GV650 EFI idle issues

[Chopper_Whitewolf]

I have tried adjusting the TPS but I still have low speed lag and stutter after getting the engine up to temp. The issue is most notable when coming to a complete stop after exiting the motorway or when stuck sitting in traffic. While sitting still after the bike is up to operating temperature, the idle will be so low it is not uncommon for the engine to cut out. Each time I have adjusted the Throttle Position Sensor it runs a bit better for a day or so then the issue returns.
This is my first electronic fuel injected bike. I have decades of experience with carbs but am at a complete loss with these electronics. I’ve been pondering sending my ECM off for a flash tune.

Please advise

[♠️ M77]

Is halfords near you?  Get a bottle called WYNNS FORMULA GOLD PETROL  ,  strictly this bottle only as i rave about it all the time. Redex is just junk.
Pour the whole bottle inside.
Make sure there is about max half a tank inside  (less diluted if the tank is full) , ride until you reach 1 or 2 bars as long as you are within proximity of the service station to refil.

Use e5 fuel only.  They don’t like E10 at all.

Use fresh CR8E spark plugs from halfords during this.

Report back and let us know if the “soft cleaning” has helped your entire fuel system  (incase there is debris all over the fuel system from tank pump right down to injectors)   , yes a pump that’s bad will make a bike run very rough , vise versa to the clogged injectors too.

If not,   are you able to download the service manual on this forum that corresponds to the year of your bike, and follow the instructions to trick the ECU to output any error codes  (past or present that may be stored in the ECU)

Externally,  remove the “GOLF BALL” that is near the airbox system with 3 or 4 pipes sticking out of it going from airbox to the throttle bodies , this is your “Idle Speed Controller Valve” (ISCV) , it is what controls idling when the bike is at closed throttle  (neutral) ,  sometimes this object needs replacing.  There is a few versions ,  so take pictures ,  i may have spare ones on ebay of these ISCV’s

Check your regulator is 14v idling (13.5 absolute minimum) to 14.5v max and the voltage doesn’t drop when revving to about 5,000 rpm ish

If it does,  replace the regulator ,   unstable voltages will make the whole EFI system haywire , unlike carb bikes that can still chug on , but EFI likes the electrics delivered pretty consistently

Keep an eye on this topic too, it may relate to you a little bit i hope

GT650R Fuel Pump Fault

[Chopper_Whitewolf]

Excellent.
The chain conversion kit should arrive tomorrow or Tuesday. As soon as I’m able to get to Halfords I’ll start going down the prescribed list of fixes. Hopefully it is just a gunked up system from the previous owner having left it sitting for several years and the WYNNS FORMULA GOLD PETROL will set me to rights.

Thank you

[Chopper_Whitewolf]

These should hopefully arrive in the next couple of days too.
I’m a big guy and by myself, without any bags or pillion I’m 115kg. Unfortunately, I don’t have a garage but at least my flat has a private parking lot. Fingers crossed for good weather. Next, after recovering from recent expenditures, I’m going to get rid of that craptastic cheap can. Not only is it an ugly cheap knock-off not rated for 650cc, it doesn’t even have an adjustable baffle

[♠️ M77]

beautiful girl ,  really like the limited edition red frames & the cherry wheels,  don’t divorce it 🙂

as you have guessed , Scotland is a bit colder than Texas!  – So indeed, keep it as clean as you can, this island is wonderful for its green orgasmic sceneries but not the weather!

[Chopper_Whitewolf]

I’ve clearly got to get some mechanical issues sorted, but this winter I’d like to start addressing the frame rust and flaking paint. I’m also going to delete that unnecessary hunk of plastic attached underneath rear fender.
Do you happen to know where I might paint match for touch ups? I can’t seem to find the Hysoung paint codes for the 30th anniversary edition
(#86 of #1000. Yeah, bit of a brag)

[♠️ M77]

Chopper_Whitewolf wrote:

I’ve clearly got to get some mechanical issues sorted, but this winter I’d like to start addressing the frame rust and flaking paint. I’m also going to delete that unnecessary hunk of plastic attached underneath rear fender. Do you happen to know where I might paint match for touch ups? I can’t seem to find the Hysoung paint codes for the 30th anniversary edition (#86 of #1000. Yeah, bit of a brag)

Quote

Hyosung doesn’t usually say the exact codes as they use inhouse paint.   Maybe a local body shop can closely match it for you and mix in a spray can if you desire ?

