{"product_id":"royal-enfield-air-filter-521172a-thunderbird-350-350x-uce-bs4","title":"Royal Enfield Air Filter Element – UCE for Thunderbird 350 \u0026 Thunderbird 350X (BS-IV\/ABS) — 521172\/A | Genuine OE","description":"\u003cp data-start=\"834\" data-end=\"1446\"\u003eKeep your \u003cstrong data-start=\"844\" data-end=\"899\"\u003eThunderbird 350 \/ Thunderbird 350X (UCE)\u003c\/strong\u003e breathing clean with the \u003cstrong data-start=\"925\" data-end=\"989\"\u003egenuine Royal Enfield Air Filter Element — Part No. 521172\/A\u003c\/strong\u003e. This OE element is the \u003cstrong data-start=\"1014\" data-end=\"1077\"\u003efactory-specified filter for UCE Thunderbird  variants\u003c\/strong\u003e, ensuring correct airflow, filtration and idle quality without any rejetting or ECU changes when the intake\/exhaust are stock. Because it’s \u003cstrong data-start=\"1218\" data-end=\"1225\"\u003eOEM\u003c\/strong\u003e, the media density, sealing lip and overall dimensions match the original housing—so it’s a clean, drop-in replacement that maintains mileage and protects rings, valves and throttle response in dusty Indian conditions.\u003c\/p\u003e\n\u003cp data-start=\"1448\" data-end=\"1944\"\u003eThis listing is \u003cstrong data-start=\"1464\" data-end=\"1483\"\u003estrictly scoped\u003c\/strong\u003e to \u003cstrong data-start=\"1487\" data-end=\"1523\"\u003eThunderbird 350 (UCE,)\u003c\/strong\u003e and \u003cstrong data-start=\"1528\" data-end=\"1565\"\u003eThunderbird 350X (UCE)\u003c\/strong\u003e per the Royal Enfield spares portal evidence you provided. It is \u003cstrong data-start=\"1631\" data-end=\"1638\"\u003enot\u003c\/strong\u003e for J-Series models (Classic Reborn\/Meteor\/Hunter) and \u003cstrong data-start=\"1694\" data-end=\"1701\"\u003enot\u003c\/strong\u003e for older non-UCE Thunderbird airboxes that used different filter formats. Choose genuine to avoid fitment surprises and reduce returns.\u003cbr data-start=\"1838\" data-end=\"1841\"\u003e\u003cstrong data-start=\"1841\" data-end=\"1866\"\u003eName\/PN confirmation:\u003c\/strong\u003e \u003cstrong data-start=\"1867\" data-end=\"1906\"\u003e“AIR FILTER ELEMENT T1 — 521172\/A.\u003c\/strong\u003e\u003c\/p\u003e\n\u003ch2 data-start=\"1946\" data-end=\"1961\"\u003eKey Features\u003c\/h2\u003e\n\u003cul data-start=\"1962\" data-end=\"2393\"\u003e\n\u003cli data-start=\"1962\" data-end=\"2052\"\u003e\n\u003cp data-start=\"1964\" data-end=\"2052\"\u003e\u003cstrong data-start=\"1964\" data-end=\"1978\"\u003eGenuine OE\u003c\/strong\u003e Royal Enfield element — \u003cstrong data-start=\"2003\" data-end=\"2015\"\u003e521172\/A\u003c\/strong\u003e for \u003cstrong data-start=\"2020\" data-end=\"2049\"\u003eUCE Thunderbird BS-IV\/ABS\u003c\/strong\u003e.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2053\" data-end=\"2102\"\u003e\n\u003cp data-start=\"2055\" data-end=\"2102\"\u003eDirect \u003cstrong data-start=\"2062\" data-end=\"2073\"\u003edrop-in\u003c\/strong\u003e fit; no trimming or hacks.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2103\" data-end=\"2173\"\u003e\n\u003cp data-start=\"2105\" data-end=\"2173\"\u003eOE paper media \u0026amp; pleat geometry for stable fueling and filtration.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2174\" data-end=\"2247\"\u003e\n\u003cp data-start=\"2176\" data-end=\"2247\"\u003eHelps maintain mileage and throttle response in city and touring use.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2248\" data-end=\"2326\"\u003e\n\u003cp data-start=\"2250\" data-end=\"2326\"\u003eBuilt for dusty conditions; replace per schedule (earlier if severe dust).\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2327\" data-end=\"2393\"\u003e\n\u003cp data-start=\"2329\" data-end=\"2393\"\u003eTight scoping (TB\/TBX UCE BS-IV) to \u003cstrong data-start=\"2365\" data-end=\"2392\"\u003eavoid misorders\/\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 data-start=\"2395\" data-end=\"2435\"\u003eCompatibility Table (Confirmed Scope)\u003c\/h2\u003e\n\u003cdiv class=\"_tableContainer_1rjym_1\"\u003e\n\u003cdiv class=\"group _tableWrapper_1rjym_13 flex w-fit flex-col-reverse\" tabindex=\"-1\"\u003e\n\u003ctable data-start=\"2436\" data-end=\"2778\" class=\"w-fit min-w-(--thread-content-width)\"\u003e\n\u003cthead data-start=\"2436\" data-end=\"2482\"\u003e\n\u003ctr data-start=\"2436\" data-end=\"2482\"\u003e\n\u003cth data-start=\"2436\" data-end=\"2444\" data-col-size=\"sm\"\u003eModel\u003c\/th\u003e\n\u003cth data-start=\"2444\" data-end=\"2462\" data-col-size=\"sm\"\u003eEngine\/Platform\u003c\/th\u003e\n\u003cth data-start=\"2462\" data-end=\"2473\" data-col-size=\"sm\"\u003eBS Stage\u003c\/th\u003e\n\u003cth data-start=\"2473\" data-end=\"2482\" data-col-size=\"md\"\u003eNotes\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody data-start=\"2502\" data-end=\"2778\"\u003e\n\u003ctr data-start=\"2502\" data-end=\"2651\"\u003e\n\u003ctd data-start=\"2502\" data-end=\"2530\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"2504\" data-end=\"2529\"\u003eThunderbird 350 (UCE)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-start=\"2530\" data-end=\"2543\" data-col-size=\"sm\"\u003e346 cc UCE\u003c\/td\u003e\n\u003ctd data-start=\"2543\" data-end=\"2555\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"2545\" data-end=\"2554\"\u003eBS-IV,3\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-start=\"2555\" data-end=\"2651\" data-col-size=\"md\"\u003eABS\/BS-IV variants (official portal mapping confirms 521172\/A). \u003cem data-start=\"2621\" data-end=\"2649\"\u003e(Per screenshot supplied.)\u003c\/em\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"2652\" data-end=\"2778\"\u003e\n\u003ctd data-start=\"2652\" data-end=\"2681\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"2654\" data-end=\"2680\"\u003eThunderbird 350X (UCE)\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-start=\"2681\" data-end=\"2694\" data-col-size=\"sm\"\u003e346 cc UCE\u003c\/td\u003e\n\u003ctd data-start=\"2694\" data-end=\"2710\" data-col-size=\"sm\"\u003e\u003cstrong data-start=\"2696\" data-end=\"2709\"\u003eBS-3,IV\/ABS\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd data-start=\"2710\" data-end=\"2778\" data-col-size=\"md\"\u003eUses same UCE Thunderbird BS-IV airbox family; 521172\/A applies.\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp data-start=\"2780\" data-end=\"2818\"\u003e\u003cstrong data-start=\"2780\" data-end=\"2816\"\u003eExclusions (to prevent returns):\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul data-start=\"2819\" data-end=\"3053\"\u003e\n\u003cli data-start=\"2819\" data-end=\"2899\"\u003e\n\u003cp data-start=\"2821\" data-end=\"2899\"\u003e\u003cstrong data-start=\"2821\" data-end=\"2833\"\u003eJ-Series\u003c\/strong\u003e (Classic 350 Reborn, Meteor, Hunter) — different filter family.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2900\" data-end=\"2977\"\u003e\n\u003cp data-start=\"2902\" data-end=\"2977\"\u003e\u003cstrong data-start=\"2902\" data-end=\"2925\"\u003ePre-UCE Thunderbird\u003c\/strong\u003e (older “T1” canister families differ by housing).\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli data-start=\"2978\" data-end=\"3053\"\u003e\n\u003cp data-start=\"2980\" data-end=\"3053\"\u003e\u003cstrong data-start=\"2980\" data-end=\"3010\"\u003eClassic\/Bullet\/Electra UCE\u003c\/strong\u003e — typically use a different panel element.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 data-start=\"3055\" data-end=\"3066\"\u003eVariants\u003c\/h2\u003e\n\u003cp data-start=\"3067\" data-end=\"3150\"\u003eSingle item: \u003cstrong data-start=\"3080\" data-end=\"3113\"\u003e521172\/A – Air Filter Element\u003c\/strong\u003e (Qty 1). No LH\/RH or color variants.\u003c\/p\u003e\n\u003ch2 data-start=\"3152\" data-end=\"3159\"\u003eFAQs\u003c\/h2\u003e\n\u003cp data-start=\"3160\" data-end=\"3286\"\u003e\u003cstrong data-start=\"3160\" data-end=\"3203\"\u003eQ1. Will this fit Thunderbird 350X ABS?\u003c\/strong\u003e\u003cbr data-start=\"3203\" data-end=\"3206\"\u003eYes—this listing is scoped for \u003cstrong data-start=\"3237\" data-end=\"3266\"\u003eUCE Thunderbird BS-IV\/ABS\u003c\/strong\u003e, including \u003cstrong data-start=\"3278\" data-end=\"3285\"\u003eTBX\u003c\/strong\u003e.\u003c\/p\u003e\n\u003cp data-start=\"3288\" data-end=\"3415\"\u003e\u003cstrong data-start=\"3288\" data-end=\"3337\"\u003eQ2. I have Classic\/Bullet UCE—can I use this?\u003c\/strong\u003e\u003cbr data-start=\"3337\" data-end=\"3340\"\u003eNo. Those use a different OEM element; order the model-specific UCE filter.\u003c\/p\u003e\n\u003cp data-start=\"3417\" data-end=\"3523\"\u003e\u003cstrong data-start=\"3417\" data-end=\"3459\"\u003eQ3. Do I need tuning after installing?\u003c\/strong\u003e\u003cbr data-start=\"3459\" data-end=\"3462\"\u003eNo. It’s OE spec. Keep intake\/exhaust stock for best results.\u003c\/p\u003e\n\u003cp data-start=\"3525\" data-end=\"3652\"\u003e\u003cstrong data-start=\"3525\" data-end=\"3563\"\u003eQ4. How often should I replace it?\u003c\/strong\u003e\u003cbr data-start=\"3563\" data-end=\"3566\"\u003eFollow the service schedule; replace sooner in dusty conditions to protect the engine.\u003c\/p\u003e","brand":"UNDER THE HOOD","offers":[{"title":"Default Title","offer_id":50490981712167,"sku":null,"price":178.0,"currency_code":"INR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0878\/7447\/0183\/files\/F3C9F914-88E8-463E-830B-E390C310ED0E.jpg?v=1759582330","url":"https:\/\/underthehood.co.in\/products\/royal-enfield-air-filter-521172a-thunderbird-350-350x-uce-bs4","provider":"UNDER THE HOOD","version":"1.0","type":"link"}