Front Brake Master Cylinder – Hyosung GT125 GT125R GT250R GT250
Upgrade your handlebar hydraulics with Korean engineering. Sourced directly from South Korea, this premium aftermarket unit replaces discontinued stock components with a robust, hard-biting piston setup. We run these on our own workshop customer’s bikes, ensuring reliable hydraulic line pressure for total stopping confidence.
✔ AFTERMARKET // MADE IN SOUTH KOREA
Fitment Note: Fits all Naked GT models (2003-2020) and GTR models with updated “RC” 2012-2020 fairings featuring the distinct diamond-shaped headlight structure.
| GTR 2012-2020 ✔ Compatible |
GTR 2005-2011 ❌ NOT Compatible |
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📸 PROVEN ON OUR BUILDS (GV AQUILA CUSTOM):
- South Korean Build // Precision manufactured replacement layout for true hardware reliability.
- Dual-Disc Ready // High fluid capacity provides massive stopping headroom for all 125cc and 250cc platforms.
- 2x Larger Bore // Increased internal displacement eliminates lever mushiness for instant hydraulic bite.
Description
Since the factory-original GT125 and GT250 handlebar cylinders were taken out of production, finding reliable pressure parts can be difficult. This Korean-built aftermarket assembly acts as a major mechanical upgrade, displacing fluid smoothly to ensure a wider safety margin than your standard lightweight setup demands. It serves as a direct, long-lasting replacement built to maintain consistent line expansion control.
💎 Technical Performance Spec
| South Korean ProductionEngineered with precision internal seals that resist long-term fluid breakdown. | Responsive Fluid PistonDisplaces volume rapidly to eliminate lever creep during firm stops. |
| Universal Bar MountingStandard clamp structure fits factory 22mm handlebars and clip-ons. | Integrated Fluid Sight GlassClear viewport window allows for simple, instant brake fluid level checks. |
📜 Model Fitment Guide
Confirmed Chassis Matches: Fits Naked GT125 and GT250 models built from 2003 to 2020. Also fits faired GT125R and GT250R sport units, but strictly limited to the updated “RC” fairing revisions built between 2012 and 2020 featuring the distinct diamond-shaped headlight unit.
This larger master cylinder body will NOT clear the inner plastic dashboard surround panels on early 2005–2011 faired GTR models when the handlebars hit full left steering lock. If you are rebuilding one of these specific early models, contact our team directly before placing an order so we can source a compact alternative layout for you.
59600HR7700, 59600-35C03, 59687-35C00, 59669-36510, 59610-35C00, 59691-35C00, 59600HP9203, 59600HP9201, 59600HN9102
🔧 Workshop Verified Reference
Below is our own workshop photographic proof documenting this direct installation path on a local club member’s custom machine, highlighting the visual spacing between the updated nose configurations:
| GTR 2012–2020 (RC Revisions) ✔ FULLY COMPATIBLE  |
GTR 2005–2011 (Early Fairings) ❌ NOT COMPATIBLE  |
To achieve the most immediate improvement from this high-pressure cylinder, couple the hydraulic swap with a set of stainless steel **Braided Brake Lines**. Standard vintage rubber lines flex and swell significantly when squeezed hard, while steel braids lock in the internal force to translate every ounce of piston effort directly down to your pads.
🔧 Safety & Installation Tips
- Hydraulic Competence: Front brake components dictate your safety. If you lack fluid bench-bleeding tools or have never manually cleared air locks out of twin-disc lines, have a professional bike mechanic do the job.
- Fluid Handling: Use only fresh, unsealed fluid from a fresh bottle of DOT 4. Seal the cap tightly between pumps; open hydraulic fluid absorbs environmental ambient moisture rapidly, which lowers its boiling point.
- Full Steering Lock Check: Once the fluid lines are torqued down, pivot your handlebars slowly from left stop to right stop before riding. Verify that no hoses stretch tight, bind, or press against structural frame points.
If you want to verify your front brake switch loom wire spacing or need help selecting the correct banjo crush washers for your build, drop us an email. For bleeding diagrams, custom assembly walk-throughs, or build opinions from fellow owners, head to the forums.
Additional information
| Weight | 2 kg |
|---|---|
| Dimensions | 30 × 25 × 7 cm |
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GARAGE PICKS // ADD TO BUILD
-
Brake Disc Rotor Bolts [x6] – Hyosung GT125R GT650 GV250 RX125 GT250 TE450
£12.99 -
TiTANIUM (Ti) Brake Disc Rotor Bolts – Hyosung GT125R GT650 GV250 GT250
£23.99 -
Braided Stainless Steel Front Brake Line x2 [Hose Kit] – Hyosung GT250R GT650R (& GT125R – Twin Disc)
£79.99 -
Braided Stainless Steel Front Brake Line x1 [Hose Kit] – Hyosung GT125R (GTR)
£59.99
EXPLORE // RELATED PRODUCTS
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Complete Stainless Steel Engine Bolt Kit – Hyosung GT GT125R GV125 GT250R GV250
Price range: £18.00 through £21.00 -
Japan D.I.D Cam Shaft Chain – Hyosung GT250 GV250 RX125 RT125
£79.99 -
Genuine Chrome Engine Oil Filter Cover Cap – GT125R GV125 GV250 GT250 Hyosung
£22.00 -
Heavy Duty Clutch Springs Set [x5] – Hyosung GV125 GT125 GT125R
£19.99
Independent Shop supplying ride enhancements and quality spares with fast dispatch. Need assistance? Access our workshop guides, manuals, tutorials or drop by the forums for troubleshooting help.
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