{"product_id":"akrapovic-evolution-line-titanium-yamaha-yz450f-s-y4met16-fdhlta","title":"Akrapovic Evolution Line Titanium Yamaha YZ450F (2023-2025) – S-Y4MET16-FDHLTA","description":"\u003cp\u003e56.6 horsepower. That is the highest figure of any motocross system in this catalogue, and it comes from Yamaha's reversed-cylinder 450 — the engine that turned the class on its head when it appeared, with the intake at the front and the exhaust running back and down.\u003c\/p\u003e\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eTitanium complete system for the 2023 to 2025 YZ450F\u003c\/li\u003e\n\u003cli\u003e56.6 PS at 10,600 rpm, 1.9 above the standard 54.7\u003c\/li\u003e\n\u003cli\u003e3.32 kg instead of 4.17 kg — 850 grams less\u003c\/li\u003e\n\u003cli\u003eTorque 45.8 Nm, up from 45.5\u003c\/li\u003e\n\u003cli\u003eThe most powerful motocross setup listed here\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eThe reversed cylinder\u003c\/h2\u003e\n\u003cp\u003eYamaha turned the cylinder around on the YZ450F: the airbox sits where the tank used to be, the intake is straight and short, and the exhaust leaves at the rear before wrapping forward. It gives the header an unusual shape and a longer run than on a conventional motocrosser.\u003c\/p\u003e\n\u003cp\u003eAn exhaust for this engine cannot be a generic pipe with different mounts. Akrapovic builds the header to the routing Yamaha's layout demands, and the 1.9 PS is what that specific work is worth.\u003c\/p\u003e\n\u003ch2\u003eWhere the 850 grams sit\u003c\/h2\u003e\n\u003cp\u003eHigh and behind the rider. On a 450 that is ridden aggressively, mass at the back of the bike affects how quickly the rear will come round and how the machine sits in the air. It is the same argument as on the Kawasaki, and it is the reason full systems outsell slip-ons in this class.\u003c\/p\u003e\n\u003ch2\u003eThree model years\u003c\/h2\u003e\n\u003cp\u003e2023, 2024 and 2025. Yamaha changed the 450 again for 2026, and that year takes S-Y4MET17-FDHLTA — a separate article with identical published figures.\u003c\/p\u003e\n\u003ch2\u003eNot for the road\u003c\/h2\u003e\n\u003cp\u003eClosed course competition only. There is no EC or ECE approval and no homologation document for this system.\u003c\/p\u003e\n\u003ch2\u003eWhy the header shape is the hard part\u003c\/h2\u003e\n\u003cp\u003eWith the exhaust port at the rear of the engine, the YZ450F header has to leave the head, turn forward under the frame, pass the shock and then run back to the silencer. That is more bends in less space than a conventional layout allows, and every bend costs flow if it is done badly.\u003c\/p\u003e\n\u003cp\u003eAkrapovic forms the pipe rather than assembling it from mandrel bends welded together. The wall stays a constant thickness through the curve and the internal diameter does not step, which is where the 1.9 PS comes from — not from a bigger pipe.\u003c\/p\u003e\n\u003ch2\u003eRiding a 450 with 850 grams less at the back\u003c\/h2\u003e\n\u003cp\u003eMass behind the rider and above the axle line is what resists the bike rotating in the air. Take almost a kilogram out of it and a scrub gets easier, a whip comes back sooner and a bad landing is less of an argument.\u003c\/p\u003e\n\u003cp\u003eNone of that shows up on a dyno sheet, which is precisely why full systems keep selling in a class where the power gains are measured in single horsepower.\u003c\/p\u003e\n\u003ch2\u003eFitting and what it needs\u003c\/h2\u003e\n\u003cp\u003eThe complete system replaces the header and the silencer. Akrapovic supplies the springs and mounts; a new exhaust port gasket is a Yamaha part and worth having on the bench before starting.\u003c\/p\u003e\n\u003ch2\u003eThree years, then a new number\u003c\/h2\u003e\n\u003cp\u003e2023, 2024 and 2025 take this article. From 2026 Akrapovic lists S-Y4MET17-FDHLTA with identical published figures — a different part for a changed chassis rather than a changed engine.\u003c\/p\u003e\n\u003ch2\u003eArticle number\u003c\/h2\u003e\n\u003cp\u003eAkrapovic lists this system as S-Y4MET16-FDHLTA. The optional noise damper for a 109 dB\/A limit is V-TUV386.\u003c\/p\u003e","brand":"Akrapovic","offers":[{"title":"Default Title","offer_id":53631837307146,"sku":"S-Y4MET16-FDHLTA","price":4743.0,"currency_code":"QAR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0949\/7831\/0410\/files\/01_c2de1f57-0a50-493d-9f7f-1098f16b4e8c.png?v=1788618319","url":"https:\/\/inter-pace.com\/en-qa\/products\/akrapovic-evolution-line-titanium-yamaha-yz450f-s-y4met16-fdhlta","provider":"Inter-Pace","version":"1.0","type":"link"}