Hyosung GT 650 i: No / stuttering acceleration

[NoName1]

Hello everyone,

For 4 month I am a proud owner of a Hyosung GT 650 I (build 2013). Last weekend it took it on a ride. Everything was fine but then I pulled the throttle really hard. The bike started to accelerate but suddenly the acceleration was gone completely. A few hundred meter further the FI light turned on. I was able to ride the bike back home but now the bike stutters when I accelerate. I also think I noticed some more misfires. Unfortunately, I don’t have much knowledge of motorcycles or cars but I have someone how can help me (mechatronic at BMW). I already tried to read the error code by bridging the pins under the sozius seat, but it tells me “no err” where the clock is.

I hope it is understandable what I mean by “stuttering acceleration”. Does anyone have some tips or advices how to get the bike to work again? I am really desperate as I only own this bike for such a short time. I also don’t have a workshop near that repairs Hyosung bikes.

Kind regards

Jan

[Simon]

This might seem a bit simple but disconnect all the sensor, coil connectors clean them & try that, if no error codes are shown then it could well be a dry connection, hyosungs are a bit cheap in their electrical department it’s a shame because they are good bikes.

[Peadar]

This sounds awfully like one of the throttle cables has snapped. Check both bodies are moving when you twist the throttle. It would throw a F1 fault. If it’s cable it likely won’t  rev above 4000 in neutral.

[NoName1]

Hi Simon, hi Peadar,

first of all sorry for my late reply – I was on vacation.

@Simon: I tried what you suggested (was pretty difficult for me as motorcycle newbie) but unfortunately it did not help.

@ Peadar: What do you mean by “bodies”? Do you have a picture maybe? I will try if I can get the over 4000 later that evening.

Still happy for any other suggestions 😊

[Peadar]

Hi Jan. If you look at what moves on the engine when you twist the throttle where the cable is attached should rotate on both sides of the engine. If both move then cable is ok. If only one side moves then cable is most likely snapped. You described twisting throttle hard and if cable was badly adjusted then it can fail.

[NoName1]

Hi Peadar,
so I double checked what you wrote and both sides of the engine are moving.
But you were right with the rpm. It seems like the engine stucks at 4000 needs a lot of force to exceed over this mark and than raises its rpm a lot faster than normal. Hopefully it is understandable what I mean. Also the missfires beginn after 4000 rpm.

[NoName1]

Does no one have any other ideas? Getting really desperate not beeing able to ride that bike  😥

[Peadar]

Hi Jan.

2 things to check.

1: Throttle position sensor. I’m not familiar with the system for GT650i so you would need to Google it.

2: Throttle body butterflies. To check that both are operating properly you have to remove the tank and airbox and see if the butterfly valves are moving the same amount. This may sound confusing but once you have the airbox off it should become clear. If one is not opening and closing freely then check for damage or carbon build-up.

Afraid I don’t have any other suggestions so I hope this helps.

 

[NoName1]

Hi Peadar,

thanks again for you answer 🙂

1. I found this really helpful video which shows how to adjust the tps at exactly my bike: https://www.youtube.com/watch?v=oYJJLE0ZFDI  I will give it a try later.

2. Okay… all new words for me 😀 But after a bit of using Google I guess I know what you mean now. Next weekend a friend of mine is coming over and we will check the throttle body butterflies.

Are those defects that can happen in the situation I described in my first post? As my bike already had some issues with electronics I thought it might be something like this. 2 month ago a cable burned so we changed some parts and the bike was running fine again. I dont know the english terms for those parts but it was Nr. 2 from here and nr. 5 from  here

[NoName1]

Solution for me:
There was a cable behind the battery (pretty easy to reach it was sitting there directly) with a lot of tape around it. It seemed that the owner before me renewed the connection between these cables and this new connection became lose over the time. We renewed it again and since then it was fine. Unfortunately I dont own this bike anymore so I cannot take any pictures.

[Author]

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