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1981 Honda CB650C Custom Gaskets & Engine Seals

A gasket order for the 1981 CB650C Custom should follow the engine joints you plan to disturb. The cylinder-cover gasket, sleeve O-rings and shift-shaft seal have separate locations and package details. Compare the old parts before adding a larger sealing kit.

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Currently viewing Gaskets & Oil Seals & Engine Hardware

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Honda CB1100 CB1000 shift shaft oil seal 12.5 x 25 x 8 91204-425-003

Honda CB Shift Shaft Oil Seal ~ 12.5 x 25 x 8 ~ Replaces 91204-425-003

$4.61 USD
73-0968
Replace your shift shaft oil seal with this Shift Shaft Oil Seal, 12.5 x 25 x 8, replacing OEM #91204-425-003. High-quality, made in Japan.Key...
Honda CB1100 CB1000 tach drive oil seal 4.8 x 14.5 x 5 91256-425-003

Honda CB Tach Drive Oil Seal ~ 4.8 x 14.5 x 5 ~ Replaces 91256-425-003

$4.95 USD
73-0964
Replace your tach drive oil seal with this Tach Drive Oil Seal, 4.8 x 14.5 x 5, replacing OEM #91256-425-003. High-quality, made in Japan.Key...
Honda CB750 CB550 CB650 cylinder head nut cover 91318-300-013

Honda CB750 / CB550 / CB650 Cylinder Head Nut Cover

$3.74 USD
01-0137
Restore the clean look of your cylinder head with this Rubber Cylinder Head Nut Cover, a replacement for OEM Ref. #91318-300-013. Fits all 1969-78...
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Honda CB750 CB900 CB650 cam cover seal 90541-425-000

Honda CB750 / CB900 / CB650 Cam Cover Seal

$11.95 USD
01-0116
Keep oil where it belongs with this Cam Cover Seal, a direct replacement for OEM #90541-425-000. Fits a wide range of late-'70s through early-'80s...
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Honda CB650 CB650C CB650SC valve cover gasket 12391-460-770

1979-82 Honda CB650 / CB650C / CB650SC Valve Cover Gasket ~ Replaces 12391-460-770

$23.05 USD
18-6995
Replace your CB650 valve cover gasket with this Valve Cover Gasket (cylinder cover), replacing OEM #12391-460-770.Key Features• Valve cover (cylinder cover) gasket• Replaces OEM...
Honda CB750 CB650 cylinder sleeve o-ring gasket set 91304-286-000

Honda CB Cylinder Sleeve O-Ring Gasket Set ~ Replaces 91304-286-000

$4.50 USD
18-7068
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...
Honda CB650 CB650C CB650SC alternator cover gasket 11691-426-306

1979-82 Honda CB650 / CB650C / CB650SC Alternator Cover Gasket ~ Replaces 11691-426-306

$11.05 USD
18-6994
Replace your CB650 alternator cover gasket with this Alternator Cover Gasket, replacing OEM #11691-426-306.Key Features• Alternator cover gasket• Replaces OEM #11691-426-306• Honda part name:...
Honda CB750 CB650 CB550 CB500 crank seal 30 x 42 x 8 91201-300-003

Honda CB Crank Seal ~ 30 x 42 x 8 ~ Replaces 91201-300-003

$7.00 USD
73-0960
Replace your crank seal with this Crank Seal, 30 x 42 x 8, replacing OEM #91201-300-003. High-quality, made in Japan.Note: please reference the OEM...
Honda CB650 engine oil seal kit made in japan

1980-82 Honda CB650 Engine Oil Seal Kit

$34.95 USD
01-9003
Rebuild your CB650 with this 7-piece Engine Oil Seal Kit, built to superior OEM quality and made in Japan. A complete seal bundle for...
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Honda CB650 CB650C CB650SC cylinder head gasket 12251-426-306

1979-82 Honda CB650 / CB650C / CB650SC Cylinder Head Gasket ~ Replaces 12251-426-306

$59.95 USD
18-6992
Replace your CB650 cylinder head gasket with this Cylinder Head Gasket, replacing OEM #12251-426-306.Key Features• Cylinder head gasket• Replaces OEM #12251-426-306• Honda part name:...
Honda CB650 CB650C CB650SC overhaul gasket set

1979-82 Honda CB650 / CB650C / CB650SC Overhaul Gasket Set

$139.95 USD
18-0440
Rebuild your CB650 engine with this Overhaul Engine Gasket Set.Key Features• Overhaul engine gasket setFitment / Compatibility• Honda CB650 (1979‑82)• CB650C (1980‑81) Custom• CB650SC...
Honda CB650 CB650C CB650SC Athena overhaul gasket set

1979-82 Honda CB650 / CB650C / CB650SC Athena Overhaul Gasket Set

$179.95 USD
18-0202
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...
Honda CB650 CB550 CB500 cylinder base gasket 12191-426-306

Honda CB650 / CB550 / CB500 Cylinder Base Gasket ~ Replaces 12191-426-306

$18.50 USD
18-6993
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 #12191-426-306• Honda...
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Honda CB650 CB650C CB650SC Athena gasket set (top end set only)

1979-82 Honda CB650 / CB650C / CB650SC Athena Gasket Set (Top End Set Only)

$149.95 USD
18-0434
Freshen up the top end of your CB650 with this Athena Top End Gasket Set. Athena of Italy is an original-equipment supplier to Yamaha,...
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1981 Honda CB650C Custom · Gaskets & Engine Seals Buying guide

Match the sealing shape and position together

A cover gasket, four sleeve O-rings and a dimensioned shaft seal are distinct service choices. Their shared model application does not make their materials, profiles or installation locations interchangeable.

Parts to consider

1979-82 Honda CB650 / CB650C / CB650SC Valve Cover Gasket ~ Replaces 12391-460-770 Valve cover gasketCylinder-cover gasket for the CB650 engine; replaces Honda reference 12391-460-770.View part Honda CB Cylinder Sleeve O-Ring Gasket Set ~ Replaces 91304-286-000 Cylinder sleeve O-ring setFour cylinder sleeve O-rings replacing reference 91304-286-000.View part Honda CB Shift Shaft Oil Seal ~ 12.5 x 25 x 8 ~ Replaces 91204-425-003 Shift-shaft oil seal12.5 × 25 × 8 seal replacing reference 91204-425-003.View part

Use position-specific replacements

The cylinder cover uses reference 12391-460-770; the sleeve O-ring set uses 91304-286-000. Keep those references tied to their actual positions. Inspect mating surfaces and related components using the service manual before deciding which sealing parts to renew.

Check broader sets against the teardown

The seven-piece oil seal kit and the available overhaul gasket sets serve wider repair scopes. Their package names do not provide every detail of the planned job. Compare confirmed contents with the opened joints so individual parts are neither missed nor duplicated.

Gaskets & Engine Seals questions

What should be inspected before replacing a leaking shift-shaft seal?

Check for shaft play, wear grooves, crankcase pressure or a blocked breather, and correct any problem before fitting the new seal. A correctly sized replacement still needs a sound shaft and the cause of the leak addressed.

How do I match the shift-shaft seal before ordering?

The selected seal is specified at 12.5 × 25 × 8 and replaces 91204-425-003. Compare the shaft position, old seal and reference before choosing the replacement for the actual engine.

What if the engine has been replaced?

Identify the fitted engine and the particular cover or shaft position before choosing parts. The frame’s 1981 Custom identity cannot verify every component of a replacement engine.

Not sure which part you need?

Send your model and year, plus photos of your existing part and any changes to the original setup.

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