VintageCB750 Supplying CB Riders Since 2010

About Us Why Us? Reviews Shipping Info Returns Contact Us
Wish Lists
0 My Cart

Your cart is currently empty.

Browse all parts
Total (USD): $0.00
View cart
Menu
Search
Wish
Cart 0
My motorcycle Choose your Honda CB model

Search parts

Searching all Honda CB parts

Example: brake pads or oil filter.

1981 Honda CB900C Custom Engine Gaskets & Seals

Begin gasket selection on a 1981 CB900C Custom with the exact joint or shaft that needs attention. A valve-cover leak, shift-shaft seal and top-end rebuild use different components. Check any larger package first so individual seals are not duplicated unnecessarily.

Close ×
Your saved bike Choose your Honda CB model

Shop By Category

Most orders ship same or next business day Fitment guarantee Listed for your exact model and year? We’ll make it right if it doesn’t fit as described. Mechanic-backed support Ask our team for help choosing the right Honda CB part.
Currently viewing Gaskets & Oil Seals & Engine Hardware

Honda motorcycle parts

Choose your model and year to see parts listed for your bike.

Honda CB1100 CB1000 CB900 CB750 alternator cover gasket 11691-425-000

Honda CB1100 / CB1000 / CB900 / CB750 Alternator Cover Gasket ~ Replaces 11691-425-000

$12.64 USD
12-5008
Replace the alternator cover gasket on your DOHC CB with this Alternator Cover Gasket, replacing OEM #11691-425-000. Fits the 1979-82 CB750 family, CB750SC Nighthawk,...
Honda CB1100 CB1000 CB900 CB750 valve cover gasket 12391-425-010

Honda CB1100 / CB1000 / CB900 / CB750 Valve Cover Gasket ~ Replaces 12391-425-010

$32.95 USD
12-1002
Replace your DOHC CB's valve cover gasket with this Valve Cover Gasket, replacing OEM #12391-425-010. Fits the 1979-82 CB750 family, CB750SC Nighthawk, CB900 family,...
Sold out
Honda CB1100 CB1000 CB900 CB750 left crankcase cover gasket 11395-425-306

Honda CB1100 / CB1000 / CB900 / CB750 Left Crankcase Cover Gasket ~ Replaces 11395-425-306

$14.95 USD
18-7055
Replace your DOHC CB's left crankcase (generator) cover gasket with this Generator Cover Gasket, replacing OEM #11395-425-306.Key Features• Left crankcase / generator cover gasket•...
Honda CB1100 CB1000 CB900 CB750 oil pan gasket 11398-425-306

Honda CB1100 / CB1000 / CB900 / CB750 Oil Pan Gasket ~ Replaces 11398-425-306

$15.94 USD
18-7053
Replace your DOHC CB's oil pan gasket with this Oil Pan Gasket, replacing OEM #11398-425-306. Broad fitment across the CB750A Hondamatic, full 1979-82 CB750...
Sold out
Honda CB1100 CB1000 CB900 exhaust headpipe gasket (each) 18291-MM5-860

Honda CB Exhaust Headpipe Gasket (Each) ~ Replaces 18291-MM5-860

$6.84 USD
18-7013
Replace one cylinder-head-to-exhaust-headpipe gasket on your big-bore Honda with this Cylinder Head to Exhaust Headpipe Gasket, 1 piece, replacing OEM #18291-MM5-860. Exceptionally broad fitment...
Honda CB1100 CB1000 CB900 CB750 clutch cover gasket 11396-425-306

Honda CB1100 / CB1000 / CB900 / CB750 Clutch Cover Gasket ~ Replaces 11396-425-306

$22.95 USD
12-5042
Rebuild your DOHC CB's clutch cover with this Clutch Cover Gasket, replacing OEM #11396-425-306. Fits the 1979-82 CB750 family, CB750SC Nighthawk, CB900 family, CB1000C,...
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 CB900 CB750 spark advancer cover gasket 30372-425-000

Honda CB1100 / CB1000 / CB900 / CB750 Spark Advancer Cover Gasket ~ Replaces 30372-425-000

$7.95 USD
18-7059
Replace your DOHC CB's spark advancer cover gasket with this Spark Advancer Cover Gasket (rubber O-ring), replacing OEM #30372-425-000.Key Features• Spark advancer cover gasket...
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 CB1100 CB1000 CB900 CB750 DOHC screw set

Honda CB1100 / CB1000 / CB900 / CB750 DOHC Screw Set

$39.95 USD
73-0099
Refresh DOHC carb hardware top to bottom with this 71-Piece DOHC Screw Set. Includes front stay plate screws (8), CV cap screws (8), throttle...
Honda CB750 CB900 CB1000C engine oil seal kit made in japan with 6 seals 91256-425-003

1979-83 Honda CB750 / CB900 / CB1000C Engine Oil Seal Kit

$44.95 USD
01-9034
Seal up your DOHC-era CB's engine rebuild with this 6-piece Engine Oil Seal Kit. Superior OEM quality, made in Japan, and built for the...
Honda CB1100 CB1000 CB900 CB750 camshaft holder seal 91311-425-000

Honda CB1100 / CB1000 / CB900 / CB750 Camshaft Holder Seal ~ Replaces 91311-425-000

