bike and rev up to 3000 revs, your battery should say 14v on the multi meter switch to V20 (20 volts)
if there is any “12.x – 13.x” readings = regulator is toast or dying away so bike will generally perform poorer and these things always blow up when they die. It’s very cheaply made sadly.
if its beyond 15v in any revs = change right away. Once it hits beyond 15v the battery will cook and blow. Hyosung has been through various regulator designs on their bikes, they are all rubbish if i am brutally honest. When i service customer hyos, i check electrics starting with the regulator & battery so i know the electricity supply is right, before attacking other parts of bike.
These things i mentioned so far , you can see them at /shop/ section then click the “pictures” in full view , those bikes you see are when the customers fitted the parts by themselves , they were a literal “swap and go” kind of job, so no business about chopping up things / botch jobs lol etc…
Ofcourse the mechanic can always fit them too. It is better you had the replacements in your hands and tell him to fit these , than him trying to use whatever he finds in the shop that may not always be suitable (then problems resume again)
Okay, so lets move on to fueling. = Any form of bogging / cuts / poor riding up hill can be a sign of a clogged fuel system. Let’s try the 1st trick.
—–Fill 3 bars of fuel max (maybe £2-3 in the tank) or your display should show 1/4 or 2/4 of fuel.
—–Go to Halfords / Asda / Poundland = Get 2 bottles of RED “REDEX”. (each bottle is called 1 shot)
—–Fill 2 shots (2 whole small bottles) of it in to the tank , ride hard until bike is goes in to the “RED” (if speedo is mechanical) or “1 bar” if dash is digital display, then put fuel normally.
The bike “should” be a tad bit better than it was before. It is sort of like a “mini soft fix” to unclog the fuel pipes , and your carburretors (huge silver thing under airbox). the redex will burn away as you ride.
To improve fueling , hoses are changed to colder braided ones (hot engine thats why) and stock pipes must be changed after 2-4yrs or they rot inside (hence clogging debris flowing down the lines to the carb!) – On top of that , the filter is quite tiny , we change to the large ones almost 3x the size, such huge filter best trap a lot of particles for a long time even as far as 10,000 miles that way you will have a less clogged fuel system feeding your carbs (carburettors)
The carbs ==> then feed clean fuel to your spark plugs! – So we are attacking “fuel” and “electrics” at the same time because they are as good as each other (air / fuel / spark)
If the situation improves when the fuel +vacuum pipes and filter was beefed up (tutorial here) …. (and also here…) , the bike should start better and feel a little bit throatier at top gear (less excuse to starve of fuel with bigger lines)
Looking at those 2 links, would you be familar with the process ? if not , a mech can change the lines and filter if you supply them to him. We wouldn’t want cheap lines just to change in 2yrs again, the braided lines will last you 10 years, so you will pretty much forget em once fitted, should i say!
Okay lines done, let’s make sure the carbs are the last resort. If what i say above ^ has been done, the last thing would be your carburettors needing a clean (from old particles clogging it)
At the same time you can upgrade its jets so it improves its fueling (tutorial here…..)
At least that way if a carb needs cleaning , it can be beefed up a bit at the same time just to improve general cruising or top gear riding. A mech can do this if you supply jets, but i must stress HE MUST NOT “change the hidden mixture screws” whatsoever unless he is a professional carb tuner (not just some amateur) – Koreans don’t even tell in the service books to touch the hidden mixture screws (they are fine for the 125s almost spot on tuned at the factory)
Only “Main Jets” change. “Mixture screws” are hidden away usually , so you won’t even to worry about them anyway.
Now, we should have a bike that splutters less as if trying to misfire or bogging out of fuel after a fast long sprint etc..
Fuel out the way now!
This one should be a little easy and a fast checkup, – Lift your tank up and place a long fat object under the tank bolt hole and “yellow frame” plate that it sits on or someone to help hold it up for a moment.
—Disconnect the “2 pipes” under the tank and “sensor wire” (yellow n black plug)
(see one of the tutorial above which has pics of tank removal)
(use the same 2 links i shared if unsure which hole the pipes fit back on , under the tank)
The tank sits away somewhere safely, now next , unscrew the 4 screws on top of the airbox that mount the air filter. Take it out.
If its DARK yellow towards a brown ish tint = it’s likely dirty (remember we want no particles escaping in to the engine) – you can change it now . They last about 6-10k and discarded for a new one. = Bike responds a LOT better simply.
