GV650 FI 2002 – REGULATOR / RECTIFIER Instant overheat

[Zargoo]

Bike Model = : GV650 FI 2002

Hello guys,

So i am working on a gv650 FI that has this weird electrical issue. The problem is that the RR nearly instantly breaks. What happend is after installing a new RR it charged for the first 30-60 seconds on idle after that it instantly dropped to ~12.6V aka the battery voltage at that time and did not charge anymore, also it was boiling hot to the touch. Now this was with a oem new RR. After it cooled off i tested the RR in diode mode with the help of the Service manual specs and it did not pass and was now shorted. It also did not charge anymore after cooled off.

After that as the oem one was quite expensive i bought a cheap ebay one to investigate, now with this one the same thing happens but it seems to break after a longer period. After installing it in idle it seemed to work, after revving once it instantly stopped charging and like the oem one dropped to battery voltage. Now the thing here is as i turned of the bike instantly the ebay one still seems to work after cooling off. It also passed the diode test.

Now i tested a lot of stuff. First measured the magneto phases all pass have the correct resistance and no shorts. Also the coils where inspected visually and had no visual issues.  Testing no load phase to phase i get at max rpm around 120-130VAC peak. Now the resistance on the RR DC output site seems to be fine as well, the ground has a vdrop of 500mV but this should not cause it to overheat so quickly. Regardless of that my theory at that time was that the issue has to be on the DC site, e.g. bad battery or wiring, because if the RR DC site losses positive or negative for even 10ms the battery disappears as a load and the stator’s constant current has no where to go, causing instant destructive voltage spikes inside the RR that kill it within seconds.

Now as this could have been a battery issue i checked that with a tester and it passed all test with a internal resistance of ~12mOh which is very good, and also makes sense as this was a battery for a known good bike that was similar to the oem one that was inside it before.

As the charging system does not have many components aka 3 Phases -> RR then positive site goes RR -> 30A Fuse -> Bat + and negative site is RR -> Bat – the issue i assume has to be somewhere in that path.

But now one of the interesting parts and also the reason why i am looking for help, to verify if the issue is really from the bikes wiring i wired up the RR DC output directly to the battery with a 30A Fuse holder. And even with this setup i got the same issue. The setup was 3 Phases -> RR ->DC Positive -> 30 A Fuse -> Battery positive and RR -> Negative -> Battery negative

And even with this it seems to be the exact same issue. Now as this setup basically eliminates any bike electrical wires the above theory does not seem to hold up and the issue would be back at either the Magneto or Battery which potentially falsely passed the test.

Looking closer at the magneto, I don’t believe it can be the cause. A permanent magnet stator is a constant-current source its output current is fixed by the magnetic design, not by the load. Shorted or damaged coils can only reduce the charging output, they cannot magically produce more current or voltage than the stator was designed for. So a bad stator means less charging, not more stress on the R/R.

The battery could also be a suspect, but I doubt it. The battery currently installed was pulled from another bike where it ran without issues, and it tested good on a battery tester at 12mΩ internal resistance well within healthy range. I’ll swap in a freshly charged battery from another bike to rule it out completely, but I don’t expect that to change anything.

One thing I haven’t been able to verify yet is the actual charging current. The stator has a fixed constant current based on its magnetic design if a previous owner installed the wrong stator, the charging current could exceed what the R/R is rated for. Though as the 30A main fuse never has blown this is also highly unlikely and based on that fuse ruled out, though as my current clamp broke i can not yet verify this.

So I’m backed into a corner right now. I don’t believe a new stator will help the physics don’t support it being the cause. I also don’t think just throwing another R/R at it will solve anything. The OEM replacement already died within minutes, and the cheaper eBay unit is only still alive because I’ve been babysitting it every time the SCR regulation fails and the charging voltage drops to battery resting voltage, I immediately shut the engine off and let it cool down before the damage becomes permanent. It’s not actually working, it’s just surviving between thermal failures because I keep intervening before it fully dies. And I’m not willing to spend even more money on an expensive MOSFET R/R only to watch it suffer the same fate as the OEM shunt one that’s already a lot of money lost with no answers.