[Chopper_Whitewolf]

https://www.manualslib.com/manual/406876/Hyosung-Gv650fi-Parts-Catalogue.html#manual

 

Found this, but haven’t yet been able to locate an OEM parts manual specifically for the anniversary edition. This site does seem to be a treasure trove for OEM manuals

 

[♠️ M77]

The codes in the books are used by dealers to tell Hyosung which panels to send if rider has a crash or needs replacing  ie.   For  Black rear panel,  we would say send us “12435HG12345-SBK”   =  SBK  Black code for some GT bikes.

On the Hyosung GT bikes, the red is different , and the closest car we found is Hyuindai Electric Red  (not 100% but almost there) , took years and 1 guy took a gamble to share with us all.

So i am not sure which Korean car would use the same paint as your frame.

Bodyshop was the way to do it.  They needed the bike with them to match paints (or try to)

[Andrew]

Hello. I have exactly the same problems that ‘Whitewolf’ describes in his initial post. Stuttering and cutting out in stop-start traffic when hot, which is sucking out all the fun. Only difference my GV650 is an older bike on carbs. Does that affect the advice given?

I have discovered through a video on YouTube how to easily extract the ethanol out of petrol. Would ethanol free petrol be a big improvement? BTW; you can also buy ethanol free petrol if you prefer, according to Harry Metcalf of ‘Harry’s Garage’ on YouTube.

Chopper Whitewolf: Why are you converting to a chain? I thought belts were more advanced and better all round??

Thanks

Andrew

[Chopper_Whitewolf]

I would prefer to stay with belt drive but the only belt I can get my hands on here in Scotland costs £300.00
I can get 520 O-ring chain anywhere and it’s way more affordable

 

[Andrew]

Fair enough. But have you solved the original issue with stalling at lights?

Still hoping for some advice on the stalling at lights issue. I have added some Liqui Moly Carb and valve cleaner (as mine is not an EFI). I added that, filled the tank with E5 and took it for a ride before taking the exhaust off, but there was no improvement after 20 miles.

Perhaps I should have mentioned that I bought my bike with an aftermarket exhaust fitted, but the original exhaust came with the bike. I asked a chap at the local Triumph dealer if an aftermarket exhaust could affect smooth running and he said it might, so I thought I’d return the factory exhaust to the bike. On removing the aftermarket one I found it had a great big crack at one of the joints (hidden from view) and the front cylinder fixing was loose because the gasket was missing. When a new gasket arrives I will be able to see if the factory exhaust improves it at all.

[Chopper_Whitewolf]

Ohhhhh boy!

Yeahhhh, any changes to intake or exhaust will change the behaviour of the bike.  Increasing the amount of air in (For instance via K&N high performance air filter) or the amount of air out, such as after market exhaust, will have some effect. Typically it will cause the bike to run a wee bit lean as it’s now breathing better.

For starters, there is an Idle Adjustment thumb screw. You can adjust this to set the default idle to run a bit richer. It will idle high til it warms up to operating temps, but that is the quick fix solution.
https://www.manualslib.com/manual/1018449/Hyosung-Aquil-Gv650.html?page=24#manual

Depending on the increase of airflow due to after market intake/exhaust you might need to change your carb needle jets

If you really want to get into the weeds of carby tuning I found a tutorial from Marcel

[Tutorial] How to adjust Carb Slide Needle (Tuning) – Hyosung GV & GT 125/250

Honestly, the aftermarket slip-on should not make that much difference. It might cause it to run a bit lean, just as a high performance air filter would do. The quick fix, once all your other issues are sorted, is simply making sure your spark plugs are properly gapped, your air filter is clean, and adjust your idle up to run a bit rich

[Chopper_Whitewolf]

Andrew wrote:

Fair enough. But have you solved the original issue with stalling at lights? Still hoping for some advice on the stalling at lights issue. I have added some Liqui Moly Carb and valve cleaner (as mine is not an EFI). I added that, filled the tank with E5 and took it for a ride before taking the exhaust off, but there was no improvement after 20 miles. Perhaps I should have mentioned that I bought my bike with an aftermarket exhaust fitted, but the original exhaust came with the bike. I asked a chap at the local Triumph dealer if an aftermarket exhaust could affect smooth running and he said it might, so I thought I’d return the factory exhaust to the bike. On removing the aftermarket one I found it had a great big crack at one of the joints (hidden from view) and the front cylinder fixing was loose because the gasket was missing. When a new gasket arrives I will be able to see if the factory exhaust improves it at all.

