Hero Xtreme 125R Cylinder Kit | Genuine Block Piston Bore Kit | K12121ACLA000S

Hero Xtreme 125R Cylinder Kit – K12121ACLA000S

Rebuild a worn or damaged engine cylinder section with the Hero Genuine Cylinder Kit K12121ACLA000S. This exact Hero kit is best supported for the Hero Xtreme 125R / Xtreme 125 engine application where this part number is confirmed through the Hero EPC, original packet, VIN record, or existing component.

This product is commonly searched as Xtreme 125R cylinder kit, Hero Xtreme 125 block piston kit, Xtreme 125R bore kit, Hero 125cc cylinder piston kit, engine block piston assembly, cylinder standard kit, and K12121ACLA000S.

What This Product Is

• Hero Genuine engine cylinder kit
• Product description: CYLINDER KIT
• Part number / MPN: K12121ACLA000S
• Common market name: Cylinder kit / block piston kit / bore kit
• Application area: Engine cylinder and piston section
• Best-supported model family: Hero Xtreme 125R / Xtreme 125

Key Features

• Genuine Hero MotoCorp engine-rebuild kit
• Exact replacement where K12121ACLA000S is specified
• Suitable for diagnosed cylinder wear, compression loss, piston or cylinder damage, excessive engine smoke, oil consumption, or piston slap
• Helps restore compression and combustion when the remaining engine components are serviceable
• Exact-SKU selection offers better fitment accuracy than choosing a generic 125cc bore kit only by engine capacity
• Current exact-SKU seller price reference: ₹3,350

S.No	Part No	Description	Qty	Part Image
1	12100-AAN-B00	CYLINDER COMP.	1
2	12191-AAN-B0099	GASKET, CYLINDER	1
3	12251-AAN-B01	GASKET, CYLINDER HEAD	1
4	12391-AAN-B01	GASKET, HEAD COVER	1
5	13111-AAN-B00	PIN, PISTON	1
6	13101-AAN-B0099	PISTON	1
7	13115-001-000	CLIP, PISTON PIN	2
8	ACLAE0E001000G	RING SET PISTON STD	1

Confirmed / Best-Supported Compatibility

• Hero Xtreme 125R / Xtreme 125 where K12121ACLA000S is specified in the Hero EPC or on the original packet

Hero Xtreme 125R OBD-II catalogues show the corresponding 125cc engine cylinder and cylinder-head assembly family, but the exact kit number should still be verified for the motorcycle's manufacturing month and variant before ordering.

Compatibility Not Automatically Claimed

• Hero Glamour or Glamour XTEC
• Hero Super Splendor
• Hero Xtreme 160R
• Hero Xtreme 200R / Xtreme 200S
• Hero Hunk or Ignitor export variants
• Any other Hero 125cc motorcycle without direct part-number confirmation

Fitment Note / Return Prevention Note

Before ordering, match K12121ACLA000S with the old packet, existing kit, Hero EPC, or VIN record. Also verify:

• Motorcycle model and manufacturing year
• Standard or OBD-II generation
• Engine family and engine number
• Existing cylinder and piston specification
• Oil-passage and mounting design
• Gasket arrangement

Do not order only by engine capacity or visual similarity. Hero uses multiple cylinder-kit revisions across its 125cc motorcycle range.

Similar Part Numbers – Do Not Mix

• K12121AANNB01S
• K12121AANNB02S
• K12121ACRA001S
• K12121ACKA000S
• Other K12121-series Hero cylinder kits

The suffix is significant. Similar-looking kits can differ by cylinder design, piston specification, engine revision, emission generation, gasket combination, or model application.

Kit Contents

This product is identified as a CYLINDER KIT. A reliable public exact-SKU bill of materials for K12121ACLA000S is not available. Only the components physically supplied inside the sealed Hero package should be represented as included.

Do not automatically promise the piston, piston rings, piston pin, clips, cylinder gasket, or cylinder-head gasket until the actual sealed package has been checked.

What You Will Receive

• 1 × Hero Genuine Cylinder Kit
• Part number: K12121ACLA000S
• Only the components physically included inside the sealed Hero package
• Cylinder head, valves, camshaft, crankshaft, connecting rod, timing-chain components, engine oil, labour, and unrelated overhaul parts are not included unless physically packed and explicitly stated

Technical Details

Installation Note

Professional engine installation is strongly recommended. Before assembly, inspect the cylinder head, valves, connecting rod, crankshaft play, oil pump, cam chain, guides, tensioner, cylinder studs, mating surfaces, and lubrication system. Confirm piston orientation, ring end gaps, timing marks, tightening sequence, torque values, and valve clearance before starting the engine.

Buyer-Focused FAQs

Q1. What is Hero part number K12121ACLA000S?
It is a Hero Genuine Cylinder Kit, commonly called a block piston kit or bore kit.

Q2. Is this for Hero Xtreme 125R?
The strongest researched application is Hero Xtreme 125R / Xtreme 125. Confirm the exact SKU through the Hero EPC, VIN, old packet, or existing kit before ordering.

Q3. Does it fit every Xtreme 125R?
Do not rely only on the model name. Confirm the manufacturing year, OBD generation, and exact part number because engine-part revisions can occur.

Q4. Does it fit Glamour or Super Splendor?
No such compatibility is being claimed for this SKU. Those models use other cylinder-kit part numbers in several applications.

Q5. Are the piston, rings, pin, clips, and gaskets included?
The exact public kit BOM is unavailable. Check the sealed Hero package before promising individual components.

Q6. Is this a performance big-bore kit?
No. It is a genuine replacement cylinder kit, not a capacity-increase or racing kit.

Q7. Should a mechanic install it?
Yes. Cylinder-kit replacement requires precision measurements, engine timing, lubrication, torque control, and post-assembly checks.