Now the above theory i had seemed to also be supported by the picoscope results i had but as explained above this theory might  be wrong. But still below in the second reply are images of the waveforms as this could help anyone reading this find the exact cause or see if these are expected waveforms, if needed the psdata files can be provided as well.

I would appreciate any ideas, help, or experiences from anyone running a known-good Hyosung charging system. Reference waveforms from a healthy system would be especially valuable, as it’s possible that some of what I’m seeing on the scope is just normal behavior for these bikes as I have no known-good baseline to compare against and this whole issue might not be a issue at all and just the RR turning off after overheating.

And of course thank you for taking the time to read this rather long post and issue description.

[Zargoo]

The channel layout for all images below is the same:
CH A – Probe on Y1 wire from the Stator uses a 20:1 attenuator
CH B – Probe on RR DC + output
CH C – Probe on RR DC – output (BW wire), with the probe ground reference clipped to battery negative. Since both the BW wire and the probe reference connect to the same point (battery negative), this channel essentially measures the voltage drop across the ground return path.
CH D – Probe on Bat Positive Terminal

All probe ground references use the same batter negative clip to provide the exact same ground reference wire path for all channels.

Below is the wavefrom of my initial test, u can clearly see the weird drops and spikes, the RR DC output voltage drops towards 0V at the same time the ground resistance seems to jump up as, this also cuts the stator phase short.

Now the exact same probe setup above but this time with my own DC return path aka the described own positive and negative wire with a fuse directly to battery.

To note here is the ground resistance is much lower and also as this was a bit after the first test the battery has a higher voltage.

Now this waveform below is a reference i used as at some point i was thinking maybe this is just how the RR cuts off and its normal, as i dont have atm any similar bike to the engine type of the hyosung bike i could only do the exact same setup on a CBR600RR 2003 so below is the waveform for that and this does not have those massive drops of voltage and yes i know this is not a good comparison to hyosung engine type but it uses the same charge system with a shunt RR.

Also to note here is no matter how hot the RR was even when it was boiling hot like oem hyosung RR that broke it never stopped charging it always charged and never had that failure point i am experiencing on the hyosung where it just stops charging and either shorts out like the oem one or recovers after cooling off. It always worked at idle and high rpm.

Now also i also run the setup of test 1 until the failure event once, and got this waveform after it stopped charging.

To note on the post-failure waveform, after the R/R thermally fails and stops charging, the behavior is strange. It’s unlikely this R/R has any built-in thermal protection to shut down gracefully. If it had truly shut down completely, all SCRs would be fully fired and the stator phase on Channel A should show a flat line at ~1.5-2V just the forward voltage drop of two diodes routing current straight back to the stator. But that’s not what I see. Channel A still shows 14.4V rectangular waves as if the R/R is actively regulating at ~50% SCR duty. Yet the R/R DC positive output reads only 12.86V while the battery sits at 12.93V meaning the battery is actually at a higher voltage than the R/R output, so zero charging current can flow. The math doesn’t add up either: a 14.4V stator peak minus ~1.4V across two diode drops should yield around 13.0V at the DC output, not 12.86V. Something inside this R/R is clearly not functioning correctly after thermal failure it’s neither fully shutting down nor properly charging, it’s stuck in a broken state where it wastes stator energy through partial SCR firing while simultaneously failing to deliver any power to the battery.

