About This

• 📏 Bore Size Verification - DT125 top end kit includes a 56.00mm bore cylinder (standard size). Before ordering this cylinder piston kit for Yamaha, verify your original cylinder uses 56mm bore. The 123cc displacement requires this exact 56mm piston size. Not for DT125 bored to 57mm or 58mm oversize - measure your existing cylinder before purchase.
• 📆 Year Compatibility Check - This top end rebuild kit fits for Yamaha DT125 models from 1974 through 1981. Compatible with DT125A (1974), DT125B (1975), DT125C (1976), DT125D (1977), DT125E (1978), DT125F (1979), DT125G (1980), and DT125H (1981). The 56mm cylinder kit restores compression on all these DT125 dual-purpose models.
• 🔧 Complete Kit Contents - DT125 engine rebuild kit includes everything for a full top end overhaul: 56mm cylinder, standard size piston, piston ring set (2 rings), wrist pin, 2 circlips, cylinder head gasket, and cylinder base gasket. The 123cc top end kit contains all components needed for Yamaha DT125.
• ⚠️ Signs Your DT125 Needs Kit - For Yamaha DT125 blows blue smoke from the exhaust, the piston rings are worn. Loss of compression (below 100 psi) or hard starting when cold indicates worn 56mm cylinder bore. Excessive piston slap noise (metallic rattling when cold) points to worn piston or cylinder. This DT125 top end kit restores compression and eliminates oil burning on your 1974-1981 for Yamaha. Replace before piston seizure damages the connecting rod.
• 🛠️ Professional Installation Required - DT125 cylinder piston kit requires mechanical experience. The 56mm cylinder must be checked for proper ring gap before installation. Ring end gap specification for Yamaha DT125 is 0.15-0.35mm (0.006-0.014 inches). Piston height is 65.00mm - verify deck clearance. Torque cylinder head nuts to factory specification (18-22 ft-lbs / 24-30 Nm). Incorrect installation causes compression loss or engine seizure.