Motorcycle Cylinder Head Base Seal For DT200R 3ET 1988-1991 Fit For Yamaha DT200R 3ET 1988-1991 66.75mm +75 oversize cylinder bore overhaul assembly Aligns engine mounting hole layout for direct installation without or extra conversion fittings oversized piston rings fit 66.75mm bore to seal combustion chamber reduce power loss Multi-layer cylinder base gasket blocks oil leakage during offroad trail riding All components follow upgraded oversize dimension specs to match cylinder rebuilding needs