{"product_id":"twin-air-1-8-bar-radiator-pressure-cap-177900","title":"Twin Air - Replacement 1.8 Bar Radiator Pressure Cap","description":"\u003ch1\u003eTwin Air 1.8 Bar Replacement Radiator Pressure Cap\u003c\/h1\u003e\n\u003cp data-path-to-node=\"1\"\u003eThe Twin Air 1.8 Bar High-Pressure Radiator Cap (177900) is a critical cooling system upgrade designed to prevent coolant loss and engine overheating in high-demand off-road conditions. Stock motorcycle radiator caps are typically rated at 1.1 bar (15.9 psi), which allows engine coolant to boil at approximately 252°F (122°C). In slow-speed technical single-track, deep sand, or heavy mud, engine temperatures quickly surpass this threshold, causing the factory cap to vent and boil off coolant.\u003c\/p\u003e\n\u003cp data-path-to-node=\"2\"\u003eBy increasing internal cooling system pressure to 1.8 bar (26.1 psi), this high-pressure cap elevates the boiling point of water-based coolant to approximately 278°F (136°C). This higher threshold keeps the coolant in liquid form longer, ensuring continuous heat transfer away from the cylinder head and water jacket. Featuring an integrated temperature gauge on the top cap face, it allows riders and mechanics to instantly monitor real-time coolant temperatures without opening the hot pressurized system.\u003c\/p\u003e\n\u003ch4 data-path-to-node=\"3\"\u003eFeatures:\u003c\/h4\u003e\n\u003cul data-path-to-node=\"4\"\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"4,0,0\"\u003e\u003cb data-path-to-node=\"4,0,0\" data-index-in-node=\"0\"\u003eElevated Boiling Point:\u003c\/b\u003e Increases operating pressure to 1.8 bar (26.1 psi) to raise coolant boiling point and prevent boil-overs during hard riding.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"4,1,0\"\u003e\u003cb data-path-to-node=\"4,1,0\" data-index-in-node=\"0\"\u003eIntegrated Temperature Gauge:\u003c\/b\u003e Top-mounted dial thermometer provides immediate visual coolant temperature monitoring in both Celsius and Fahrenheit.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"4,2,0\"\u003e\u003cb data-path-to-node=\"4,2,0\" data-index-in-node=\"0\"\u003ePrevents Coolant Loss:\u003c\/b\u003e Stops pressure venting through the overflow hose, preserving fluid levels during low-speed, high-load technical trail sections.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"4,3,0\"\u003e\u003cb data-path-to-node=\"4,3,0\" data-index-in-node=\"0\"\u003eHeavy-Duty Spring \u0026amp; Seals:\u003c\/b\u003e Constructed with high-grade stainless steel springs and durable silicone rubber seals to resist heat degradation and chemical corrosion.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"4,4,0\"\u003e\u003cb data-path-to-node=\"4,4,0\" data-index-in-node=\"0\"\u003eDirect OEM Fitment:\u003c\/b\u003e Standard B-size cap dimensions drop directly onto radiator filler necks across major Japanese and European motorcycle models.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4 data-path-to-node=\"5\"\u003eWhat's in the Box:\u003c\/h4\u003e\n\u003cul data-path-to-node=\"6\"\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"6,0,0\"\u003e1x Twin Air 1.8 Bar Radiator Cap with Integrated Temperature Gauge (Part #177900)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4 data-path-to-node=\"7\"\u003eFitment Notes:\u003c\/h4\u003e\n\u003cul data-path-to-node=\"8\"\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"8,0,0\"\u003e\u003cb data-path-to-node=\"8,0,0\" data-index-in-node=\"0\"\u003eUniversal Standard Fitting:\u003c\/b\u003e Fits most modern dirt bikes, dual-sports, and adventure motorcycles equipped with standard \"B-Type\" radiator filler necks (including KTM, Husqvarna, GASGAS, Honda, Yamaha, Kawasaki, and Suzuki).\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"8,1,0\"\u003e\u003cb data-path-to-node=\"8,1,0\" data-index-in-node=\"0\"\u003eClearance Notice:\u003c\/b\u003e Verify overhead clearance between your radiator cap and aftermarket fuel tanks or oversized radiators prior to installation, as the integrated temperature gauge adds approximately 15mm in top height compared to flat stock caps.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cmeta charset=\"utf-8\"\u003e\n\u003cp data-path-to-node=\"12\"\u003e\u003cb data-path-to-node=\"12\" data-index-in-node=\"0\"\u003eThe Pressure Physics:\u003c\/b\u003e Increasing system pressure does not make the engine run colder; instead, it expands the operational window before the fluid physically changes state from liquid to steam. Steam pockets inside a cylinder head create severe localized hot spots because gas transfers heat far less efficiently than liquid. Elevating the system pressure to 1.8 bar keeps the coolant liquid under extreme thermal spikes, preserving proper heat dissipation through the radiator cores.\u003c\/p\u003e\n\u003cp data-path-to-node=\"13\"\u003e\u003cb data-path-to-node=\"13\" data-index-in-node=\"0\"\u003eCooling System Inspection:\u003c\/b\u003e Before installing a 1.8 bar cap on an older motorcycle, inspect the condition of your radiator hoses, hose clamps, and water pump gaskets. Increasing system pressure from 1.1 bar to 1.8 bar places higher stress on the entire cooling circuit. Weak, dry-rotted hoses or loose worm-gear clamps may weep under the elevated pressure. Always install fresh hose clamps or inspect soft lines when upgrading to a high-pressure cap.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003e\u003ca href=\"https:\/\/www.tmbrmoto.com\/collections\/twin-air\" title=\"Shop TMBR MOTO for Twin Air air filters, oil filters and other motorcycle parts. Keep your bike running at it best.\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0622\/5720\/1317\/files\/TWIN_AIR_BANNERS.jpg?v=1779211277\" alt=\"\"\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003ePart Number: 177900\u003cbr\u003e\u003cbr\u003e\u003c\/p\u003e","brand":"Twin Air","offers":[{"title":"Default Title","offer_id":50836354269349,"sku":"TWNAR-RAD-PRSR-CAP","price":35.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0622\/5720\/1317\/files\/Twin_Air_1.8_Bar_Radiator_Cap_177900.png?v=1792786951","url":"https:\/\/www.tmbrmoto.com\/products\/twin-air-1-8-bar-radiator-pressure-cap-177900","provider":"TMBR MOTO","version":"1.0","type":"link"}