Royal Enfield 144039 – Decoke Gasket Kit (CAF Material) – 350cc Cast-Iron Bullet (Std / Deluxe / Machismo / Campus / Electra 4S–5S – Pre-UCE)

Royal Enfield part 144039 is the genuine Decoke Gasket Kit – CAF Material for 350cc cast-iron (CI) Bullet engines. Official Royal Enfield part lists describe it as “GASKET DE CARBONISI” / “GASKET KIT – CAF MATL.”, and classic catalogues and dealers sell it specifically as a 350cc de-carbonising gasket set for Indian-made Bullets.

Specialist suppliers like Hitchcock’s list 144039 as a “GASKET SET, INDIAN MADE 350cc, DECARBONISING, 1977–2007”, clearly positioning it as the top-end / decoke kit for 350cc CI Bullets, not a full engine set. The Spares Company and other vintage-RE sellers also label it as “Gasket Kit, Decarbonising” and confirm fitment across old-model 350 Bullets: Bullet 350 (1955), Deluxe (1986), Machismo (1989), Campus (1997), Electra 4S & 5S KS/ES (2005).

This kit includes the key top-end gaskets required when you decarbonise the head, lap valves or freshen up the piston / rings – typically head gasket, rocker box, exhaust flange and related joints – manufactured in CAF (asbestos-free fibre) and OE-spec materials for good sealing and heat resistance. It’s ideal when you are opening only the top end and don’t want to buy a full engine gasket set (which is part 144040).

Key Features

• Genuine Royal Enfield part 144039 – listed as “GASKET KIT – CAF MATL.” / “GASKET DE CARBONISI” in official price lists.

• Designed as a 350cc decoke / top-end gasket set for Indian-made Bullets (1977–2007).

• CAF (compressed asbestos-free fibre) and OE-grade materials – built for heat, oil and vibration in CI engines.

• Ideal for decarbonising and top-end refresh – head removal, valve work, piston/ring inspection.

• Factory-correct profiles for ports and stud patterns – less trimming and rework vs local kits.

• Helps reduce oil seepage and compression loss after a top-end job when installed correctly.

• Perfect for workshops handling pre-UCE Bullet rebuilds and regular decoke jobs.

• Pairs well with 144040 full engine gasket set when both top and bottom end are being rebuilt.

Compatibility Table

Core engine type: 346cc cast-iron Bullet (separate iron barrel + crankcases, distributor / points or CDI, pre-UCE).

CHECK PART NUMBER BEFORE PURCHASE 

Variants

• This listing:

  • Part Number: 144039

  • Description: Decoke / Top-End Gasket Kit – CAF Material – 350cc Cast-Iron Bullet

  • Contents: Top-end gasket set for de-carbonising / head work (exact contents per latest OE packing)

• Related (for cross-sell, separate SKUs):

  • 144040 – Full Engine Gasket Set (CAF) for CI Bullet / Electra / Lightning – when doing complete rebuilds.

FAQs

Q1. What’s the difference between 144039 and 144040?
A: 144039 is a decoke / top-end gasket kit for 350cc CI Bullets – used mainly when removing the cylinder head and doing valve / piston work. 144040 is a complete engine gasket set covering crankcases, chaincase etc. for full overhauls.

Q2. Will 144039 fit my Bullet 350 UCE or Classic 350 Reborn?
A: No. 144039 is only for older cast-iron Bullets (separate iron barrel). UCE and J-Series bikes use totally different alloy cylinders and gasket layouts with other part numbers.

Q3. Can I use this kit on a Bullet 500 or Lightning 535?
A: 

Q4. What jobs is this kit ideal for?
A: Use 144039 when you are:

• De-carbonising the head and piston

• Lapping valves / replacing valve stem seals

• Checking or replacing piston rings on a CI 350
  Any time the head and rocker box come off, a fresh decoke gasket set is recommended.

Q5. Do I still need sealant with this kit?
A: Follow the workshop manual – generally, a thin smear of appropriate sealant is used only on certain joints (if specified). Over-use of sealant can squeeze into oil passages, so rely on the gasket faces themselves for most joints.