A clogged/stuffed up filter will just make it hard to accelarate sometimes and makes throtte action problematic (its either bogging low down then it surges forward like a rocket at high revs etc..) A fresh filter generally makes the engine run a bit cooler (more air is back to normal) and your spark plugs will be less sooty as they need good air to burn the mix fuel too.
Less air = more unburnt fuel likely escaping = pops/gurgling/ etc.. in some senarios.
If the filter looks like WHITE GAUZE material inside , it’s trickly to clean it because it has a snorkel-plastic inside (also a restrictor,but i digress) – Air Filter Cleaners for bikes generally clean the foam and gauze material filters and they also get some oiling spray afterwards – the gauze material of the filter traps fine dust better when its sprayed on after a clean , but filter has to dry first. then oil it a bit afterwards.
K&N is also gauze material, its red because of its oiling too (done at the factory) however K&N filters are also classed as “high flow” or uprated meaning they flow way more air than a stock filter does —– this requires the carbs ^ to be upjetted (see carb talk above ^)
A clean standard filter is better by far over an old uncleaned one or badly clogged.
“YELLOW” filters can’t be cleaned as they are made of paper = Hyosung switched to GAUZE material filters since 2010 i believe (and they flow better than the old style yellow ones)
Right then!….. now have done “spark / fuel / air ” related stuff to the bike , i should expect it to behave way better than you say initially and definitely suggest the good TLC before winter comes – No fun doing stuff in the freezing cold lol. Autumn is still warm i guess!
Last shout…… If a battery is 2yrs old or more – A garage must test it that it CAN hold charge and doesn’t DRAIN so soon (makes it annoying to run = hint , lights flicker at idle speed)
Battery size is 12AH – Brand to use is YUASA YTX-14BS or Varta 14BS (german) or good 3rd “UniBat 14BS” – Any other brand, walk away, most have rubbish cells that cant handle 2 winters even. (Smaller eg. 7ah are not ideal but some have fitted them to save money purely)
When daylight comes back, maybe you can show us better picture of the pipes / wires you speak of – but i was guessing they would be on the left side of the bike frame one of them being a brown color wire going towards kick stand. (switch removed maybe last owner forgot to bypass it properly) either way the switch is annoying so bypassing it is a good idea.
Speaking of bypass = Ensure the cable from your “CLUTCH LEVER” going in to the frame isn’t frayed or kinked etc…
Inside the handlebar lever = the CDI will sense that you pulled in the clutch before starting/or bike is in gear.
The clutch “switch” is inside the hand lever itself with a wire sticking out going to inside the frame, if the switch is faulty , it will for sure cut the bike out while riding or instant in to 1st gear
I think i have covered as much as i could ? for you to check yourself – I could go on , but if there is something i said not making sense let me know! – Excuse any grammatical errors, typing away as my thoughts flow out lol.
Lets see how you get on , keep us updated.
// Meditation doesn't mean you have to sit still....
Oct 8, 2019 at 10:48 PM #3342
I think my brain just blew up! That’s a lot of good information. I’ll need to take my time to try to digest it all, and find out what bits have been done to it or need doing. I may print out your list tomorrow and try to run through it step by step if I can to see what bits are on my Hyosung. Then again I’m not even sure how to take a good look at the engine? It’s such a heavy bike (for me anyway) and I only have a kick stand – not like a normal bicycle that I can just tip upside down.
It had 1k miles on the bike (2016) model when I bought it 2 months ago (which was surprising by the way – but still loads of tire thread so seemed legit), I guess nothing has been changed on it and it’s just factory spec but will have to double check.
Do I need special tools for all of that too? I don’t really have a support network here or know people who ride who have tools. I think I own a spanner, hammer and a screwdriver or two! I won’t lie it’s a bit intimidating this list am a bit scared of screwing it up. I may field questions for each bit when I get going.
I think it is still under their shop warranty for now so I may get them to check these ‘loose’ hoses out tomorrow to tell me what they are.
Thanks so much again, I have loads to learn!!!
Oct 9, 2019 at 11:40 AM #3346
Here are some more photos of the hose by the kickstand which seems crimped off.
I really don’t know what I’m looking for in terms of the ‘switch’ by the kickstand either, cannot see one. I’m wondering if someone did modify this bike, but the shop told me it is factory spec? Or am I looking at the wrong thing?
The hose in my hand on the other side is crimped off. No idea what it is for. You can see it in the left in the first picture just hanging down. The one on the other side is thinner and is just an empty hose tube from what I can see. Does it let things out?
