2012 GT650 de-restrict
Looking to de-restrict a 2012 GT560 EFI model, have heard that an ECU remap is needed after the bracket has been removed from throttle body. Is this needed or is the mechanical mod enough?
Cheers
Topic Tag
gt650
Oil change, front fork
Hyosung GT650 Comet-06
Hi there.
With empty tubes, front fork manual tells:
“Oil level 146mm (5.8 in) from end of outer tube
(when maximum compressed without spring)”
or/and 380 cc.
The recommended level is obtained with 380 + 60 cc at each leg.
Anyone who can explain ‘wass’up’?
The hight of inner thread, from top to ‘top of outer tube’ (oilfilled) is 25 mm. So measure top(top) 😋 to oil is 171 mm.
[How to Tutorial] [Bike Mod] 650/250/125 – AiS Block Off Removal (EGR Delete)
Hyosung AIS Removal Guide: EGR Delete for GT650, GT250 & GV125
⚠ WARNING: This technical guide involves modifying the Air Injection System (AIS). Proceed at your own risk. Incorrect installation can affect engine longevity or emissions compliance. Ensure you have the correct tools before starting.
If you are looking to improve the exhaust note and throttle response of your Hyosung GT650R, GT250, or GV125 Aquila, performing an AIS (Air Injection System) block-off—often referred to by riders as an EGR Delete—is one of the most effective “free” mods available. This process is common among race teams and enthusiasts looking to strip away parasitic emissions equipment.
What is the AIS (Air Injection System)?
The AIS is designed to help motorcycles meet strict Euro emissions standards by injecting fresh air into the exhaust port. This helps burn off unburnt fuel in the header pipes. While great for the environment on paper, it often causes excessive “popping” on deceleration and adds unnecessary clutter to the engine bay. It essentially “fakes” cleaner emissions by diluting exhaust gases, acting like a parasite that steals potential engine efficiency.
Benefits of the AIS Block-Off Mod
- Reduced Exhaust Popping: Eliminates the loud, annoying backfiring often heard with aftermarket stainless steel exhausts.
- Improved Induction Roar: Gives the bike a deeper, more natural groan at idle and under load.
- Smoother Mid-Range: Many riders report a noticeable improvement in the 4,000–7,000 RPM range, particularly on smaller 125cc and 250cc models.
- Simplified Maintenance: Clears up space around the cylinder heads, making spark plug changes and valve clearances easier.
Whether you are running a stock setup or a full custom exhaust system, removing the AIS is the first step toward a true performance tune. Full credit goes to the original community author who compiled this technical manual.
Ready to start the mod? Download the step-by-step technical book below:
Community Note: This mod is highly recommended if you have recently upgraded to a Delkevic or similar aftermarket silencer.
[Tutorial] Hyosung GV650 & GT650: Tip Over Sensor (TOS) Bypass Mod & C23 Fix
Fixing the C23 Error: GT650 & GV650 TOS Modification
If your Hyosung GT650 or GV650 is showing a persistent “FI” error on the dash and refusing to prime the fuel pump, you may be dealing with a faulty Tip Over Sensor (TOS). When this sensor fails, the ECU assumes the bike has crashed and cuts the ignition for safety. This guide explains how to bypass the sensor using simple resistors to get your V-Twin back on the road.
🔧 Diagnostic & Modification Info
The TOS is designed to kill the engine if the bike tilts past a specific angle. Over time, the internal float can stick or the circuit can fail, triggering the Dealer Mode Error Code C23. A new sensor can cost upwards of £80–£100, but a bypass can be made for pence.
- Fault Code: C23 (Tip Over Sensor Malfunction).
- The Symptoms: “FI” on dash, fuel pump won’t prime, engine dies after 2 seconds.
- The Fix: Replacing the internal sensor circuit with two specific resistors to “trick” the ECU into seeing a safe upright position.
- ⚠️ Warning: This mod disables the automatic engine kill-switch during a crash. Perform at your own risk.
Credits: We owe a massive thanks to the original author for documenting this electronics bypass. This PDF is a permanent mirror hosted by HyoRiders. If you’ve successfully cleared your C23 error using this method, please leave a comment to help others!
[DOWNLOAD] Service Manuals & Owners Books – Hyosung GV650 & GT650 (Carb & EFi)
Hyosung 650cc V-Twin Master Resource
Welcome to the complete documentation archive for the Hyosung GT650 (Comet/R/S) and GV650 (Aquila/Avitar). These 650cc machines are the powerhouses of the Hyosung range, featuring the iconic 90° V-Twin DOHC engine. Whether you are synchronising carburettors or diagnosing a Delphi/Denso EFI system, these permanent direct links provide the official data you need.
650 Series Generation Guide
Identifying your specific 650 model is critical for correct electrical and fueling maintenance. The GT and GV series evolved through several major technical phases:
- Carburetted (2004–2008): Features dual Mikuni carburettors and the classic “silver” engine finish.
- Gen 1 EFI (2008–2011): Transition to Fuel Injection. Uses the “S&T” or “Mitsubishi” marked systems with a green LCD dashboard on GT models.
- Gen 2 EFI (2012–2018): Features a major visual facelift (RC for Sports, P for Naked) and the upgraded Denso/Delphi ECU systems.
- 2024+ GV650 ABS: The latest revival (GV650PJ/PC) featuring full LED electronics and ABS. (Manuals pending; see specs link below).
Technical Note: The 650 engine produces approx 79hp (Carby) to 74hp (EFI) and requires 10W40 semi-synthetic oil (~3.0L with filter). For 2024+ models, visit our GV650 ABS Wiki & Specs Page.
🛠 WORKSHOP SERVICE MANUALS
📕 OWNERS HANDBOOKS
Safety Notice: Ensure you are using the manual that matches your ECU type (Mitsubishi, Delphi, or Denso) to avoid electrical damage. If you have documentation for the 2024+ GV650 ABS models, please contribute by commenting below. All links are permanent mirrors hosted on the HyoRiders servers.