Quote

Does your carby GV have a manual choke?

[Andrew]

Yes, my bike has a manual choke. Now that I have fitted the original exhaust, and I have run it with E5 98 and Liqui Moly Card for a few miles it is behaving much better. It did still cut out on deceleration when getting down to 1st gear once or twice, but it will now idle when hot. I still get bang-and-pop on over-run, but with the new (original) exhaust it doesn’t sound nearly so bad. I did get a new air filter at the start of this year (along with the £600 service!) and comparing the colour of the old and the new it could have been the first new air filter for a very long time. It is now SORN for 6 months so I’ll start it up and idle it every month till Spring and then I’ll be sure to check the timing. I also got a brand new radiator for it from Aliexpress (item-1005005776337812) for £60 (bargain) as the old one had a very slight leak and I asked the servicing garage to add some ‘leak-stop’ (which I now see the manual forbids). So it should be breathing very well and keeping cool.

[Chopper_Whitewolf]

Running an aftermarket exhaust/ slip-on “can” or “silencer” really shouldn’t make a difference. Regardless, if you’re still running lean when up to operating temps it might be a good idea to pull the bowls on the carbs to check the floats aren’t sticking and there’s no bits or gunk in any of the ports/lines. Also, if the bike has set any lenght of time before, or after purchase, it might be helpful to purge the tank and fuel lines.

I’m glad you’ve got it rideable

P.S. The bang-and-pop is a thing some riders like and why they switch to aftermarket slip-on exhaust.

Best of luck

Cheers,
Chopper

 

[Author]

Posts

[Chopper_Whitewolf]

I have tried adjusting the TPS but I still have low speed lag and stutter after getting the engine up to temp. The issue is most notable when coming to a complete stop after exiting the motorway or when stuck sitting in traffic. While sitting still after the bike is up to operating temperature, the idle will be so low it is not uncommon for the engine to cut out. Each time I have adjusted the Throttle Position Sensor it runs a bit better for a day or so then the issue returns.
This is my first electronic fuel injected bike. I have decades of experience with carbs but am at a complete loss with these electronics. I’ve been pondering sending my ECM off for a flash tune.

Please advise

[♠️ M77]

Is halfords near you?  Get a bottle called WYNNS FORMULA GOLD PETROL  ,  strictly this bottle only as i rave about it all the time. Redex is just junk.
Pour the whole bottle inside.
Make sure there is about max half a tank inside  (less diluted if the tank is full) , ride until you reach 1 or 2 bars as long as you are within proximity of the service station to refil.

Use e5 fuel only.  They don’t like E10 at all.

Use fresh CR8E spark plugs from halfords during this.

Report back and let us know if the “soft cleaning” has helped your entire fuel system  (incase there is debris all over the fuel system from tank pump right down to injectors)   , yes a pump that’s bad will make a bike run very rough , vise versa to the clogged injectors too.

If not,   are you able to download the service manual on this forum that corresponds to the year of your bike, and follow the instructions to trick the ECU to output any error codes  (past or present that may be stored in the ECU)

Externally,  remove the “GOLF BALL” that is near the airbox system with 3 or 4 pipes sticking out of it going from airbox to the throttle bodies , this is your “Idle Speed Controller Valve” (ISCV) , it is what controls idling when the bike is at closed throttle  (neutral) ,  sometimes this object needs replacing.  There is a few versions ,  so take pictures ,  i may have spare ones on ebay of these ISCV’s

Check your regulator is 14v idling (13.5 absolute minimum) to 14.5v max and the voltage doesn’t drop when revving to about 5,000 rpm ish

If it does,  replace the regulator ,   unstable voltages will make the whole EFI system haywire , unlike carb bikes that can still chug on , but EFI likes the electrics delivered pretty consistently

Keep an eye on this topic too, it may relate to you a little bit i hope

GT650R Fuel Pump Fault

[Chopper_Whitewolf]

Excellent.
The chain conversion kit should arrive tomorrow or Tuesday. As soon as I’m able to get to Halfords I’ll start going down the prescribed list of fixes. Hopefully it is just a gunked up system from the previous owner having left it sitting for several years and the WYNNS FORMULA GOLD PETROL will set me to rights.

