Royal Enfield 1570401 / 1570401/B – Piston Ring (2nd Compression Ring) for J-Series 350 – Classic Reborn, Meteor, Hunter, Bullet 350 – Genuine OEM

The Royal Enfield 1570401 / 1570401/B – RING-PISTON (2ND) is the genuine second compression ring used in the new J-Series 350 engine family – Classic 350 Reborn, Meteor 350, Hunter 350 and Bullet 350 (BS6). Official dealer portals (Bike-Parts-RoyalEnfield, OEM export price lists) list 1570401/B as “RING-PISTON (2ND)” and classify it with the 350 piston & cylinder group. 

The dedicated Meteor 350 piston & cylinder parts page clearly shows 1570401/B as “RING-PISTON (2ND)” in the same assembly as cylinder KLJ00018.

The 2nd ring works with the top (1st) ring and oil ring to seal compression, control blow-by and support oil control. If your bike has low compression, smoking, hard starting or increased oil consumption, a worn 2nd ring is often part of the problem. Replacing it with a genuine OEM ring ensures the correct profile, tension and end-gap for the J-Series 350 bore – something cheap local rings often get wrong.

For best results, this ring should usually be installed along with the 1st ring (1570400/B) and oil ring (1570402/B) as a full set, after honing/inspection by a trained mechanic.

Key Features

• Genuine Royal Enfield piston ring – part no. 1570401 / 1570401/B – RING-PISTON (2ND), as per official RE parts lists and dealer catalogues. 

• Designed specifically for the J-Series 350 engine used in Meteor 350, Classic 350 Reborn, Hunter 350, Bullet 350 BS6.

• Acts as the second compression ring, improving sealing and helping reduce blow-by and oil consumption.

• Manufactured to OEM tolerances for diameter, ring tension and end-gap, matching the factory-fitted ring. 

• Compatible with the OE cylinder & piston assembly KLJ00018 used on J-Series 350 models. 

• Ideal for top-end overhauls, decarbonising jobs and rebuilds after high mileage or poor lubrication.

• Helps restore lost compression, throttle response and fuel efficiency when used with a proper hone and fresh oil.

• Genuine part means correct material & coating, avoiding premature wear common with non-OEM rings.

Compatibility Table (Confirmed – No Guesswork)

PLEASE CHECK PART NUMBER BEFORE PURCHASE  

Variants / Related Parts 

These are separate SKUs – not bundled variants of 1570401 – but you can cross-link as “Complete Ring Set”:

• 1570400/B – RING-PISTON (1ST) – Top compression ring for J-Series 350. 

• 1570401/B – RING-PISTON (2ND) – This product (second compression ring).

• 1570402/B – RING-PISTON (OIL) – 3-piece oil control ring for J-Series 350. 

FAQs

Q1. Which bikes use piston ring 1570401 / 1570401/B?
This ring is used as the 2nd compression ring in the J-Series 350 engine, fitted to Meteor 350, Classic 350 Reborn (All New Classic 350), Hunter 350 and the new Bullet 350 (BS6). This mapping is backed by the Meteor 350 piston & cylinder parts list and multiple OEM ring-set listings for these four models.

Q2. Should I change only the 2nd piston ring or the full set?
Technically you can replace just the 2nd ring if only that ring is damaged, but in real-world engine work it’s strongly recommended to replace the full set (1st + 2nd + oil ring) and check piston-to-bore clearance. That gives better sealing, balanced wear and longer life.

Q3. Is 1570401 an original Royal Enfield part?
Yes. Bike-Parts-RoyalEnfield and other official distributors list 1570401/A & 1570401/B as RING-PISTON (2ND) and clearly mark them as certified Royal Enfield genuine parts, not aftermarket copies. 

Q4. Will this fit my older Classic 350 UCE or Bullet 350 UCE?
No – this ring is catalogued for J-Series 350 only. Older UCE / Cast-Iron 350 engines use different piston and ring dimensions. Using the wrong ring set can cause rapid wear, poor compression or even engine damage, so always match by model + engine type + part number.

Q5. Do I need any special tools to fit this ring?
Your mechanic should use basic engine tools like a ring expander, feeler gauges and (ideally) a ring compressor, plus a bore gauge/micrometer to measure wear. Proper honing, end-gap checking and torque-to-spec reassembly are essential for a long-lasting rebuild.