Royal Enfield Classic 350, Bullet 350, Electra & Thunderbird 350 E20 Carburettor Kit – UCE BS4 Silver Sticker – KLT00005/A

Genuine Royal Enfield E20 Carburettor Upgrade Kit – BS4 UCE 350

Own an older carburetted Royal Enfield Classic 350, Bullet 350, Electra 350 or Thunderbird 350? KLT00005/A is the genuine Royal Enfield E20 carburettor retrofit kit configuration identified for UCE 350 BS4 motorcycles, supplied with the silver fuel-tank label. It is intended for compatible pre-BS6 carburettor fuel systems being updated for use with petrol containing up to 20% ethanol (E20).

This listing is for the two-reference OEM kit combination, not a complete replacement carburettor assembly. Select it only after confirming the motorcycle has the appropriate UCE 350 BS4 carburettor and the silver-label kit specification.

Part identification

Exactly what is included

Important: The composition of the sealed KLT00002/A sub-kit is not independently itemised here. Do not assume the package contains a new complete carburettor, specified jets, hoses, gaskets or particular quantities of internal pieces unless confirmed from the genuine sealed pack. The two quantities shown above are from the supplied OEM kit breakdown.

Why consider an E20 retrofit?

E20 petrol contains up to 20% ethanol. On older fuel systems not originally configured for this blend, material compatibility of seals, hoses and other carburettor-associated components deserves attention. Royal Enfield has made E20 retrofit solutions available for eligible older BS3 and BS4 carburetted UCE motorcycles. A retrofit is intended to address fuel-system compatibility, not to serve as a universal cure for poor starting, low mileage, fuel leakage or rough idling; those symptoms also require proper diagnosis.

Model compatibility – choose by generation, not just name

These are the relevant older carburetted UCE model families, not blanket fitment guarantees for all years or variants. BS certification, carburettor type and OEM applicability must be checked for the specific motorcycle.

Do not order for

• UCE 350 BS3 models requiring the distinct BS3 E20 kit.
• BS6 / fuel-injected J-Series models such as the Classic 350 Reborn, Meteor 350, Hunter 350 or new Bullet 350.
• 500cc UCE motorcycles, EFI variants, or other engine capacities without specific OEM confirmation.
• Motorcycles requiring the black sticker configuration instead of this silver-label kit.
• Anyone needing a complete carburettor assembly, rather than an E20 upgrade kit.

Silver sticker vs black sticker: avoid the wrong kit

Do not substitute the BS3 carburettor kit for the BS4 version based on appearance alone. The label colour identifies the selected kit variant; it does not, by itself, establish the bike’s carburettor configuration.

Before ordering – four checks

1. Confirm the motorcycle is an older UCE 350 BS4 carburetted variant, not J-Series, BS3 or EFI.
2. Match the VIN / chassis number and original carburettor to the correct Royal Enfield EPC or authorised dealer reference.
3. Confirm the silver-sticker version KLT00005/A is required.
4. Review the exact kit number and check the existing fuel system’s condition with a competent mechanic.

Installation and practical guidance

Have the retrofit installed by a technician familiar with Royal Enfield UCE carburettors. The technician should inspect the fuel supply path and original carburettor, replace only the appropriate components according to genuine kit/service instructions, check for leakage and confirm normal idling and throttle response after service. Do not assume a new complete carburettor is supplied. No unverified jetting, torque, tuning or calibration specifications are provided here.

Frequently asked questions

1. Which Royal Enfield models is this kit for?

Applicable UCE 350 BS4 carburetted variants of the older Classic, Bullet, Electra and Thunderbird families, after VIN/EPC confirmation.

2. Does it fit Classic 350 Reborn?

No; Classic 350 Reborn uses the later J-Series fuel-injected platform.

3. Does it fit a BS3 Classic 350?

No. The BS3 version uses a different carburettor kit reference.

4. What is the difference between KLT00005/A and KLT00004/A?

Both are BS4 E20 kit variants, but this listing is specifically for the silver tank-label configuration.

5. Is KLT00002/A included?

Yes: the supplied breakdown specifies one KLT00002/A sub-kit.

6. Is the silver tank sticker included?

Yes: one RAK01706/A label appears in the supplied breakdown.

7. Does this contain a full carburettor?

A complete replacement carburettor is not specified in the breakdown and should not be assumed included.

8. Are jets, seals and fuel pipes included?

The internal bill of materials of KLT00002/A must be checked against the sealed genuine packet; individual internals are not promised here.

9. Will it solve a rough-idling or starting issue?

Not necessarily. Such symptoms may arise from several causes and need diagnosis.

10. Does this kit make any Royal Enfield compatible with E20?

No. Application is limited to matching older UCE 350 BS4 carburetted motorcycles.

11. Can I fit the kit myself?

Professional installation is recommended, followed by fuel-leak and operational checks.

12. How do I avoid ordering the wrong variant?

Verify BS generation, carburettor specification, VIN/EPC and silver-vs-black label requirement before purchase.

Ordering, claims and return information

Please verify model, generation, VIN, exact part number and included component references before ordering. Correctly supplied spare parts are generally not eligible for return due to incorrect selection, fitment assumption, incorrect diagnosis or change of mind, subject to applicable consumer law and store policy. For a damaged, missing or incorrect item, preserve the packaging and provide a complete unboxing video when raising a claim within 24 hours of delivery. Please review Under The Hood’s published return and cancellation policies.

Common buyer search names

Royal Enfield E20 kit BS4; Royal Enfield BS4 carburetor conversion kit; Classic 350 E20 upgrade kit; old Bullet 350 E20 petrol kit; Electra 350 carb E20 kit; Thunderbird 350 E20 fuel conversion; UCE 350 BS4 carb repair kit; genuine Royal Enfield KLT00005/A; silver sticker E20 kit; KLT00002/A carburettor retrofit.