As it seems like there is no option to enlarge the images i also added them in the same order to imgur: https://imgur.com/a/soi5HHP

[♠️ M77]

Hey,

if you disconnect the RR itself,  and do this:

– Rev the bike to 5,000 rpm maximum.
( I know the GV650 doesn’t have a Rev counter , so i assume you have a tach reader of some sort?)
(If not,  try idle voltage + 1/4 throttle + 2/4 throttle)     And Max throttle again (although hyosung does have a hard limit on their manuals for the AC output at 5K RPM mark, if it exceeds that , then further revs don’t matter as its replacement time)

– Connect the meter to 500V AC and probe any of the 2 pins of the 3phase yellow wires in any order and do it 3 times.
Eg. Pin 1 /Pin 2 = Voltage?
Pin 2 / Pin 3 = Voltage?
Pin 1 / Pin = Voltage?

Then let it cool down for least 12 hours outside in a shade (away from any sun heat radiation) , or overnight is best.

Get the meter out again switch to 10 OHMS  (Ten) and probe those 3 pins again.  And report what each combination says 3x

Resistance is the pretext to fry electronics (slow cooking) therefore the harness weakens.  Hyosung has used thinner gauge wires on the EFi models compared to carb models.    And also any oxidization of the pins , increases the resistance of the plugs connecting the stator to RR to harness.

Furthermore,  is the stator OEM or  aftermarket ? and I assume it is still using DAEWOO ECU?   (We got Delphi in 2012 here in UK but also Daewoo units phased out by 2014) – It is the Daewoo Electronics that have plagued the 650 models and 250cc models but fortunately we can fix certain aspects of it.

Normally I put an extra red wire from the RR to the battery with a 10A fuse.   I’d rather a 10A fuse blows up so i know it won’t cook the battery next and the RR is also still connected to the main harness which either uses  a 20A relay box or 15A fuse or 20-30A fuses  (Hyosung made variations of EFi harness over the years, so small things change)

Before I digress further,  I will await the report of the stator information, it is best we start there.  The RR can’t do anything until the stator feeds it.

i will assume you’re not using a Lithium battery  (if so, I would advise against it due to the variable voltage nature of the Hyosung charging system which Hyosung manuals state it can tolerate up to 15V but 13.5V minimum DC to start charging the bike)

Keep in mind, if the fuel pump is OEM and suspicious or some aftermarket version,  it may contribute to the additional charging system taxation which the RR will just get hot.  Daewoo pumps are specific  as they run different pressure ratings compared to later Delphi units.   Daewoo pumps are Black with OEM numbers printed on it   (the Aliexpress clones are black/blue intended to run the Delphi systems – Daewoo stopped making their pumps as they went out of business.   So fi you find another used Daewoo pump , look after it.

I can’t remember if it is 3.5BAR or 3.0 bar but it is possible to manually check the pressure yourself.

Something else came to my mind but worth thinking about, in the context of the charging system, this “extra” resistance (aforementioned above^) does not necessarily mean the regulator will “cook” due to higher current; rather, it indicates a failure in the efficiency and thermal integrity of the stator itself. henceforward we must address the stator first.     The general consensus amongst 70% of Hyo 650 owners who keep their bikes longer than 5 years  (not the stupid 1 summer riders who switch bikes after abusing it with cheap china RR’s and fitting lithium batteries or crashing them because they are too throttle happy on the streets as  their race track are ones you should not seek advice from)  is to make sure the Stator is in good spec all the way through ,  connectors are not oxidized (common for brown burns to to happen there) and fit MOSFET RR’s   but beware there is a LOT of fake mosfet RRs and even the fakes are now becoming almost hard to detect , real Shingdens (mosfet kings) are very expensive brand new.     A used one from a local bike you can see running with your own eyes is better salvage but still costly.      OEM RR’s have always let me down as Hyosung doesn’t make them , so its an outsourced product.

