aRacer Heavy-Duty ISG Stator Power Harness Upgrade Kit

Is your Yamaha 125cc/155cc liquid-cooled scooter suffering from charging system gremlins or melted stator plugs? The modern Yamaha B8R engine platform utilizes an advanced Integrated Starter Generator (ISG) system. Unfortunately, high electrical loads and continuous ISG motor startup surges frequently overload the factory wiring between the stator and the Motor Generator Unit (MGU / SGCU), causing severe connector melting, voltage drops, and sudden battery drainage.

Designed by global tuning authority aRacer SpeedTek, the aRacer ISG Upgraded Power Harness Kit is the ultimate preventive and performance replacement solution. Re-engineered from the ground up to solve factory electrical flaws, this heavy-duty harness protects your charging system while delivering tangible performance gains.

• Proven ~25°C (45°F) Temperature Reduction: Real-world thermal testing proves a dramatic 25°C drop in operating temperature at the connector plug, effectively eliminating the risk of melted housings and thermal arcing.

• 10% More Instant Current for eBoost: When eBoost or electric motor assist is activated, the harness allows a 10% increase in instantaneous current throughput, noticeably sharpening motor reaction and throttle response.

• Redesigned High-Contact Connector Pins: Features enlarged internal pin contacts that significantly increase electrical surface contact area, reducing resistance and preventing high-temp hotspots.

• EV-Grade Anti-Abrasion Braided Sleeving: The exterior is wrapped in electric-vehicle (EV) grade, high-tensile braided protective sleeving—delivering superior resistance against engine heat, oil, and chassis friction.

• High-Amperage Heavy Core Cable: Built with premium low-resistance inner conductors engineered specifically for continuous high-current power transfer.

• Universal ECU Compatibility: 100% compatible with stock bikes, factory OEM ECUs, or full-standalone aRacer Super X / RC Mini ECU setups.

Key Features & Benefits

• Fixes Known Factory ISG/MGU Weakness: Purpose-built preventive upgrade to eliminate burnt stator plugs on Yamaha B8R 125cc/155cc engines.

• Tested 25°C Thermal Drop: Substantially cools line temperatures under heavy riding conditions and auxiliary electrical loads.

• Boosts Motor Assistance: Delivers 10% more instant amperage during eBoost activation for crisper throttle response.

• Rugged EV-Grade Braided Jacket: Heavy-duty outer sleeving withstands extreme engine bay vibration, heat, and oil exposure.

• Enhanced Pin Surface Contact: Re-engineered terminals maximize current conductivity and eliminate micro-arcing.

• Direct Fitment: Designed specifically for seamless integration into the stock Yamaha B8R charging layout.

Technical Specifications

• Brand: aRacer SpeedTek (100% Authentic)

• Product Category: High-Current ISG / MGU Power Harness

• Outer Sleeve Material: EV-Grade Flame-Retardant Anti-Abrasion Braided Jacket

• Conductor Spec: High-Amperage Low-Resistance Copper Cable

• Thermal Performance: Approx. -25°C (~45°F) Connector Temp Reduction

• eBoost Current Gain: +10% Instantaneous Current Throughput

• ECU Compatibility: Stock ECU & aRacer ECU Compatible

• Origin: Made in Taiwan

Fitment Compatibility (Yamaha B8R Engine Platform)

• Yamaha Zuma 125 (2022–2026+ B8R Liquid-Cooled / US Models)

• Yamaha Cygnus Gryphus 125 (6th Gen)

• Yamaha Force 2.0 / Augur 155 / X FORCE 155