Thank you

[Chopper_Whitewolf]

These should hopefully arrive in the next couple of days too.
I’m a big guy and by myself, without any bags or pillion I’m 115kg. Unfortunately, I don’t have a garage but at least my flat has a private parking lot. Fingers crossed for good weather. Next, after recovering from recent expenditures, I’m going to get rid of that craptastic cheap can. Not only is it an ugly cheap knock-off not rated for 650cc, it doesn’t even have an adjustable baffle

[♠️ M77]

beautiful girl ,  really like the limited edition red frames & the cherry wheels,  don’t divorce it 🙂

as you have guessed , Scotland is a bit colder than Texas!  – So indeed, keep it as clean as you can, this island is wonderful for its green orgasmic sceneries but not the weather!

[Chopper_Whitewolf]

I’ve clearly got to get some mechanical issues sorted, but this winter I’d like to start addressing the frame rust and flaking paint. I’m also going to delete that unnecessary hunk of plastic attached underneath rear fender.
Do you happen to know where I might paint match for touch ups? I can’t seem to find the Hysoung paint codes for the 30th anniversary edition
(#86 of #1000. Yeah, bit of a brag)

[♠️ M77]

Chopper_Whitewolf wrote:

I’ve clearly got to get some mechanical issues sorted, but this winter I’d like to start addressing the frame rust and flaking paint. I’m also going to delete that unnecessary hunk of plastic attached underneath rear fender. Do you happen to know where I might paint match for touch ups? I can’t seem to find the Hysoung paint codes for the 30th anniversary edition (#86 of #1000. Yeah, bit of a brag)

Quote

Hyosung doesn’t usually say the exact codes as they use inhouse paint.   Maybe a local body shop can closely match it for you and mix in a spray can if you desire ?

[Chopper_Whitewolf]

https://www.manualslib.com/manual/406876/Hyosung-Gv650fi-Parts-Catalogue.html#manual

 

Found this, but haven’t yet been able to locate an OEM parts manual specifically for the anniversary edition. This site does seem to be a treasure trove for OEM manuals

 

[♠️ M77]

The codes in the books are used by dealers to tell Hyosung which panels to send if rider has a crash or needs replacing  ie.   For  Black rear panel,  we would say send us “12435HG12345-SBK”   =  SBK  Black code for some GT bikes.

On the Hyosung GT bikes, the red is different , and the closest car we found is Hyuindai Electric Red  (not 100% but almost there) , took years and 1 guy took a gamble to share with us all.

So i am not sure which Korean car would use the same paint as your frame.

Bodyshop was the way to do it.  They needed the bike with them to match paints (or try to)

[Andrew]

Hello. I have exactly the same problems that ‘Whitewolf’ describes in his initial post. Stuttering and cutting out in stop-start traffic when hot, which is sucking out all the fun. Only difference my GV650 is an older bike on carbs. Does that affect the advice given?

I have discovered through a video on YouTube how to easily extract the ethanol out of petrol. Would ethanol free petrol be a big improvement? BTW; you can also buy ethanol free petrol if you prefer, according to Harry Metcalf of ‘Harry’s Garage’ on YouTube.

Chopper Whitewolf: Why are you converting to a chain? I thought belts were more advanced and better all round??

Thanks

Andrew

[Chopper_Whitewolf]

I would prefer to stay with belt drive but the only belt I can get my hands on here in Scotland costs £300.00
I can get 520 O-ring chain anywhere and it’s way more affordable

 

[Andrew]

Fair enough. But have you solved the original issue with stalling at lights?

