UCAL BS29-19 Carburettor Assembly for Royal Enfield 350 UCE BS3 – Thunderbird / Classic / Bullet / Electra (570282/H)

If your old carb has become jerky, hard to tune, or your Thunderbird / Classic / Bullet 350 has started misfiring and drinking fuel, this UCAL BS29-19 Carburettor Assembly is the OEM-spec fix. UCAL is the original carburettor supplier to Royal Enfield for the 350 UCE BS3 range, and this BS29-19 assembly (customer code 570282/H) is built to restore factory-correct fuelling, smooth idle and crisp throttle response on carbureted 350cc twinspark engines.

Designed around the proven BS29 constant-vacuum (CV) 29 mm carburettor platform, this unit delivers a stable air-fuel mixture across city traffic, highway cruising and loaded touring. Riders coming from tired, worn carbs will immediately feel easier cold starts, cleaner pickup and fewer flat spots.

Unlike generic “Bullet carb” duplicates, this is an OEM-vendor UCAL assembly matched to Royal Enfield 350 UCE BS3 models using the BS29 carb – including Thunderbird 350 UCE and other 350 UCE twinspark carb variants.

Buying from Under The Hood (underthehood.co.in) means you get genuine parts sourced from trusted channels, careful packaging, and support from a real Royal Enfield-focused workshop in Varanasi. Pair this carb with correct jetting, a healthy air filter and proper chain & sprocket maintenance, and your 350 will feel closer to how it left the factory – ready for daily commutes and long tours alike.

Key Features 

• Genuine UCAL BS29-19 carburettor assembly – OEM vendor for Royal Enfield 350 UCE BS3 motorcycles (REL code 570282/H).

• Correct BS29 CV design (≈29 mm venturi) for smooth, progressive throttle response and improved rideability vs worn or undersized carbs.

• Direct replacement for stock BS29 units on 350 UCE twinspark carb models – no fabrication or frame cuts required.

• Factory-style idle and mixture control, helping reduce jerks, stalling and erratic idling when set up correctly.

• Built with OEM-grade materials (aluminium body, brass internals, precise jets, rubber seals) for durability and consistent fuelling.

• Restores cold start performance & fuel efficiency compared to clogged, locally repaired or non-OEM carbs.

• Suitable for city, highway and touring use with pillion and luggage when tuned to stock or mild-upgrade setups (OE or mild free-flow exhaust).

• UCAL / Royal Enfield training documentation lists this carb as application for REL 350 cc all models, ensuring wide 350 UCE BS3 coverage when matched by BS29 stamping.

• Sold by Under The Hood, an enthusiast workshop & e-commerce store specialising in Royal Enfield parts, with safe packaging and video-friendly unboxing policy.

• Ideal base for carb refresh jobs and restoration builds on older 350 UCE bikes running the BS29 platform.

Compatibility Table
(Only BS3 carb / BS29-equipped 350 UCE models confirmed. Always match existing carb stamping “BS29” and REL code 570282/H before ordering.)

*Years are BS3 carbureted production years; these vary by market. If your bike is BS4 or EFI, this carb will not be a direct fit.

Caution Note:
If your motorcycle has UCD33/UCD29 carb or Keihin EFI, this UCAL BS29-19 will not be a plug-and-play replacement. Check your existing carb model and consult your mechanic before ordering.

Variants 

This product page is for the complete UCAL BS29-19 carburettor assembly only (single standard variant).

If you want related options, consider creating/bundling on your store (for cross-sell, not as variants on this SKU):

• BS29 Carb Minor Kit (888224) – jets, gaskets and small parts for overhauling an existing BS29 carb.

• BS29-19 Major Kit (888225) – full repair kit where the body is OK but internals are worn.

What’s in the Box

• 1 x UCAL BS29-19 Carburettor Assembly (complete CV carb with body, slide/diaphragm, float bowl, jets and standard adjusters – as supplied by UCAL).

Not included: inlet manifold, air filter box, throttle cable, fuel hose, clamps or mounting gaskets – reuse your existing hardware or buy separately as needed.

Installation & Maintenance Notes

• Recommended to be installed by a qualified Royal Enfield mechanic – correct throttle cable routing, vacuum connections and fuel line routing are critical.

• Before fitment, compare with your existing carb: flange pattern, BS29 marking, and overall orientation must match.

• After installation, set idle speed and mixture as per manufacturer spec; fine-tune based on plug colour and ride feel.

• If you use a free-flow exhaust or air filter, rejetting may be required for ideal AFR and engine safety.

• Use only clean, filtered petrol and keep the air filter in good condition to prevent jet clogging.

• Periodically clean the float bowl and jets if the bike sits unused, and always drain fuel before long storage.

• Combine with regular spark plug, chain & sprocket and oil changes for best overall performance – you can link to your maintenance blogs / kits here.

FAQs 

1. Will this UCAL BS29-19 carb fit my Royal Enfield Thunderbird 350 BS3?
   Yes. UCAL’s own catalogue lists BS29-19 (REL code 570282/H) for the Royal Enfield Thunderbird 350CC BSIII using the BS29 carb platform. As long as your bike is a carbureted BS3 Thunderbird 350 with BS29 carb from factory, this is a direct replacement.

2. Can I use this carb on my Classic 350 / Bullet 350 / Electra 350 UCE?
   UCAL training documents mention application “REL 350 cc all models”, and Royal Enfield major/minor kits for BS29-19 cover Classic 350, Bullet 350 UCE (KS/ES) and Electra 350 UCE (ES). If your 350 UCE is BS3 and already running a BS29 carb, this assembly is typically compatible. Always confirm by checking your stock carb stamping and consulting your mechanic.

3. Is this an original UCAL product or a local duplicate?
   This is a genuine UCAL OEM-vendor carburettor, the same brand that supplies carbs for Royal Enfield 350 UCE models. Under The Hood sources directly from trusted distributors; we do not deal in local copies or “repair carbs”. Packaging, casting quality and markings reflect OEM standards.

4. Will this carb improve power or mileage compared to my old unit?
   If your existing carb is worn, leaking or badly tuned, a fresh OEM-spec UCAL BS29-19 can noticeably improve starting, idling, throttle response and fuel efficiency, bringing the bike closer to stock performance. It is not a “performance racing carb”, but it removes performance loss caused by a tired or incorrect carb.

5. Do I need any extra parts to install this on my bike?
   In most cases, your stock inlet manifold, air box, fuel hose and throttle cable are reused. If any of these are cracked or worn, we recommend changing them at the same time. Gaskets and hoses are not included in this box – you can add them from our Royal Enfield 350 UCE spares category when ordering.