Royal Enfield 140297/C Joint Rubber / Outer Chaincase Rubber Seal – Bullet 350/500 (Cast Iron/AVL) – Genuine Type

If your Royal Enfield is leaking oil/grease from the outer chaincase joint, the most common culprit is a hardened or flattened joint rubber. Part No. 140297/C is the correct joint rubber / rubber seal used at the outer chaincase joint on Royal Enfield Bullet models (older platform—Cast Iron / AVL era), restoring proper sealing and reducing messy leaks on the left side of the engine/chaincase area.

This is a small but critical sealing part: once it compresses with age, you’ll see seepage after rides, chaincase contamination, and repeated “cleaning + leak” cycles. Replacing the joint rubber during chaincase service, clutch work, or leak rectification is the right fix—cheap part, big improvement.

✅ Verified fitment is listed below. If you’re unsure about your exact year/engine platform, match your part number or share your VIN/model photo before ordering to avoid returns.

Sources confirm the item as 140297/C – JOINT RUBBER and describe it as a rubber seal / outer chaincase joint rubber for Bullet applications.

Key Features 

• Genuine-type joint rubber for outer chaincase sealing

• Helps prevent oil/grease seepage from chaincase joint area

• Direct replacement for Part No. 140297/C

• Ideal during chaincase opening / clutch inspection / leak repair

• Restores proper compression seal vs. old flattened rubber

• Improves cleanliness around left engine/chaincase side

• Lightweight, easy to store as a preventive spare

Compatibility

Confirmed by 2 independent sources (PASS)

• Royal Enfield Bullet (Cast Iron / AVL era) – “fits Bullet” + Bullet model family references

Not confirmed enough to publish as “fits” (FAIL – shown by only 1 source, so we are NOT claiming fitment)

Some catalogs list additional models, but they are single-source only and not published here to avoid wrong orders.

Return-prevention note (must read):
This part number commonly appears on older Bullet/AVL-type parts catalogs. It is NOT verified for UCE / J-Series engines by two independent sources, so do not buy for UCE “Classic 350/500 UCE / GT 535 UCE” unless your old part number matches 140297/C.

Variants

• Single option: 140297/C (1 pc)

What’s in the Box

• 1 × Joint Rubber (Outer Chaincase Joint Seal) – Part No. 140297/C

Installation Notes

• Replace while the chaincase is open; clean joint surfaces before refit.

• If seepage continues, inspect mating surface flatness and related gaskets/seals.

• If your bike is UCE/J-Series: verify part number first.

FAQs 

Q1. What is 140297/C used for?
It’s a joint rubber / rubber seal used at the outer chaincase joint to prevent seepage.

Q2. Will it fit Classic 350 UCE / Classic 500 UCE / GT 535 UCE?
Not confirmed by two independent sources. Buy only if your old part number matches 140297/C.

Q3. Symptoms of a bad joint rubber?
Grease/oil seepage from chaincase joint, persistent wetness on left side, messy chaincase area.

Q4. Is this a gasket?
It’s a rubber seal/joint rubber, not a paper gasket.