Oct 9, 2019 at 1:31 PM #3348
Hey, take your time , my bad for the brain overload😬. Had to cover the common culprits that may be part of issues you describe. If there was something i said you need to check, I can elaborate more.
As for your tools, well a digital multi meter should be next on your list (halfords, etc)
& when you’re feeling more confident to take down some small thing , you can expand your tool collection. Usually Argos/Halfords tend to have 3-figure assorted tool set to cover various things (eg. 120-piece tool set etc..)
Hell in 2020 you may be doing your own oil changes, if not already! – Saved some garage bills have we? 👋 Plus you have a Naked bike with less plastic coverings so life is easier for you lol
Your pictures today are much better, so start with the main culprit of cuts. Stand Switch!
It is number 6 on the image below with a long black trailing wire jacket along the frame
There is 2 wires inside the black jacket.
We cut #6 away and put it in bin.
Then we peel away the black sleeve tubing containing the 2 wires… those 2 exposed wires get joined. Then lots of tape cover them and hide it away.
Now we have got rid of the switch and bypassed it (fooling the bike, so it never cuts again)
But ofcourse make sure the stand is up before setting off or be sat on the bike before starting it 😉
That tube with a “slit” at the end is nothing to worry about, it faces the floor. It helps the engine dump away excess junk (ie. someone messed up his carbs , or too much oil was in , or engine is breathing away oily mist in to atmosphere near ground)
You rarely need to pay attention to it , except just general cleaning around it so mud doesn’t clog the port/slit.
If you also go to the right side of bike but directly behind the rear engine + red shock spring
U will see a long slim tube coming from the FUEL tank going down to the ground
This is called “tank overflow” – (overspillage, overfilling, etc… excess fuel is dumped away in to atmosphere/ground)
The only thing to make sure is that no exhaust pipe at the back is touching any pipes (fuel vapor!) If its a new bike, it is already probably guided down nicely away from the exhaust anyway.
You are correct to say “let things out”, pretty much “excess liquids” the bike doesn’t want.👍
There is a 3rd final hose that points towards ground, it is hidden somewhere along the right side of the frame but they end up at your silver carbs in the middle of 2 engines.
The carb will “let excess fuel out” to the ground / atmosphere (like the tank & engine^)
Only happens if the bike falls to the side or someone messed something up inside the carbs causing it to flood itself inside.
Since your bike is 1k old and under warranty, you can digest what i said in prior replies, as some kind of bullet list then probe your mechanic to confirm the bike’s history, its service records, test records etc…
Actually, use this list then you will be happier to ride it and bike should be on spec , nothing out of place. Some things i will quote many will also agree as the general consensus to change outright. I didn’t cover every single nook n cranny but just the stuff to do now (more in 2020)
Tyres = #1. Too crucial. Change to Michelin Pilot Street Radial, Michelin Road 3 or 4, Bridgestone T30/T31 , Pirelli Angel GT. Put simply , if you see “SHINKO” on your current tyres, assume they are suicide bricks that can’t be ridden in the wet, nor they inspire confidence. As rubbish as chinese rubber lol. So i stress this not because its a heavy bike, but damn, it will slide on rubbish tyres in the rain, doesn’t inspire much safety does it in a rain session!
Michelins are my top choice always.
Engine ===> Valve Clearances (he must prove it was done, regardless, engine makers said to do it at 600-1k, then every 4k)
Oil ==> Strictly “Motul” or “Silkolene” branded Ester oils go such a long way over rubbish cheap oils. If he says “it doesn’t matter” , ask him what does he know about oils lol. The Motul/Silkolene Ester oils are premium meaning it will last longer, your clutch tends to like it.
Oil change is every 1,000 miles (1500 is a true limit but its 125cc, so it has a harder life already, changing at 1k is more ideal)
Choices ==> 10w40 Grade or 10w50/10w60 grade (best) == it must always start with “10w” only. Walk away if you are suggested a “20”. The oil names are:
Motul 7100 , Motul 300v, Silkolene Pro 4, Silkolene Comp 4, , choose whichever suits your budgets.
Bike takes 1.5 litres, so you will get 2x 1L bottles.
Rarely do i trust the oils used by mechs , as they are simply a huge container of cheap oil used across many bikes (cost saving) , better for the customer to supply their own oil and whatever other parts need replacing on the bike. Sorry if this sounds like some kind of dissertation, but personally i spare no expense to good tyres and good oil. I’d like to be home safer and with an engine that isn’t drinking black blood lol ( Silkolene stays Red 😉 )
Oil filter is always changed too it is on the right side of the engine casing and it says “OIL FILTER” , easiest job. 3 screws out, change and go! (tap here so you see what i mean)
You want clean filtered oil circulating
Fueling = As before in my past replies, perharps the mech will confirm the fueling side has been thoroughly cleaned up (lines, filter , and carbs = no more excuse for clogs/bogs/hard starts)
He will put it in books for your history and see how long it behaves good for, hopefully all the way in to 2020.