Still hoping for some advice on the stalling at lights issue. I have added some Liqui Moly Carb and valve cleaner (as mine is not an EFI). I added that, filled the tank with E5 and took it for a ride before taking the exhaust off, but there was no improvement after 20 miles.

Perhaps I should have mentioned that I bought my bike with an aftermarket exhaust fitted, but the original exhaust came with the bike. I asked a chap at the local Triumph dealer if an aftermarket exhaust could affect smooth running and he said it might, so I thought I’d return the factory exhaust to the bike. On removing the aftermarket one I found it had a great big crack at one of the joints (hidden from view) and the front cylinder fixing was loose because the gasket was missing. When a new gasket arrives I will be able to see if the factory exhaust improves it at all.

[Chopper_Whitewolf]

Ohhhhh boy!

Yeahhhh, any changes to intake or exhaust will change the behaviour of the bike.  Increasing the amount of air in (For instance via K&N high performance air filter) or the amount of air out, such as after market exhaust, will have some effect. Typically it will cause the bike to run a wee bit lean as it’s now breathing better.

For starters, there is an Idle Adjustment thumb screw. You can adjust this to set the default idle to run a bit richer. It will idle high til it warms up to operating temps, but that is the quick fix solution.
https://www.manualslib.com/manual/1018449/Hyosung-Aquil-Gv650.html?page=24#manual

Depending on the increase of airflow due to after market intake/exhaust you might need to change your carb needle jets

If you really want to get into the weeds of carby tuning I found a tutorial from Marcel

[Tutorial] How to adjust Carb Slide Needle (Tuning) – Hyosung GV & GT 125/250

Honestly, the aftermarket slip-on should not make that much difference. It might cause it to run a bit lean, just as a high performance air filter would do. The quick fix, once all your other issues are sorted, is simply making sure your spark plugs are properly gapped, your air filter is clean, and adjust your idle up to run a bit rich

[Chopper_Whitewolf]

Andrew wrote:

Fair enough. But have you solved the original issue with stalling at lights? Still hoping for some advice on the stalling at lights issue. I have added some Liqui Moly Carb and valve cleaner (as mine is not an EFI). I added that, filled the tank with E5 and took it for a ride before taking the exhaust off, but there was no improvement after 20 miles. Perhaps I should have mentioned that I bought my bike with an aftermarket exhaust fitted, but the original exhaust came with the bike. I asked a chap at the local Triumph dealer if an aftermarket exhaust could affect smooth running and he said it might, so I thought I’d return the factory exhaust to the bike. On removing the aftermarket one I found it had a great big crack at one of the joints (hidden from view) and the front cylinder fixing was loose because the gasket was missing. When a new gasket arrives I will be able to see if the factory exhaust improves it at all.

Quote

Does your carby GV have a manual choke?

[Andrew]

Yes, my bike has a manual choke. Now that I have fitted the original exhaust, and I have run it with E5 98 and Liqui Moly Card for a few miles it is behaving much better. It did still cut out on deceleration when getting down to 1st gear once or twice, but it will now idle when hot. I still get bang-and-pop on over-run, but with the new (original) exhaust it doesn’t sound nearly so bad. I did get a new air filter at the start of this year (along with the £600 service!) and comparing the colour of the old and the new it could have been the first new air filter for a very long time. It is now SORN for 6 months so I’ll start it up and idle it every month till Spring and then I’ll be sure to check the timing. I also got a brand new radiator for it from Aliexpress (item-1005005776337812) for £60 (bargain) as the old one had a very slight leak and I asked the servicing garage to add some ‘leak-stop’ (which I now see the manual forbids). So it should be breathing very well and keeping cool.

[Chopper_Whitewolf]

Running an aftermarket exhaust/ slip-on “can” or “silencer” really shouldn’t make a difference. Regardless, if you’re still running lean when up to operating temps it might be a good idea to pull the bowls on the carbs to check the floats aren’t sticking and there’s no bits or gunk in any of the ports/lines. Also, if the bike has set any lenght of time before, or after purchase, it might be helpful to purge the tank and fuel lines.

I’m glad you’ve got it rideable

P.S. The bang-and-pop is a thing some riders like and why they switch to aftermarket slip-on exhaust.

Best of luck

Cheers,
Chopper

 

[Author]

Posts