Genuine Royal Enfield 581736/C Blow Moulded Resonator Box (Intake Resonator / Airbox Resonator Chamber) – Bullet 350 UCE (KS/ES), Electra 350 UCE (ES), Classic 350

Royal Enfield 581736/C is the OEM Blow Moulded Resonator Box—also commonly searched as the intake resonator, airbox resonator chamber, or intake silencer box. It is a genuine Royal Enfield spare part, built to factory dimensions and intended to control intake resonance (reducing intake drone), while supporting stable airflow routing in the intake system. 

Replace this resonator box if your existing unit is cracked, deformed by heat, damaged during repairs, or causing loose-fit vibration/rattles near the side panel/airbox area. Many aftermarket “resonator boxes” are generic shells with inconsistent plastic quality and fitment—leading to air leaks, rubbing, or repeated mounting issues. This OEM part is listed as identical to the factory-fitted component when the vehicle was new.

Key Features 

• Genuine Royal Enfield part number 581736/C

• Official name: BLOW MOULDED RESONATOR BOX 

• Dealer-listed fitment for Bullet 350 UCE (KS/ES), Electra 350 UCE (ES), Classic 350 

• OE-grade moulding for correct fitment and mounting alignment (reduces jugaad clamps)

• Helps reduce intake resonance/harsh induction noise (resonator function)

• Ideal replacement for cracked/damaged resonator box to avoid rattles and misalignment

• Better reliability vs generic aftermarket plastic that can warp or fit poorly

• MRP/part existence is also reflected in distributor price lists (sanity check) 

Compatibility Table 

PLEASE CHECK PART NUMBER NEFORE PURCHASE 

❓ Not confirmed (do not list as compatible / verify by VIN before ordering)

• Classic 350 Reborn (J-Series)

• Bullet 350 J-Series

• Hunter 350 / Meteor 350 / Himalayan / Scram / 650 Twins
  (Several marketplace listings mention other models, but they are not treated as verified fitment sources.)

Variants

• No variants confirmed for this part number (single SKU: 581736/C). 

FAQs 

1) What is part number 581736/C?
It is the BLOW MOULDED RESONATOR BOX (intake resonator/airbox resonator chamber), genuine Royal Enfield. 

2) Which bikes does 581736/C fit?
Bullet 350 UCE (KS/ES), Electra 350 UCE (ES), Classic 350. 

3) Does this part improve performance?
It is primarily a factory intake resonance/control component. Replace it for correct fitment, reduced rattles, and proper intake routing—especially if the old box is cracked or loose.

4) Will it fit Classic 350 Reborn (J-Series)?
Not confirmed. Order only if your Royal Enfield parts catalog/VIN lookup matches 581736/C for your bike.

5) What should I check before ordering?
Confirm your bike is in the verified model set above and compare the old part/connector/mounting layout. If your mechanic has removed the resonator earlier, confirm the mounting points still exist.