Royal Enfield 570886/B – VB51 Carburettor Adaptor to Cylinder Head for Bullet 500, Classic 500 & Thunderbird 500 (UCE 500cc, EFI-to-Carb Manifold)

The Royal Enfield 570886/B – VB51 Adaptor Carburettor to Cylinder Head is the genuine OEM intake manifold / carb adaptor used on Royal Enfield 500cc UCE engines. Official parts lists describe this part as “VB51 – ADAPTOR CARBURETTOR TO CYL HEAD”, confirming it as the factory-spec connector between carburettor and cylinder head on the VB51 platform. 

Multiple trusted sellers list 570886/B specifically for Standard/Bullet 500, Classic 500 and Thunderbird 500 500cc UCE models, making it the correct choice for both stock VB51 carb setups and popular EFI-to-carb conversion builds on these motorcycles. 

Manufactured from durable, heat-resistant rubber/compound, this adaptor maintains proper air–fuel flow, angle and sealing between carb and head, preventing air leaks, erratic idling, flat spots and lean running. Upgrading a worn, cracked or hardened manifold with this genuine part restores throttle response and reliability, especially on tuned or long-distance bikes. Technical discussions and conversion guides for Classic 500 and other 500 UCE models also reference 570886/B as the correct intake manifold when converting EFI models to carburettor.

If you are rebuilding a 500 UCE engine, fixing intake leaks or performing an EFI-to-carb conversion on Bullet 500 / Classic 500 / Thunderbird 500, this OEM VB51 adaptor is the right and safest part to use—no jugaad, no guesswork, just factory-correct fitment.

Key Features 

• Genuine Royal Enfield OEM part – VB51 Adaptor Carburettor to Cylinder Head (Part No. 570886/B). 

• Designed for 500cc UCE engines used on Bullet 500, Classic 500 and Thunderbird 500. 

• Provides correct carb-to-head alignment and sealing, reducing intake air leaks and unstable idling. 

• Ideal for EFI-to-carb conversion projects on 500 UCE models using VB51 carburettor kits. 

• Heat- and fuel-resistant construction for long service life and consistent performance. 

• Direct replacement part – no modification required when used with compatible heads and VB51 carb. 

• Helps restore smooth throttle response and low-end torque on ageing or leaking manifolds.

• Backed by Royal Enfield OEM quality – same spec as supplied from factory.

Compatibility Table 

Core engine platform: 499cc single-cylinder UCE 500 (India & export markets).

CHECK PART NUMBER BEFORE PURCHASE

Variants

• Single Variant:

  • Royal Enfield 570886/B – VB51 Adaptor Carburettor to Cylinder Head (standard black/rubber finish)

(No LH/RH, color or size variants.)

FAQs

Q1. Will this fit my Classic 500 EFI from the factory?
ONLY CARBURETOR MODEL

Q2. Does it work for Thunderbird 500 / Rumbler 500?
Yes BUT CARBURETOR 500 CC MODEL 

Q3. Is this suitable for EFI-to-carb conversion on 500 UCE engines?
Yes. Classic 500 / Bullet 500 conversion builds frequently list 570886/B VB51 carburettor manifold as the specific part that connects the new carburettor to the original 500 UCE cylinder head.

Q4. Will this fit a 350cc UCE or GT 535?
NO THEY HAVE DIFFERENT PART NUMBERS 

Q5. How do I confirm this is the right part for my bike?
Match the part number on your existing manifold or cross-check 570886/B – VB51 Adaptor Carburettor to Cyl Head in the official Royal Enfield parts catalog for your exact model and year.