Oil at a cover joint calls for a different part from a worn shaft seal. For your 1981 Honda CB650, identify the leaking position before ordering, then match the gasket outline or seal dimensions to the assembly actually fitted.
1969 Honda CB750K Motorcycle Parts1970 Honda CB750K Motorcycle Parts1971 Honda CB500K Four Motorcycle Parts1971 Honda CB750K Motorcycle Parts1972 Honda CB500K Four Motorcycle Parts1972 Honda CB750K Motorcycle Parts1973 Honda CB125S0 Motorcycle Parts1973 Honda CB500K Four Motorcycle Parts1973 Honda CB750K Motorcycle Parts1974 Honda CB125S1 Motorcycle Parts1974 Honda CB550K Motorcycle Parts1974 Honda CB750K Motorcycle Parts1975 Honda CB125S2 Motorcycle Parts1975 Honda CB550F Supersport Motorcycle Parts1975 Honda CB550K Motorcycle Parts1975 Honda CB750F Motorcycle Parts1975 Honda CB750K Motorcycle Parts1976 Honda CB125S3 Motorcycle Parts1976 Honda CB550F Supersport Motorcycle Parts1976 Honda CB550K Motorcycle Parts1976 Honda CB750A Motorcycle Parts1976 Honda CB750F Motorcycle Parts1976 Honda CB750K Motorcycle Parts1977 Honda CB550F Supersport Motorcycle Parts1977 Honda CB550K Motorcycle Parts1977 Honda CB750A Motorcycle Parts1977 Honda CB750F Motorcycle Parts1977 Honda CB750K Motorcycle Parts1978 Honda CB550K Motorcycle Parts1978 Honda CB750A Motorcycle Parts1978 Honda CB750F Motorcycle Parts1978 Honda CB750K Motorcycle Parts1979 Honda CB650 Motorcycle Parts1980 Honda CB650 Motorcycle Parts1980 Honda CB650C Custom Motorcycle Parts1981 Honda CB650 Motorcycle Parts1981 Honda CB650C Custom Motorcycle Parts1982 Honda CB650 Motorcycle Parts1982 Honda CB650SC Nighthawk Motorcycle PartsHonda CB Engine Gaskets, Oil Seals & HardwareHonda CB Engine PartsHonda CB125 Motorcycle Parts by Model & YearHonda CB125S Motorcycle Parts (1973–1985)Honda CB500 Motorcycle Parts by Model & YearHonda CB500K Motorcycle Parts (1971–1973)Honda CB550 Motorcycle Parts by Model & YearHonda CB550F Motorcycle Parts (1975–1977)Honda CB550K Motorcycle Parts (1974–1978)Honda CB650 Motorcycle Parts (1979–1982)Honda CB650 Motorcycle Parts by Model & YearHonda CB650C Custom Motorcycle Parts (1980–1981)Honda CB650SC Nighthawk Motorcycle Parts (1982–1985)Honda CB750 Motorcycle Parts by Model & YearHonda CB750 SOHC Parts (1969–1978)Honda CB750A Hondamatic Motorcycle Parts (1976–1978)Honda CB750F Motorcycle Parts (1975–1982)Honda CB750K Motorcycle Parts (1969–1982)Series 10: CB72-CB250 (59-85)Series 5: CB650 (79-82)Series 6: CB500-CB550 (71-78)
Replace your cylinder sleeve O-rings with this Cylinder Sleeve O-Ring Set of 4, replacing OEM #91304-286-000.Key Features• Cylinder sleeve O-rings, 4 per set• Replaces...
Replace your CB650 cylinder head gasket with this Cylinder Head Gasket, replacing OEM #12251-426-306.Key Features• Cylinder head gasket• Replaces OEM #12251-426-306Fitment / Compatibility• All...
Rebuild your CB650 engine with this Athena Overhaul Engine Gasket Set. Athena of Italy is an original-equipment supplier to Yamaha, Honda, Kawasaki, Suzuki, and...
1971 Honda CB500K Four Motorcycle Parts1972 Honda CB500K Four Motorcycle Parts1973 Honda CB500K Four Motorcycle Parts1974 Honda CB550K Motorcycle Parts1975 Honda CB550F Supersport Motorcycle Parts1975 Honda CB550K Motorcycle Parts1976 Honda CB550F Supersport Motorcycle Parts1976 Honda CB550K Motorcycle Parts1977 Honda CB550F Supersport Motorcycle Parts1977 Honda CB550K Motorcycle Parts1978 Honda CB550K Motorcycle Parts1979 Honda CB650 Motorcycle Parts1980 Honda CB650 Motorcycle Parts1980 Honda CB650C Custom Motorcycle Parts1981 Honda CB650 Motorcycle Parts1981 Honda CB650C Custom Motorcycle Parts1982 Honda CB650 Motorcycle Parts1982 Honda CB650SC Nighthawk Motorcycle PartsHonda CB Engine Gaskets, Oil Seals & HardwareHonda CB Engine PartsHonda CB500 Motorcycle Parts by Model & YearHonda CB500K Motorcycle Parts (1971–1973)Honda CB550 Motorcycle Parts by Model & YearHonda CB550F Motorcycle Parts (1975–1977)Honda CB550K Motorcycle Parts (1974–1978)Honda CB650 Motorcycle Parts (1979–1982)Honda CB650 Motorcycle Parts by Model & YearHonda CB650C Custom Motorcycle Parts (1980–1981)Honda CB650SC Nighthawk Motorcycle Parts (1982–1985)Series 5: CB650 (79-82)Series 6: CB500-CB550 (71-78)
Replace your CB650 or CB500/CB550 cylinder base gasket with this Cylinder Base Gasket, replacing OEM #12191-426-306.Key Features• Cylinder base gasket• Replaces OEM #12191-426-306Fitment /...
Individual head, base and cover gaskets allow a focused repair. Shaft seals need their own size and reference checks; a general engine-gasket label does not establish every component in a set.
The head gasket seals a different joint from the cylinder-base and valve-cover gaskets. Inspect the engine before ordering so that a small cover repair does not become a mismatched top-end purchase. Keep the correct reference with each position on your parts list.
Size shaft seals individually
The selected shift-shaft seal is 12.5 × 25 × 8 mm. Other shafts use different seals, so retain the old markings and identify the location. Confirm unlisted kit contents with the store before relying on a set for several seal positions.
Ordering questions
Is the valve-cover gasket the same as the head gasket?
No. They seal different joints. Choose the valve-cover gasket for its cover position and the cylinder-head gasket for a head repair; identify where the engine is leaking before buying.
Can I choose a shaft seal from outside diameter alone?
Use all of the specified dimensions and the correct shaft position. For the selected shift-shaft seal, compare 12.5 × 25 × 8 mm and reference 91204-425-003 with the fitted assembly.
What should I check before buying an overhaul gasket set?
Compare the documented contents with your dismantling plan. Do not assume that every shaft oil seal, fastener or cover component is included simply because the package is called an overhaul set.
Not sure which part you need?
Send your model and year, plus photos of your existing part and any changes to the original setup.