Also where i mentioned checking OHMS of the stator cold (about same temps you would check valve clearances)  , this springs to mind , If one phase is example 3OHMS and others are different like 2OHMS    (Pin 1+2 = 3Ohms ,  Pin2+3=2Ohms , Pin1+3=2Ohms), the RR must handle an unbalanced load. the OEM RR uses either SHUNT or older diode tech (depends what Hyosung gets as they have many variations of their RR’s being made, it’s hard to keep up) , which dumps excess current “somewhere” to regulate voltage. That kind of imbalance could cause uneven heating of the SCR, or diodes within the regulator, leading to premature failure as you said that as soon as you run the bike , it is not long before it’s “cooked?” .    Just my random suspicions but please investigate and correct me if i am wrong as i am hoping we don’t have bigger issues on the bike and it could just be something small that was overlooked!

[Zargoo]

Hey, thank you for the nice and detailed answer, so it took me some days but I was testing and this is my progress so far with the help of your recommendations.

At first I measured the phases like you suggested, which I did many times over the course of searching for the issue, and they always measured fine at around 0.26-0.28 at cold after sitting overnight and right after 5k rpm.

Now the stator basically always measured fine in terms of ohms. Now what I found is I hooked up the oscilloscope again and measured the phases phase to phase again, aka Pin 1-2, 2-3, 3-1 again, and also used the pick-up signal to get an RPM reading. And at 5k rpm I had 28V – 30V – 18V, which is very uneven; the drop to 18V is quite suspicious. So it seems it was like you said, an unbalanced load.

So with that info, I ordered a new stator and also a genuine Shindengen FH022AA.

Now after swapping the stator and the RR and also making an adapter with a 10A fuse, the problem was that the fuse always blew. At ignition on it was fine; at crank it blew. I then used a current clamp to test the amps on start and it was 15A, so I swapped to a 15A fuse and it now worked. Now from testing, the headlight takes 5A, the fuel pump at idle also 5A, and the RR seems to charge at 15A, and measuring at the battery positive wire, it receives 5A of charging current at 13V (the battery was a bit discharged already and was only at 12V).

Also, the main fuse on the bike is 30A, and yes it uses a Daewoo ECU, and it also still has the original Daewoo pump. And also yes, it is not using a Lithium battery; it’s a YTX14-BS gel battery.

Now at idle everything now seems fine; it no longer overheats the RR after 30 seconds of idle. Also, I tested with an external battery, connected the RR directly to a fully separate battery, and it charged at a better rate of 14V than what I saw on the bike at idle.

Though now I have quite a different problem that might be worse or better, not sure yet. Because the following is happening now: at idle the bike runs and seems to be able to run until there is no fuel. But when I rev the bike to 5k rpm, something weird now started happening. The first few times it is fine; the charging current goes up to 14V at high rpm then drops again. Stator phase to phase is around 35V – 40V; at idle it’s at 30V.

Now I am yet uncertain what the exact cause is, as I did not yet start to investigate, but it yet seems to happen randomly. I rev the bike, I can see battery voltage drop to 10,62V at high rpm with 12-15 amps pulling on the battery. Then after the revs and load, it goes back to 5A and 11V, which is way too low, and then the bike runs for 10-20 seconds and dies.

Now I did not yet test anything and will start probably tomorrow, but that is my first observation for now and might be wrong. I checked the RR 15A fuse and it was fine. One of my suspects is the ground strap from the battery negative, as this might cause high resistance under load and drop the voltage. Also, it could be the battery, as even if it did test on my tester at a low impedance of 12.62 mOhm, it could still be faulty. Also to note, I did connect the RR directly to the battery, not using the harness, and the same thing happens.

Also to note is that when I first got this bike, it was not starting at all and the issue was a cooked wire. I was testing each ECU wire and noticed some mismatches with the wiring diagram and then after opening the harness found 3-4 wires melted together. After fixing those, it ran, and I then had all the issues with the charging system. Now at least with the new stator and RR it seems fine, but still something might be off.

