Hero Genuine 33K112S 0.50 (2nd Oversize) Piston & Ring Kit for CD100 SS / 100 SS – Piston, Rings, Pin & Clips

Hero Genuine 33K112S 0.50 Second Oversize Piston & Ring Kit for CD100 SS / 100 SS

Hero 33K112S is the genuine II-Over Size / 0.50 mm oversize piston and ring kit for the older Hero / Hero Honda CD100 SS, later referred to as 100 SS application supported by current specialist fitment references.

This is not a standard-size piston kit. It is intended for an engine whose cylinder has been correctly measured and machined / bored for the second oversize (+0.50 mm) specification. Order this kit only after the bore size has been confirmed by the mechanic or machine shop.

Quick Product Details

Confirmed Compatibility

Do not broaden this fitment to every Hero 100 cc motorcycle. Hero's current e-shop page describes 33K112S generically as a 100 cc application, but independent model-specific references consistently map this exact part number to CD100 SS / 100 SS. This listing therefore stays conservative.

What Does “0.50 / Second Oversize” Mean?

A piston is not chosen only by motorcycle model. During an engine rebuild, the cylinder bore must be measured. If the cylinder has worn beyond the standard-size service limit, a machine shop may rebore / hone it to an approved oversize.

33K112S is the +0.50 mm second-oversize kit. It should be used only when the cylinder bore has been prepared for that exact size.

If the cylinder is still standard size, or has only been bored to +0.25 mm, this kit is incorrect even if the motorcycle is a CD100 SS.

Hero Size Cross-Reference – Do Not Order the Wrong Piston

Important: Do Not Confuse 33K112S with 33K122S

Hero also lists 33K122S as a separate II-Over Size (Y2K) piston-ring kit for Splendor+. That is a different Hero part number.

33K112S is not being sold here as a Splendor+ piston kit. If you have a Splendor / Splendor+ or another 100 cc Hero model, match the exact engine application and Hero part number before ordering.

What Comes in the Kit?

Hero's current product page describes 33K112S as a complete piston-ring-set replacement package and lists:

• Piston
• Piston ring set
• Piston pin / gudgeon pin
• Retaining clip(s)

Hero also describes the package as a multi-component / five-part kit. This listing therefore treats 33K112S as a complete piston-and-ring service kit, not as loose piston rings only.

Why Would a Buyer Need This Kit?

This part is normally considered during an engine top-end rebuild after the cylinder and piston have been inspected and measured.

Common reasons a mechanic may recommend piston / ring and bore work include:

• Low compression
• Excessive engine-oil consumption
• Blue exhaust smoke caused by worn piston / ring / bore condition
• Poor cylinder sealing
• Loss of engine performance linked to compression wear
• Piston or ring damage
• Excessive cylinder wear requiring reboring
• Top-end overhaul after seizure or scoring

These symptoms do not automatically prove that 0.50 mm oversize is required. The cylinder must be measured before ordering.

Why Bore Measurement Comes Before Buying

Oversize piston kits are precision engine-rebuild parts. The correct sequence is:

1. Open and inspect the engine.
2. Measure the cylinder bore and wear / taper / scoring.
3. Determine whether the cylinder remains standard or requires reboring.
4. Confirm the required oversize: Standard, +0.25 mm, +0.50 mm, etc.
5. Order the matching piston kit.
6. Machine / finish the bore to the piston manufacturer's required clearance and workshop specification.

Do not buy a +0.50 piston kit first and assume it will fit an untouched standard cylinder.

Buyer Search Names for 33K112S

Workshops and owners may search this same product using different terms, including:

• CD100 SS piston kit 0.50
• CD100 0.50 piston
• Hero Honda CD100 SS second oversize piston
• CD100 piston ring kit 0.50
• CD100 2nd oversize piston kit
• 100 SS piston kit
• Hero 33K112S
• 33K112S piston set
• 33K112S piston ring kit

Why Choose Hero Genuine for an Engine Rebuild?

Piston-to-cylinder clearance, ring fit, pin fit and component dimensions are critical during an engine rebuild. Using the exact Hero part number helps the mechanic work from the intended specification rather than relying on a visually similar aftermarket kit.

Correct part selection still does not replace proper cylinder measurement and machining.

Fitment / Return Prevention

Before ordering, confirm all of the following:

• Motorcycle is the supported CD100 SS / 100 SS application
• Exact Hero part number required is 33K112S
• Cylinder requires +0.50 mm / II-Over Size
• Mechanic / machine shop has measured the bore
• You are not actually looking for 33K110S Standard or 33K111S +0.25
• You are not looking for the separate 33K122S Y2K / Splendor+ application

For old engines with previous rebuild history, the safest check is the part number + existing piston marking + measured bore.

Installation Note

Professional engine rebuilding / machining is strongly recommended. A second-oversize piston kit must be matched to the correctly prepared cylinder bore and installed with the correct piston-to-bore clearance, ring orientation, ring end gap, piston-pin installation and engine assembly procedure.

• Measure the bore before machining.
• Confirm piston size before final honing.
• Check ring end gaps according to service specifications.
• Install rings in the correct orientation.
• Use the correct piston direction / marking.
• Install retaining clips securely.
• Use new gaskets / seals where the engine service requires them.
• Follow correct tightening torque and engine-break-in procedure after rebuild.

What You Will Receive

1 × Hero Genuine 33K112S II-Over Size 0.50 Piston & Ring Kit

Hero's product description lists piston, piston ring(s), pin and clip(s) as the included replacement components.

Buyer-Focused FAQs

What is Hero 33K112S?
It is Hero's genuine II-Over Size / +0.50 mm piston and ring kit for the supported 100 SS / CD100 SS application.

Does 33K112S fit Hero Honda CD100 SS?
Yes, current specialist fitment references specifically map 33K112S to CD100 SS / 100 SS. It is correct only when the engine requires the +0.50 mm second-oversize piston.

Is 33K112S a standard-size piston?
No. 33K112S is +0.50 mm second oversize.

Which Hero part number is standard size?
Hero lists 33K110S as the Standard piston ring / piston kit for the related 100 cc series.

Which part number is +0.25 mm first oversize?
Hero lists 33K111S as the +0.25 mm I-Over Size kit.

What does “II-Over Size” mean?
It means second oversize. For 33K112S, Hero specifies 0.50 mm oversize.

Can I install 33K112S in a standard cylinder?
No. The cylinder must be measured and correctly prepared for the +0.50 mm piston size.

Does 33K112S fit Splendor Plus?
This listing does not claim Splendor+ fitment. Hero separately lists 33K122S as the II-Over Size Y2K kit for Splendor+.

Does it fit every Hero 100 cc motorcycle?
No. Although Hero's current shop page describes it generically as a 100 cc kit, the model-specific references checked map 33K112S to CD100 SS / 100 SS. Do not generalise by engine capacity alone.

Does the kit include the piston or only rings?
Hero's current product page lists piston, piston ring(s), pin and clip(s), so this is a complete piston-service kit rather than loose rings only.

What is the current Hero MRP?
Hero's current official e-shop lists ₹685 inclusive of taxes.

Should I order 0.50 just because the engine is smoking?
No. Smoke can have multiple causes. The cylinder and piston must be inspected and measured before choosing an oversize.