Genuine Royal Enfield One-Way Valve (1040409/C) – OEM Crankcase Breather / Check Valve for BS4 UCE 350cc Models

Product Description Maintain the efficiency of your engine’s ventilation system with the Genuine Royal Enfield One-Way Valve. This essential OEM component (Part No: 1040409/C) is a small but critical check valve integrated into the breather line of BS4-compliant Unit Construction Engines (UCE). The 1040409/C functions as a “directional gatekeeper” for the crankcase. It allows air and oil fumes to escape the crankcase into the airbox but prevents them from flowing backward into the engine. This one-way action reduces internal pressure, prevents oil mist from fouling the air filter, and helps maintain a stable engine idle. As a genuine Royal Enfield part, it is made from heat-resistant plastic to withstand the high operating temperatures of air-cooled engines and is designed for a direct push-fit into the original rubber breather hoses. Key Features: OEM Breather Control: 100% authentic Royal Enfield part, ensuring the correct valve opening pressure for BS4 emissions standards. Directional Flow: Effectively vents crankcase pressure while blocking the return of oily vapors and contaminants. Durable Materials: Constructed from oil- and heat-resistant plastic with a secure, leak-proof internal diaphragm. Direct Installation: Designed as a simple push-fit replacement for the standard breather hose assembly. Idle Stability: Helps prevent erratic idling and “stalling” issues often caused by incorrect crankcase pressure or vacuum leaks. Product Specifications: Brand: Royal Enfield Genuine Parts Part Number: 1040409/C (Supersedes 1040409) Material: High-Grade Polymer Color: Black / Blue accents Compatibility: ✅ Royal Enfield Classic 350 BS4 (≈2016–2020) ✅ Royal Enfield Bullet 350 / Standard 350 BS4 ✅ Royal Enfield Bullet 350 ES BS4 ✅ Royal Enfield Electra 350 BS4 ✅ Royal Enfield Thunderbird 350 BS4 ❌ Note: Not compatible with the newer J-Series (Meteor/Hunter) or 650 Twins.