Also interesting is the tachometer, as it has an FI lamp which from reading the manual should turn on when there are issues with the FI system. From the manual:

“The injection signal is stopped, when the pick-up coil signal, roll over switch signal, NO.1 & NO.2 ignition signals,
NO.1 & NO.2 injector signals, fuel pump relay signal or ignition switch signal is not sent to the ECU.
In this case, “FI” letters is indicated in the LCD panel ① continuously. Motorcycle does not run.”

So I once disconnected the pick-up signal, but the FI lamp never turned on. Back then, I just thought it might be a defective lamp or tachometer, or it just needs the issue to happen while running for it to be memorized on the next start. (This was at the time when the bike did not turn on at all.)

Now I also tried the dealer mode switch and it also never worked or showed anything on the tacho display.

Also, on the wiring diagram I saw there is a CAN TOOL connector, and it looks like a K-line connection to the ECU. I also tested this with my motorcycle diag tool but also could not get any readings on any K-line protocol. And as this is not a Delphi ECU, which I know for certain works with my diag tool from other bikes via K-line, I just ignored this as I thought this might just be a different own protocol on the Daewoo ECU, or simply the Daewoo ECU might not have a real diag at all.

Also, one more weird thing when I started testing is the radiator fan turns on, but the tacho shows the water temp at nearly the lowest; from like 10 steps it has, it was at 2. And from other bikes as reference, usually the fan turns on at at least 5 or more. And also, one weird thing is the km on the tacho, because the bike should have around 2000 km, but the tacho just shows the maxed-out number possible of 999999 km.

Because of that, I am now slowly starting to think maybe it’s also an ECU issue, though it’s a bit unlikely, or so I think, because the ECU itself gives power to the fuel pump and injectors and the bike does run fine. If there were any major issue with the running itself, then maybe, and to be honest, I’d rather just have wrong things in the tacho than the bike run poorly or not at all and requiring a new ECU.

But just wanted to provide a bit more context about the bike and how it started, as this might help with the current issue I am seeing where the bike dies with a very low battery voltage after some revs, even though at idle it seems to charge, and on an external battery it charges even better, it seems. As I am also uncertain if the 15A fuse on the RR is really correct, or if that is the issue already and it should be less than 10 but is on this bike for some reason 15.

But already, thank you for the big help, as this is my first Hyosung bike and I’m really hoping to get it running, and sadly I don’t have any other Hyosung bike I could reference, as just having a second running GV650 FI would immensely speed up the diag.

[♠️ M77]

Hey,

Sorry if this reply was too short but this came to my mind,  as i was dealing with this a few days ago!

We got a GV EFi that stopped charging and we found the connectors melted , despite being a new stator! – However, it turns out the stator didn’t match the flywheel for whatever reason.

So to test it, we got a 337 code (no signal from pick up coil) ,  fine… We swapped it again with another stator ,   the bike ran,    and the connector was replaced.

This was a 3 phase plug,  so while the bike was running for 5 mins, the various Mosfet RRs we have on the shelf were all saying 14V , we put an inline fuse on the battery RR wires to be safe.

I kid you not, the Stator’s 3 phase wire was getting hottter and hotter to the point where , I wonder to myself , perharps the stator simply is internally shorting itself or it’s on the wrong flywheel  (hence on certain models Hyosung sells stators with flywheels together)   or  the wires were too thin ,  mind you the connector is new and has nice brass colour pins , it was getting too hot.

I have not solved this yet as the bike was being stripped down in to a carb conversion instead  (less electronics to worry about later for the new owner!)

This was a Delphi 2012  (the very early one) , so it still had some old daewoo electronics and ran fine on its black fuel pump.

Check your bike for:

• Wires getting warm ?
• Headlight wires getting too warm ?
• Smell the plugs for any signs of burns?
• Check the Fuel Pump Relay & Other Relays = If they start going funny, they will start taxing the stator back.

