{"about":"Prices are for United Kingdom in GBP. Every URL here is a plain path you can fetch directly.","product":{"basketKey":"8e8ad7a421a7","name":"BRC YAMAHA 500cc CONVERSION KIT 1999-2025, BOLT IN 500CC CONVERSION","sku":"BRC-YZM500_99-21","brand":"No Brand","mpn":null,"gtin":null,"condition":"new","inStock":true,"stock":2,"price":{"amount":7750.21,"formatted":"£7,750.21"},"summary":"Yamaha 500cc conversion kit. This is a bolt-in 500cc counterbalanced 2-stroke conversion based on the YZ250 platform. Requires components from a donor Yamaha YZ250 engine from 1999-2025. Delivers strong motocross-focused performance with smooth, linear power delivery. Features a pneumatic power valve system and a triple blade power valve for improved bottom-end performance. Accepts donor Yamaha YZ250 and YZ250X transmission components. Remains kick-start compatible with a decompression button fitted to aid starting. Includes a dedicated exhaust pipe and silencer. Fits 2005-2025 aluminium frames without fabrication. 1999-2004 steel frames require minor modification. Designed to use the stock carburettor. Engine capacity is 499cc, producing 60+ hp and 50+ ft-lb torque. Features an integral counterbalance shaft to reduce vibration.","attributes":[],"image":"https://b69270dd6ab1.blob.upstash.io/oracle/oro2u/BRC-YZM500_5F99-21/2f9098cb14064baa.jpg","images":["https://b69270dd6ab1.blob.upstash.io/oracle/oro2u/BRC-YZM500_5F99-21/2f9098cb14064baa.jpg"],"description":"Yamaha 500cc conversion kit. This is a bolt-in 500cc counterbalanced 2-stroke conversion based on the YZ250 platform. Requires components from a donor Yamaha YZ250 engine from 1999-2025. Delivers strong motocross-focused performance with smooth, linear power delivery. Features a pneumatic power valve system and a triple blade power valve for improved bottom-end performance. Accepts donor Yamaha YZ250 and YZ250X transmission components. Remains kick-start compatible with a decompression button fitted to aid starting. Includes a dedicated exhaust pipe and silencer. Fits 2005-2025 aluminium frames without fabrication. 1999-2004 steel frames require minor modification. Designed to use the stock carburettor. Engine capacity is 499cc, producing 60+ hp and 50+ ft-lb torque. Features an integral counterbalance shaft to reduce vibration.","descriptionMarkdown":"### BRC 500cc Two-Stroke Conversion Kit for Yamaha YZ250 Platform\n\n Transform your Yamaha YZ250 into a powerful 500cc machine with this bolt-in conversion kit. Designed for motocross enthusiasts, this kit delivers strong performance with smooth, linear power delivery, enhancing your riding experience. It utilizes a counterbalanced two-stroke design based on the YZ250 platform, requiring components from a donor Yamaha YZ250 engine.\n\n#### Key Features:\n\n \n- Bolt-in 500cc counterbalanced two-stroke conversion.\n \n- Requires donor Yamaha YZ250 engine components.\n \n- Engineered for potent motocross-focused power delivery.\n \n- Features a pneumatic power valve system for smooth, linear power.\n \n- Includes a triple blade power valve for improved bottom-end performance.\n \n- Compatible with donor Yamaha YZ250 and YZ250X transmission components.\n \n- Retains kick-start functionality.\n \n- Equipped with a decompression button for easier starting.\n \n- Comes with a dedicated exhaust pipe and silencer designed for optimal fit and performance.\n \n- Integral counterbalance shaft significantly reduces vibration for a smoother ride.\n \n- Designed to integrate seamlessly with the stock carburettor for optimal fuel delivery.\n\n#### Performance Specifications:\n\n \n- Engine Capacity: 499cc\n \n- Horsepower: 60+ hp\n \n- Torque: 50+ ft-lb\n\n#### Installation Notes:\n\n This kit is designed for direct bolt-in installation on 2005-2025 aluminium frame models without the need for fabrication. For 1999-2004 steel frame models, minor modification will be required.","weightGrams":null,"fitments":[],"collections":[],"links":{"page":"https://www.2brosparts.com/products/brc-yamaha-500cc-conversion-kit-1999-2025-bolt-in-500cc-conversion","buyOneNow":"https://www.2brosparts.com/api/agent/checkout/GB/8e8ad7a421a7:1","basketWithThis":"https://www.2brosparts.com/api/agent/basket/GB/8e8ad7a421a7:1"}},"market":{"country":"GB","countryName":"United Kingdom","locale":"en-gb","currency":"GBP","exchangeRateFromGbp":1,"pricesIncludeUkVat":true,"checkoutTax":null,"delivery":[{"name":"Standard","description":"Orders £15.00–£59.99 · 2–4 business days","carrier":null,"estimatedDays":"2–4 business days","price":{"amount":4.99,"formatted":"£4.99"},"free":false,"minimumOrder":{"amount":0,"formatted":"£0.00","gbp":0},"weightGrams":null},{"name":"Standard","description":"Orders £60.00 and up · 2–4 business days","carrier":null,"estimatedDays":"2–4 business days","price":{"amount":0,"formatted":"£0.00"},"free":true,"minimumOrder":{"amount":60,"formatted":"£60.00","gbp":60},"weightGrams":null}],"storeUrl":"https://www.2brosparts.com"},"navigate":{"start":"https://www.2brosparts.com/api/agent","search":"https://www.2brosparts.com/api/agent/search/GB/{words+joined+with+plus}"},"howToBuy":{"summary":"Build a basket for the shopper and give them one checkout link. Every URL is a plain path (no query string) and a GET. Nothing is stored between calls.","checkoutLinkFormat":"https://www.2brosparts.com/api/agent/checkout/GB/{basketKey}:{quantity},{basketKey}:{quantity}","steps":["1. Find products: follow links in these responses, or fetch https://www.2brosparts.com/api/agent/search/GB/{words+joined+with+plus} (e.g. https://www.2brosparts.com/api/agent/search/GB/brake+pads). Every product has a basketKey.","2. Optional check: https://www.2brosparts.com/api/agent/basket/GB/{basketKey}:{quantity},{basketKey}:{quantity} returns stock, totals per delivery option and the checkout link.","3. Give the shopper the checkout link. Opening it fills their basket with exactly these items (replacing what was there) and opens checkout for United Kingdom. They pay on 2brosparts.com through Stripe."],"noFetchNeeded":"You can write the checkout link yourself from basketKeys and quantities; nothing has to be fetched first. Each product also has links.buyOneNow, a ready link for one unit.","stateless":"Nothing is saved on our side. The items part of the URL is the whole basket: to change it, write the link again with the new list.","itemsFormat":"basketKey:quantity pairs joined by commas, e.g. 04f24aad4d68:2,7c1e9a0b3f2d:1. Quantity defaults to 1. Up to 50 products, 100 each.","country":"GB is the shopper's delivery country. Swap it for theirs (US, DE, FR…) in any URL; currency, tax and delivery follow it.","tips":["Put everything the shopper wants in one link.","Optionally add your name as a last path segment on checkout links (…/checkout/GB/<items>/claude) so the sale is credited to you.","The checkout link is for the shopper's browser. Do not open it yourself.","Signed-in trade account holders see their trade prices at checkout."]}}