Genuine Royal Enfield Piston Ring Set +0.040" O/S (3 Rings) for Bullet 350 / Electra 4S–5S / Machismo / Campus | 112054

For a proper 350cc top-end rebuild after a rebore, you must match ring size to the new bore. Royal Enfield Part No. 112054 is listed as “PISTON RING SET .040"”, meaning +0.040 inch oversize (O/S)—not STD. 

This ring set is commonly supplied as a set of 3 rings and is intended for legacy 350cc Bullet-family engines (confirmed models below).  Correct oversize rings help restore compression, cold starting, throttle response, and oil control, while reducing smoke caused by worn rings/cylinder wear.

Do not order this unless your cylinder is actually rebored to 0.040” O/S (verify with bore measurement or machinist bill). Using the wrong size is one of the biggest causes of repeat smoke, low compression, and premature wear. Dealer listings also show multiple oversize options in this family, so keep your listing strict and clearly labeled as 0.040 O/S to reduce returns. 

Key Features 

• Genuine Royal Enfield piston ring set (OEM-spec) 

• Part Number: 112054

• Official description: PISTON RING SET .040" (+0.040" oversize) 

• Commonly supplied as set of 3 piston rings 

• Designed for legacy 350cc Bullet-family platforms (confirmed below) 

• Helps reduce blue smoke/oil burning and improves compression after rebore

• Better dimensional consistency vs many generic aftermarket ring sets

• Recommended: check ring end-gap and cylinder honing finish before assembly

Compatibility Table 

Explicit exclusions (avoid wrong orders): UCE (Classic/Bullet/Thunderbird UCE), J-Series (Classic Reborn/Hunter/Meteor/Bullet J), 650 Twins, Himalayan/Scram—unless you have microfiche/VIN proof for your exact platform.

Variants

• Only one variant here: +0.040" O/S – 112054 
  (Keep STD and other oversizes as separate SKUs/listings to prevent returns.)

FAQs 

Q1. What does “.040" / +0.040 O/S” mean?
It means the cylinder is rebored 0.040 inch oversize, and these rings are sized for that bore—not STD. 

Q2. How many rings are included?
Dealer descriptions commonly specify a set of 3 piston rings for this 350cc oversize set. 

Q3. Will 112054 fit Classic 350 UCE or Classic 350 Reborn (J-Series)?
Not confirmed. This part number is documented for legacy Bullet/Electra/Machismo/Campus 350 family applications only. 

Q4. My bike is smoking—should I buy +0.040 rings?
Only if the cylinder is already rebored to +0.040”. If your bore is STD or +0.020, you must use the correct ring size. 

Q5. What else should be replaced during installation?
Top-end gasket set, verify piston condition, hone cylinder, and measure ring end-gap before final assembly.