Bike won’t fire cold but it fires once working = GT250R 2012
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Bike Model = : GT250R 2012
Hey guys
So long story short my GT250r i bought with 29k kilometers isn’t firing when cold after i took it to the mechanic.
Spent 800€ at the guy, he did a bunch of stuff from new battery (ytx14bs), new coils new plugs new headlights, cleaned valves, adjusted clutch adjusted brakes adjusted suspension, previous owner had it lowered for and suspension at max for whatever reason (said he had it set up for racing). He also fixed a bunch of poor wiring, etc.
However the bike doesn’t fire after looong hours of sitting.
Initially all I did is move the bike and wobble it a bit and it fired up. If i shut down the bike immediately after and tried firing up again, it would fire up straight away fine and healthy.
Ive put 200km on it since it went to the mechanic but i have to manage the bike like every 3h, i go fire it up or else it wont fire up hours later when i need it.
Last time i rode it I had to push start it (the wobbling and moving stopped working), but the bike runs perfect, better than before (i put 3K km on it before it went to the mechanic).
It went to the mechanic cos it took a bunch of water right under the tank and didn’t fire properly after it (one of the cylinders wasn’t firing). He fixed all of that but yeah now bike just won’t fire if left sitting for hours (sitting overnight for example).
I’ve tested a bunch i somehow magically get it to fire up by wobbling and moving it, i wont even ride it and 2-3h after it fires up again no biggie, its not even hot or anything.
Battery is fine i checked it sitting and it’s at 12.2V healthy.
Fuel pump primes everything works, no FI light but it just doesn’t fire up at first after hours of sitting. It’s so weird and is bugging me off
Any help is appreciated 😁
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Does it spark well when its ice cold for hours ? Check your coils if possible ?
To start the bike we need 3 things = Stator Signal (crank spinning) , Injectors firing and ignition coils firing the plugs nice and bright
I would be suspicious of the stator ? It is easy to put the wrong one too or that the pulse sensor seems to hate the cold (ECU thinks dead signal recieved = cut sparks)
Your wobbling = Find out what cable wires are moving and check them (eg ? Clutch Switch sensor, KillSwitch Plug under air box could be covered in crud/dirt ?)
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Hey Marcel,
Spark plugs, caps, coils, battery are all fresh new. He tested them twice after installing and on different days after riding & rain exposure, and they’re healthy so can probably rule that out, although they will probably be triple tested.
He also messed with the clutch sensor and the kickstand sensor as both were randomly activating and shutting the bike off and that’s also fixed now.
My main suspicion is also this: “I would be suspicious of the stator ? It is easy to put the wrong one too or that the pulse sensor seems to hate the cold (ECU thinks dead signal recieved = cut sparks)”
Problem is that if it really were the stator, then I wouldn’t be able to ride it at all? I’ve also read about the CKP, although its weird because this has never been a problem and suddenly is, right after it comes from the mechanic, I guess that’s bikes in general 😀
There was also some weird stuff done to the bike, especially the alternator, apparently it’s got some bigger material in there, mechanic says the regulator its using is from a 650 like a vstrom. That’s not the main issue, there was some wiring disconnected that was meant to be connected to the battery’s negative node, and they’re also doing some weird bypass straight to the battery that I did not understand unfortunately. All I know is that he reconnected that wire. I’m still a greenie on this bike world but might the regulator be slowly draining battery? Anyways I’ll leave the regulator here.
P.S: The mechanic test rode the bike after he fixed it and the guy was truly mesmerized. Said its much funnier to ride than other bikes in the category like the bmw 310r or the ninja 250 (it was the first hyosung he rode) so yeah that was cool to hear lmao
Anyways thanks Marcel, never forget ur a legend!!
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I hate to be the legend that upsets you but slowly , investigate the stator (drain oil first) – I believe it would be a good idea to get a new good stator.
Also replace that regulator. never trust a regulator that is not a real japan mosfet shingden on EFI bikes because there is too many sensors that depend on a very stable voltage.
Stator = I had a 3 customer bikes in the last few years where stators where the reason bikes did not cold start properly and i had to replace everything else on the bike, i did not realize the stator was fault.
Bike 1 & Bike 2 = Wrong stator fitted.
Bike 3 = Pulse sensor went haywire.A carb model will get away with a bad stator and bad regulator for a while (in limp mode) as it’s just only worried about a CDI unit.