Just some ideas to try if i had not already mentioned

 

Your ODOMETER will probably stay that way as sadly i went through it myself, the old OEM RR briefly overspiked the whole harness, so it made things go a little haywire , except my ODO went to O miles , had to start over again (where it said 10,000 miles before) , likely ruined a battery or a capacitor inside the ODO board but i did not check at the time as the rest of the clocks where fine for the rest of the bike’s life.

 

Though 25-35V AC at 5K rpm isn’t good , it should be least 60V on each phase as per OEM ?

Though not possible to acquire anymore but the special tool used to read the ECU is Hyosung specific and they only ever gave it to dealers for warranty claims , so i was not fortunate to get one   (I came on the Hyosung scene in 2015 circa , so Hyosung had already moved on to Delphi Electronics!)  , hence you were not able to properly read the  K-Lines of the dealer plug.    We simply rely on the flashing sequences of the Fi light.

Daewoo as i know it , will flash red , while alternating 0 , Fi , 0 , Fi on the dash = Fuel system woes or ECU gone haywire.

If you don’t get error codes while it is running, that should be a good thing I hope

Delphi as i am on now, will stay red until i press start, once the bike fully starts, the red light goes away.   It will flash briefly during a ride if there is issues with it.

If you read the service manual , make sure its an 09-11 as   from 2013 onwards is Delphi , so error codes in newer models will be confusing where it doesnt apply to an older ECU.

[Zargoo]

Hey,

Thanks for the detailed reply, was working on it yesterday again, and checked the stator again and it was at 5krpm 80VAC so that was fine, the 35 I mentioned earlier were while everything was connected and the bike charged.

Now to quickly find what could cause the bike turning off, as I assumed this is an electrical fault (something pulling too much amps), I started to disconnect everything, and the weird thing now is when the bike is cold and is started it will work until it’s warm.

Now when it gets warm after some time it starts to drown, I would say hard to describe, but it’s as if there is no spark for one cycle and then runs fine again and then drowns again and so on, and also pops can be heard from the exhaust, so I am pretty certain I now have to look and check the coils, injectors, and spark plugs. If those are fine, it might be an issue with the ECU, as the speedo already was hit by the shorted wires that the bike had when I first got it, aka the random km value.

Also checked again which wires were melted together, as I before fixing it wrote it down, and it was the Red power wire to the ECU with some others, so it might be likely that the ECU also took some damage because no matter what sensors I disconnect while the bike is running and dealer mode is enabled, I never get the FI lamp to turn on.

As after testing some more, I got the bike to die suddenly while nearly everything was disconnected. I disconnected all lamps and even the speedo, monitored the RR amps output and voltage, and it was 14V at 5-7 amps, aka only the fuel pump really running, and the bike just died.

Also, what is weird is it could be an ECU fault, but it does not really align with the fact that it works when cold, but after running for 5-10 mins and getting warm it starts that weird drowning. Also, it is not regular; it’s like it gets no spark for 1 cycle, runs fine for the next 30 seconds, then gets no spark for 2-3 cycles, runs fine again, then for 1 cycle, and so on. And then after it runs for multiple minutes it suddenly dies as if it skipped 5-10 cycles at once.

Maybe you know what this could be.

Also, do you know by any chance what the usual amp usage is on the GV650? Because no matter what I do, a 10 amp fuse on the RR won’t work, as when I measured just the headlight + fuel pump it’s 10A, + blinkers, brake light, radiator fan, it easily gets to 15A, and then when under high RPM it even goes up to 19 amps. The Shindengen RR says it will work at 30A steady, but not sure if the GV650 should be using 20 amps. As I then used a 15A fuse, which under high RPM and high load, aka everything on, also burned. Now I’m on a 20A fuse but not sure what the GV650 usually needs, as I saw upgrade kits that used 10 amp fuses.

Also checked plugs, wires, and relays, and they seem fine, but will probably swap all relays as they could be the cause for the high amp usage, as I did not yet do a voltage drop test on those relays. What I found weird is the installed relays are all 20 amps, but when I checked the parts catalogue and service manual it says those should be 30 amps. And from my measured amps at high RPM, which was at 19 amps, those relays would have worked basically at the limit of their rated amps.

