Engine Sprocket 25T (Primary Drive) for Royal Enfield Bullet / Electra (Legacy) | 110221/12 | Genuine

Royal Enfield 110221/12 is the Engine Sprocket (Primary Drive) used on select legacy Bullet/Electra-era Royal Enfield models. It is commonly referred to as the 25-tooth (25T) engine sprocket, and is also seen as an update/replacement reference for older 110221 numbering in some catalogs. 

If your bike has issues like primary chain noise, worn sprocket teeth, or inconsistent power transfer to the clutch basket/primary drive, replacing the engine sprocket during a primary chain service can restore smoothness and reduce premature chain wear.

OEM vs aftermarket: Aftermarket sprockets often vary in tooth profile accuracy and heat-treatment consistency. An OE-spec sprocket helps maintain correct primary chain engagement and long-term durability—especially important on older Bullets where primary drive health directly affects refinement and reliability.

Important fitment note (to reduce returns): Different Bullet/Electra generations (AVL/CI/Lean-burn/EFi/UCE) can use different primary components. Buy only if your parts manual/microfiche maps your bike to 110221/12.

Key Features 

• Genuine Royal Enfield spare: 110221/12 – ENGINE SPROCKET 

• Commonly sold/identified as Engine Sprocket 25 Teeth (25T) 

• Reference mapping seen in the market: 110221/12 (old ref: 110221) 

• Designed for correct primary drive chain engagement when matched to the right model

• Ideal during primary chain replacement, clutch service, or engine overhaul

• Helps reduce chain slap/noise caused by hooked/worn sprocket teeth

• Quantity: 1 piece per bike (engine sprocket) 

Compatibility Table 

PLEASE CHECK PART NUMBER BEFORE PURCHASE

Variants

• Single unit (1 pc) — 110221/12 only
  (No LH/RH, no color variants for sprocket)

FAQs 

1) Is 110221/12 the same as 110221?
Some sellers reference 110221/12 as replacement for old 110221—always match by parts manual for your bike. 

2) How many teeth does this sprocket have?
Commonly sold/identified as 25T for this part reference. 

3) Will it fit Classic 350 Reborn / Meteor / Hunter / Interceptor 650?
No—those are different platforms. Order only if your microfiche shows 110221/12.

4) What symptoms indicate replacement?
Primary chain noise, hooked sprocket teeth, excessive slack fluctuation, or rough power transfer.

5) Should I change the primary chain too?
Recommended to inspect and replace chain/tensioner pad if worn—new sprocket + old stretched chain can wear quickly.