So yeah, lets go to the stator and regulator unit. Keep your old one for purely emergencies but i doubt you will even need to worry about it as a true mosfet shingden regulator will last years and years and years , I still have the same one my bigger GV EFi model. Everyone knows getting a Daewoo ECU for the GV650/GV250 is like going to war! No gold to be found for 99% of the earth. The regulator was needed to be upgraded even with an inline fuse to avoid electrical spikes to it.
Bike wont start without a stator anyways , it’s the 1st object the bike looks for before triggering anything else. If it starts when warm , but refuses after its cold , check how much battery has drained (if 12.9V in the morning , then check overnight how much voltage was lost)
Get your mechanic to do a “LOAD” test on the battery too using a special Yuasa Analyzer (usually mechanics or garages keep this)
& yes , Hyosungs have a character of their own! Must be a Korean thing!
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Hello everyone, hello Marcel,
So a month and some days passed and the bike is back into my hands. Mechanic replaced the regulator (funny story, he actually shipped the OEM regulator from Korea, unbeknownst to me, i would’ve obviously told him to not do it based on Marcel’s innumerous warnings, but that happened, the regulator fried like 5 minutes into running lmao, he’s also having issues with the warranty claim), anyways, he got another regulator that doesn’t heat up at all, fixed some terminals, fixed some dubious wiring, and mainly, did a LOT of testing. he also wirelooped the kickstand sensor, just to be SURE.
He was basically starting the bike multiple times a day for a week. Cold starts, rainy cold starts, inclusively rode in the rain, something he hasn’t done in years, all for the sake of the bike, let the bike sat in pouring rain. It seemed like the problem was done.
Bike came to my hands last Thursday, I had ridden it that same night and let it sat overnight.
Friday morning, you won’t bloody believe it but the goddamn thing didn’t start. I called him and he came over right away to witness this thing with his own eyes, it didn’t start up either on his hands. Not until he turned off and on the killswitch multiple times rapidly, did it start, lights fully off to allow for maximum voltage delivery to the starter motor & etc. Fuel pump primes loud and healthy. Starter motor cranks like usual, tachometer pointer goes up with each crank.
We thought okay well the killswitch has gone bad or its wiring.
Next morning, it won’t start up yet again, and won’t start up either with the killswitch trick. On a last completely desperate attempt i start opening the throttle and you best believe that thing started right up.
Few morning after, same thing but a bit roughier, it first only started on one cylinder for a few milliseconds before hearing the second cylinder kick in.
Morning after (today), it didn’t want to start even with the throttle trick, i had to move and wiggle the bick a bit on its suspension and it uncoughed up (while throttle was open, and ignition pressed).
My bike has demons!!!!! Can’t wait for tomorrow when I start it up again, might have to flip the bike upside down to get it to start.
Thing is, once it fires up, it runs perfectly for hours. I rode for 2 full uninterrupted hours on Saturday (2days ago), it rode just fine just perfect. Once the bike fires up, it fires up consistently for the next couple of hours, until it sits overnight.
Mechanic checked the stator like you asked, it seems in good shape.
I now have a fully new eletrical system basically. new headlights new regulator new battery new coils. got new plugs new caps, whole bunch of new fixed connections. But the thing still wont start, I guess we focused too much on the eletrical but the issue is something mechanical.
But the main thing that scratches the back of my head is why the hell does it fail on my hand but not on his?? he started the bike easily 20+ times in a week, including 3 nights asleep, and it started up. It also seems to prefer starting standing vertical and not on the kickstand, so much so that it doesn’t fire up on the kickstand.
Its something tricky thats position based, has to be, its the only explanation, also read about IAT, fuel injectors sticking closed when cold, fuel pressure in the rail can bleed off or the injectors themselves gum up. The issue is clearly something that slowly gets bad with hours passing, but then again, why did this not happen at the shop??? Grrrrrrrr!!
Sorry for the long post, but this is really getting on my nerves haha and my wallet is hurting 🙂
Thanks everyone.
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Hey you mentioned, sometimes it has starting issues when on kickstand, is it bypassed ? and if yes , remove the bypass to check if the wires had internal corrosion, it happens sometimes with these new Gen RC machines.
Also check your tilt-sensor or replace it ? if your mechanic can use a tilt sensor from another bike, it is also called RO Sensor (Roll Over), bike maybe thinks you fell down ? so it shuts off sparks & starting, it can happen, I am not sure it is a good idea to bypass it (heaven forbid the bike falls in the garden and it is still running!)
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