{"product_id":"reds-521-sport-s-line-3-5cc-21","title":"REDS 521 Sport S-Line 3.5cc (.21)-REDCOBU0033","description":"\u003cdiv class=\"_description-left\"\u003e\n\u003cdiv class=\"_description-left\"\u003e\n\u003ch2\u003eInnovation, Quality \u0026amp; Performance .21 Nitro Engine\u003c\/h2\u003e\n\u003cp\u003eThe 521 Sport S-Line Off Road Nitro Engine Combo from REDS is engineered to deliver innovation, premium quality, and impressive performance at a mid-range street price. Designed for off-road competition and serious enthusiasts, this engine blends advanced materials with cutting-edge manufacturing processes. As part of the S-Line family alongside the 721 Scuderia, Superveloce, and Corsa models, it represents REDS’ commitment to precision and performance. Every engine is assembled in-house and 100% made in Italy to ensure superior craftsmanship and reliability.\u003c\/p\u003e\n\u003ch3\u003eAbout the 521 Sport S-Line Engine\u003c\/h3\u003e\n\u003cbr\u003e\n\u003ch4\u003eAdvanced Aluminum GEN2 Carburetor\u003c\/h4\u003e\n\u003cp\u003eThe 521 Sport is equipped with the same high-quality aluminum carburetor found on the 721 series, ensuring excellent tuning stability and long-term reliability. An upgraded aerospace-grade ultra high strength polymer insulator bushing enhances durability under extreme racing conditions. The GEN2 carburetor also features a double grab screw joint link, making installation and servo linkage positioning easier and more precise. This refined carburetion system delivers consistent throttle response and smooth drivability.\u003c\/p\u003e\n\u003ch4\u003eHigh-Stiffness Die-Cast Crankcase Design\u003c\/h4\u003e\n\u003cp\u003eREDS Racing developed an updated high-stiffness crankcase using a premium pressure die-casting process and a proprietary aluminum alloy. This advanced construction increases overall structural rigidity and strength, improving durability during demanding off-road racing. The precision-engineered crankcase enhances engine stability and performance consistency under high RPM loads. The result is a reliable platform built to withstand the rigors of competitive racing.\u003c\/p\u003e\n\u003ch4\u003e5-Port Technology with Handmade Precision\u003c\/h4\u003e\n\u003cp\u003eFeaturing advanced 5-port technology and a redesigned piston and sleeve materials, the 521 Sport delivers a smooth power band with excellent fuel efficiency. The optimized porting design improves fuel mileage while maintaining strong, usable power across the RPM range. Each engine is hand-inspected and compression-checked at REDS Racing headquarters by Mario Rossi to ensure the highest quality standards.\u003c\/p\u003e\n\u003ch3\u003eFeatures:\u003c\/h3\u003e\n\u003cul class=\"product-page-features\"\u003e\n\u003cli\u003e5-Port High Efficiency Design\u003c\/li\u003e\n\u003cli\u003eAluminum GEN2 Carburetor\u003c\/li\u003e\n\u003cli\u003eAerospace Grade Polymer Insulator\u003c\/li\u003e\n\u003cli\u003eDouble Grab Screw Joint Link\u003c\/li\u003e\n\u003cli\u003eHigh-Stiffness Die-Cast Crankcase\u003c\/li\u003e\n\u003cli\u003eProprietary Aluminum Alloy Construction\u003c\/li\u003e\n\u003cli\u003eSmooth And Linear Power Band\u003c\/li\u003e\n\u003cli\u003eExcellent Fuel Mileage\u003c\/li\u003e\n\u003cli\u003eHand Inspected And Compression Checked\u003c\/li\u003e\n\u003cli\u003e100% Made In Italy\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e","brand":"REDS","offers":[{"title":"REDCOBU0033B-w\/2143 Torque X-ONE Pipe \u0026 Pre-Break In by Mario Rossi","offer_id":43097632243755,"sku":"REDCOBU0033B","price":605.0,"currency_code":"CAD","in_stock":false},{"title":"REDCOBU0033-w\/2143 Torque X-ONE Pipe","offer_id":43097638830123,"sku":"REDCOBU0033","price":521.0,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0341\/7337\/files\/redcobu0033.jpg?v=1771888879","url":"https:\/\/mrgracing.ca\/products\/reds-521-sport-s-line-3-5cc-21","provider":"MRG Racing Canada","version":"1.0","type":"link"}