Brc 510cc Conversion Kit Yamaha YZ 250 1999-2025

Description

This BRC 510cc conversion kit is a bolt-in two-stroke engine conversion for Yamaha YZ250-based applications from 1999 to 2025, intended to build a larger-capacity counterbalanced engine by reusing selected parts from a donor YZ250 engine. In practical terms, it allows the original YZ250 platform to be rebuilt into a motocross-focused engine package with stronger output and smoother delivery, rather than relying on a complete replacement engine assembly.

Features

  • Bolt-in conversion based on the Yamaha YZ250 platform
  • Developed as a 500cc-class counterbalanced two-stroke conversion
  • Motocross-focused power delivery
  • Pneumatic power valve system for smooth, linear response
  • Triple-blade power valve arrangement for stronger bottom-end response
  • Kick-start compatible
  • Fitted decompression button to assist starting
  • Integral counterbalance shaft to reduce vibration
  • Supplied with a purpose-built exhaust pipe and silencer
  • Intended to run with the stock carburettor

Donor Components Required

  • Requires components from a donor Yamaha YZ250 engine from the listed applications
  • Reuses original engine parts to build the 510cc engine
  • Accepts donor Yamaha YZ250 and YZ250X transmission components
  • Donor engine parts used in the build include the clutch assembly, kicker assembly, water pump, intake, ignition and covers where possible

Specifications

  • Output: 60+ hp
  • Torque: 50+ ft-lb
  • Bore: 89 mm
  • Stroke: 80 mm
  • Compression ratio: 12.8:1
  • Transmission oil capacity: 1100 cc
  • Fuel requirement: minimum 91-octane petrol
  • Premix ratio: 50:1
  • Premix ratio for snowbike and desert use: 32:1

Cross-Reference OEM Part Numbers

  • Neutral switch block-off kit: 08-05-012
  • Service piston: Vertex 22447
  • Connecting rod: ProX 03.1406
  • Connecting rod: Wossner P2044
  • Left-side transmission output shaft cylindrical roller bearing: NJ205EC3
  • Equivalent replacement bearing: KTM 49030023000

Installation Notes

  • Both lower radiator fitting locations must be relocated using the supplied 6061-T6 caps and fittings
  • The donor YZ250 cylinder-head hose must be shortened to suit the taller cylinder
  • 2010 and older donor YZ250 engines require a neutral switch block-off kit
  • Uses readily available consumables including KTM-sourced bearings and seals, and gaskets made by Cometic

Vehicle Fitments

  • Yamaha YZ250, 2005-2025, aluminium frame models, fits without fabrication
  • Yamaha YZ250, 1999-2004, steel frame models, minor modification required

Brc 510cc Conversion Kit Yamaha YZ 250 1999-2025

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This BRC 510cc conversion kit is a bolt-in two-stroke engine conversion for Yamaha YZ250-based applications from 1999 to 2025, intended... Read more

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    SKU: BRC-YZM500_99-21

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    Description

    This BRC 510cc conversion kit is a bolt-in two-stroke engine conversion for Yamaha YZ250-based applications from 1999 to 2025, intended to build a larger-capacity counterbalanced engine by reusing selected parts from a donor YZ250 engine. In practical terms, it allows the original YZ250 platform to be rebuilt into a motocross-focused engine package with stronger output and smoother delivery, rather than relying on a complete replacement engine assembly.

    Features

    • Bolt-in conversion based on the Yamaha YZ250 platform
    • Developed as a 500cc-class counterbalanced two-stroke conversion
    • Motocross-focused power delivery
    • Pneumatic power valve system for smooth, linear response
    • Triple-blade power valve arrangement for stronger bottom-end response
    • Kick-start compatible
    • Fitted decompression button to assist starting
    • Integral counterbalance shaft to reduce vibration
    • Supplied with a purpose-built exhaust pipe and silencer
    • Intended to run with the stock carburettor

    Donor Components Required

    • Requires components from a donor Yamaha YZ250 engine from the listed applications
    • Reuses original engine parts to build the 510cc engine
    • Accepts donor Yamaha YZ250 and YZ250X transmission components
    • Donor engine parts used in the build include the clutch assembly, kicker assembly, water pump, intake, ignition and covers where possible

    Specifications

    • Output: 60+ hp
    • Torque: 50+ ft-lb
    • Bore: 89 mm
    • Stroke: 80 mm
    • Compression ratio: 12.8:1
    • Transmission oil capacity: 1100 cc
    • Fuel requirement: minimum 91-octane petrol
    • Premix ratio: 50:1
    • Premix ratio for snowbike and desert use: 32:1

    Cross-Reference OEM Part Numbers

    • Neutral switch block-off kit: 08-05-012
    • Service piston: Vertex 22447
    • Connecting rod: ProX 03.1406
    • Connecting rod: Wossner P2044
    • Left-side transmission output shaft cylindrical roller bearing: NJ205EC3
    • Equivalent replacement bearing: KTM 49030023000

    Installation Notes

    • Both lower radiator fitting locations must be relocated using the supplied 6061-T6 caps and fittings
    • The donor YZ250 cylinder-head hose must be shortened to suit the taller cylinder
    • 2010 and older donor YZ250 engines require a neutral switch block-off kit
    • Uses readily available consumables including KTM-sourced bearings and seals, and gaskets made by Cometic

    Vehicle Fitments

    • Yamaha YZ250, 2005-2025, aluminium frame models, fits without fabrication
    • Yamaha YZ250, 1999-2004, steel frame models, minor modification required

    Shipping & Delivery

    How long will my item take to arrive?

    Orders are typically dispatched within 1 working day and are shipped on a 24hour (non-guaranteed) service.

    Where do you ship to?

    We currently only ship orders within the UK.

    How can I track my order?

    Once your order has been dispatched, you will receive a tracking code. Tracking information is emailed to the email address that was provided when placing the order.

    Can I collect my order?

    Unfortunately we do not offer order collections from our fulfilment centre.

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