And yeah made sure the service and owner manuals i was using are 2009.

[♠️ M77]

Good discoveries there!

As far as i know on my side , all the GVs i ever touched being Fi models , they used a 30A fuse for the fuel pump side, its own fuse box i should say, the 2nd fuse box will be 15A for general electronics , the lights took 20A relays , and there is also a mixture of 20A and 30A relays in the battery rack.

I don’t know if you have a minor harness revision for your market,  can you confirm how many relays the bike is using and how many fuse boxes are there , they should match the UK daewoo ones I lay hands on.

The black pump is very thirsty , it draws a lot but it is a given since it’s constantly running.

Heat is the enemy => Check if possible the values of the water temperature sensors in the thermostat and radiator fan switch ,  and other temperature sensor on the bike.    Now i did get an error from the ECU where it ran cold fine, but it was rough , the Fi flashed a sequence telling me to replace the engine sensor that checks cylinder temp.

Another heat problem i faced with a different GV was that it actually shut down mid-ride and had to wait for it to cool down, it was the stator’s pickup coil gone haywire and the engine was popping a lot.

If you unplugged everything except the pump to keep the bike running , I would check:

• Temperature related sensors / Lambda Sensor
• Fan Switch  (unless the radiator is ice cold for 15 minutes and the fan hasn’t come on yet?)
• These sensors tend to send OHM readings back to to the ECU, so if the value is off , the ECU just cuts off the fuel pump supply., then the bike dies.

You mentioned that sometimes you hear the cylinders dropping in and out?

• Would the primary and secondary resistances of the coils be affected too drastically ?  Ie.  (the coil without the CAP attached would say 15K Ohms  but after 15mins, it jumps to 40K ohms hot ?)   OHMS will go up and down based on temperature which is normal but not too much as there is a range of values accepted by the service manual.
• Get NGK Caps if possible (if you have already , check their resistance without the coil attached) , we don’t know if they waned,  then the sparks drop when it gets hot , as it gets pretty hot inside those engine heads where the plug caps go to. So hence we really don’t trust the OEM caps (the black ones) they are the first things to go.
  If not,  try SV1000 caps (should be OEM ones) and yes it is a good call to check your plugs and the coils themselves.

I could not give you a true figure of what amperage every item uses on the GV650 , as Hyosung changed many parts over the years  (Carb,  Mitsubishi EFi (rare), Daewoo, Delphi , along with harness revisions  sometimes for the same ECU.  My delphi uses 20A relays where the Daewoo used a mixture of 30A and 20A, but i would change all the relays and see if the power draw has improved ?

I would really hope the ECU is OK,  but be ready to hunt hard for a spare one  (practically scour the earth for it)  or get a Delphi Harness and Delphi ECU as plan B if we cant replace the ECU , however a crashed GV650 will be a good donor for testing also before messing too much with your live one, so keep an eye or just as a back up.

ECU could possibly die due to heat  (I can’t confirm if it has an internal temp sensor like a PC CPU does where if it reaches a TJMAX it shuts down to avoid as fire but , i believe this daewoo ECU is a little more primitive than the Delphi ECU, so i can’t assume 100% correct on my assumptions here , or otherwise , we could suspect a small piece of circuitry inside the ECU is now more heat sensitive since it was spiked before but i hope not,   otherwise a dead daewoo ECU just wont even entertain the pump to prime before starting.

For your RR,  if it gives off 14V but blows a 15A fuse, that’s crazy , we might have a problem of resistance , i only ever experienced a blown fuse from the excessive draw from the fuel pump waning or the stator was waning  (hence on my previous reply in regards to heat on the connectors)

I have a theory ,  what if we source a battery pack 12V a good one that’s not going to harm the motorcycle ,  disconnect the stator, disconnect the RR , let the bike run purely of the battery pack  but do add an inline fuse to be safe and see if it dies out ?  –   You could measure how much juice it is drawing from the battery and how rapidly does it deplete the battery , you could use another spare good bike battery for this too.   It is a theory for you!