Brakes = Goldfren carbon ceramics are great pads, they absorb some of the heat made by the brake discs so the brakes dont always need to feel delayed or spongy (helps in the slower wet braking too). or EBC “HH” branded brakes . The brake calipers both front and rear use “FA 86” code for the size of pads, very common pad, so most bike shops will have it on the shelf outright. I say this as cheaper chinese organic pads make an ashy mess (brake dust) and they tend to squeel and the like . The claim “it doesn’t matter”, walk away when you hear that. Brakes are MOT anyway, so your tester checks how the disc looks and where your pads are (if too worn down)
Battery = Outright, if there is a battery smaller than 12ah (printed on it) , change it . As i was saying from previous reply, smaller sizes don’t help in winter, old batteries can’t handle the cold, so they are just weak overall. It will annoy the bike always trying to charge it up. It has other places to feed power to lol. So a battery can be swapped out by you even. Just pop off the rider seat and look at it.
Electrics = As its under warranty , aftermarket products may void it unless the dealer is cool & knows hyosung electrics very well. So if it is 1K old, I will give the benefit of doubt that the bike is too new to start failing its electrics now , but it can’t hurt to get confirmation readings (he will write down his findings) – He has to as bike is now at 600-1000 mile mark, part of servicing involves checking electrics so everything is behaving as it should.
He can confirm these?
– Coils ===> under 6k ish ohms from Chassis to HT Cap (or investigate/change)
– Regulator ==> showing 14-15v at the battery around 3k revs (any 13.x/12.x = change it)
– Spark plugs ==> Not using “CR8EIX” (Hyosungs hate it, even if other brands like it)
Crucially at the electric stage , just improving the spark plugs alone can pay off well, and you can do this , if you go under your seat there must be a long metal tube thing, thats a “plug removal” tool or can buy one (?)….. I’d suggest getting Laser plugs, they last 50k or 2yrs whichever comes first if your carbs have been cleaned (=cleaner fuel)
If there is something you’re not sure of, you can always take a picture of it or I will find a cartoon diagram to explain what it is. or can make a short technical list and your mech will say yes or no to each point , then service what needs doing etc…
I was digressing as you mentioned its 1k fresh, that’s a young one for sure, so wanna make sure its off to a good start. Most newer customers bikes i service are well in to 4-7k already lol. Then i start to do major things to them.
Hope what i say helps today! Ride steady out there….
// Meditation doesn't mean you have to sit still....
Oct 9, 2019 at 7:59 PM #3349
I went to the shop and spoke to my mechanic who bypassed the switch for me on the spot without charging me 🙂 . Instead of taping he even had a really nice wire cover that he put on and crimped so there’s no chance of the wet getting in it.
He was really good about it. I took her out for a ride and even the ‘spluttering’ which is what I called it has stopped and had no more gear problems. Smooth as anything now! I think the engine was just continuously about to cut out cause of the problems with the kickstand.
I noticed the oil filter sign and it is as easy as you said. I pointed it out to the mechanic who even offered to help teach me how to do it when it needs changing next in another 500 miles or so. I can just bring it to him and we’ll do it together which is great. I’ll wait with the tires until they need replacing I think just for costs. I’ve already had to do an emergency stop in a downpour and I find that the back wheel slides left and right, but I have very good natural balance so I don’t tip over if that makes sense but that has been going straight. I’m not good yet at really leaning into the corners so even in those I think for now I’ll be ok, I also mostly ride here in town at 20-30mph so feel ok for that now.
I’ll work my through the list slowly!
Oct 9, 2019 at 11:47 PM #3353
Happy for you,
Looks like today has been productive and you have someone who isn’t dismissal, also im glad he protected the bypass from weather attacks.
You can see why it’s the #1 annoying electric thing we first discard , now the bike should behave as it should have without it being temperamental (lol)
Hey take your time, it’s a fresh machine , you will take care of it and do what needs to be done in stages.
If its 1K. he would be correct to say by 1500 oil change time (by 500 miles you said), although after that then ideally every 1k. Oil and filter is replenished.
Ride steady 👍
// Meditation doesn't mean you have to sit still....
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