[Zargoo]

Hey,

So it took me some time, but it seems to have been the ignition coil or plug. I measured both in cold and hot, and they always measured fine for some reason, within the specs. But I connected my oscilloscope to the ignition coil’s ECU signal and pick-up signal and R/R amps output, and after that I could see quite clearly that at the exact moment one of the coils fired, the amps dropped to 0, meaning one of the coils was shorting and required more amps than the R/R supplied, which dropped the whole system to 0 amps. This also caused the headlight to flicker for that moment. Now I got NGK plugs, Tourmax IGN 303 (the ones on that Suzuki you mentioned) ignition coils, and NGK spark plugs, and now the problem seems to have been fixed. I ran the bike for over 30 minutes at idle, and it did not die, which was until now the longest time it ever ran.

So for now that is good, but one thing that bothers me a bit is the FI lamp and dealer mode, as both don’t seem to do anything. I disconnected the intake air pressure sensor and temp sensor, and in the manual it says it should show an error via code in dealer mode or blinking of the FI lamp, but the lamp never lights up. Also, on bike start it never turns on. I also checked the PCB itself, injected 3.3V to the FI lamp, and it worked, so the LED on the PCB of the speedo seems to still work.

Also, one other thing I am unsure about is the fuse on the R/R, as the bike’s main fuse is 30 amps. After doing a test and turning everything on that is possible, I got at high RPM to a usage of 20-22 amps, so for now I swapped the 20-amp fuse at the R/R to 25 amps to be sure. Theoretically, the Shindengen should be fine with 30 amps steady, but I would rather like to have a bit of a safe buffer. But as you said, the 15-amp fuse on the R/R should work, so I’m not sure what is going on and if that is normal, as it seems like the usage is steady now, just that it’s steady at 20 amps.

But for now it seems okay. I will do the normal service parts for now, like oil and air filter, and will see after a test drive if maybe I get some errors or the FI lamp to work.

Maybe you have some recommendations from your experience with the GV650, if that 20 amps makes sense on the R/R, or if it could still be worth checking for issues with the harness. I did check most of the wires and voltage drops and found only one big drop on the headlight fuse holder, which I replaced, and now it is near 0V of voltage drop instead of like 0.3V.

Also, big thank you for all the help and recommendations.

[♠️ M77]

This is fantastic news! – Who could have thought ? but you could see why 99% of Hyosung owners go strictly NGK caps immediately as the factory caps were made by a company called “Golden” in china,  they always caused random issues there and there, so it wasn’t worth the anxiety.  Nice move on the coils too,  Tourmax is OK,  japanese parts, it should mate well with the RR.

For now, leave her at 25amps as as safe buffer. Service the bike , and take it for a short spin not too far from home and come back.      While the bike is still hot,  measure any resistance of the new parts and other sensors, to see if they are within the safe margins ?   If  yes,  then we should assume to go for another longer ride and see how it actually feels  (power , throttle ,  idling at traffic,  fan temps  (if the fan spins etc) )  now you get some real world data for yourself to make a better judgement.

If you feel anxious, carry a spare jump pack to start the bike and limp slowly back home but heaven forbid , as you said it’s idled for 30mins without a hitch.

Another thing,  find out if the amperage changes when the 55w headlight is ON  or OFF  ,  and watch for any RR wires getting hot.

I have no correct answer yet in regards to the Fi light , despite the bulb working when manually triggered , i must assume it being OFF is a good thing ,  find out during your longer rides if it ever blinks whatsoever ?

If you come back and say there is zero issues during the test runs , then you must be ready to go! (Hopefully)

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