$5.50 USD
18-7066
Replace your DOHC CB's camshaft holder seal with this Camshaft Holder Rubber Seal (triangular piece with rounded corners), replacing OEM #91311-425-000. One piece required...
Sold out
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...
Sold out
Honda CB900 CB750 cylinder head gasket Athena premium quality 12251-438-023

1979-82 Honda CB900 / CB750 Cylinder Head Gasket ~ Athena Premium Quality ~ Replaces 12251-438-023

$74.95 USD
18-7000
Replace your DOHC CB's cylinder head gasket with this Athena Premium Quality Cylinder Head Gasket, replacing OEM #12251-438-023.Key Features• Athena premium cylinder head gasket•...
Honda CB1100 CB1000 CB900 CB750 countershaft oil seal 40 x 62 x 13.5 91205-425-003

Honda CB1100 / CB1000 / CB900 / CB750 Countershaft Oil Seal ~ 40 x 62 x 13.5 ~ Replaces 91205-425-003

$14.95 USD
73-0969
Replace your countershaft oil seal with this Countershaft Oil Seal, 40 x 62 x 13.5, replacing OEM #91205-425-003. High-quality, made in Japan.Key Features• Countershaft...
Honda CB1100 CB1000 CB900 CB750 starter motor cover gasket 31282-425-300

Honda CB1100 / CB1000 / CB900 / CB750 Starter Motor Cover Gasket ~ Replaces Honda OEM 31282-425-300

$11.69 USD
18-7070
Starter Motor Cover Gasket ~ Replaces Honda OEM 31282-425-300 for the Honda CB models listed below. Use this part for repair, restoration, or replacement...
Honda CB900 CB750 cylinder base gasket Athena premium quality 12191-425-306

1979-83 Honda CB900 / CB750 Cylinder Base Gasket ~ Athena Premium Quality ~ Replaces 12191-425-306

$22.18 USD
18-6991
Replace your DOHC CB's cylinder base gasket with this Athena Premium Quality Cylinder Base Gasket, replacing OEM #12191-425-306.Key Features• Athena premium cylinder base gasket•...
Honda CB1100 CB1000 CB900 CB750 crankshaft seal 25 x 42 x 8 91201-425-003

Honda CB1100 / CB1000 / CB900 / CB750 Crankshaft Seal ~ 25 x 42 x 8 ~ Replaces 91201-425-003

$10.50 USD
73-0966
Replace your crankshaft seal with this Crankshaft Seal, 25 x 42 x 8, replacing OEM #91201-425-003. High-quality, made in Japan.Key Features• Crankshaft Seal• 25...
New
Honda CB900C CB900F overhaul gasket set

1980-82 Honda CB900C / CB900F Overhaul Gasket Set

$114.95 USD
18-0099
Rebuild your CB900C Custom or CB900F Supersport engine with this Engine Overhaul Gasket Set.Key Features• Engine overhaul gasket setFitment / Compatibility• Honda CB900C (1980‑82)...
Sold out
Honda CB900C CB900F Athena gasket set (top end set only)

1980-82 Honda CB900C / CB900F Athena Gasket Set (Top End Set Only)

$169.95 USD
18-0433
Freshen up the top end of your CB900C or CB900F with this Athena Top End Gasket Set. Athena of Italy is an original-equipment supplier...
Honda CB1100 CB1000 CB900 CB750 oil pump shaft seal 25 x 47 x 10 91257-425-013

Honda CB1100 / CB1000 / CB900 / CB750 Oil Pump Shaft Seal ~ 25 x 47 x 10 ~ Replaces 91257-425-013

$13.95 USD
73-0967
Replace your oil pump shaft seal with this Oil Pump Shaft Seal, 25 x 47 x 10, replacing OEM #91257-425-013. High-quality, made in Japan.Key...
Honda CB900C CB900F Athena overhaul gasket set

1980-82 Honda CB900C / CB900F Athena Overhaul Gasket Set

$229.00 USD
18-0116
Rebuild your CB900C or CB900F engine with this Athena Overhaul Gasket Set. Athena of Italy is an original-equipment supplier to Yamaha, Honda, Kawasaki, Suzuki,...
Honda CB900 CB750 cylinder base gasket 12191-425-306

1979-83 Honda CB900 / CB750 Cylinder Base Gasket ~ Replaces Honda OEM 12191-425-306

$16.38 USD
18-7052
Cylinder Base Gasket ~ Replaces Honda OEM 12191-425-306 for the Honda CB models listed below. Use this part for repair, restoration, or replacement work...
Honda CB900 CB750 cylinder head gasket 12251-438-023

1979-82 Honda CB900 / CB750 Cylinder Head Gasket ~ Replaces Honda OEM 12251-438-023

$54.95 USD
18-7051
Cylinder Head Gasket ~ Replaces Honda OEM 12251-438-023 for the Honda CB models listed below. Use this part for repair, restoration, or replacement work...
Sold out
Honda CB900 CB750 cylinder sleeve o-ring gasket 91302-425-000

1979-83 Honda CB900 / CB750 Cylinder Sleeve O-Ring Gasket ~ Replaces 91302-425-000

$4.61 USD
18-7067
Replace your DOHC CB's cylinder sleeve O-rings with this Cylinder Sleeve O-Rings Set of 4, replacing OEM #91302-425-000. Four pieces required per engine.Key Features•...
compare

1981 Honda CB900C Custom · Engine Gaskets & Seals Buying guide

Separate a local oil leak from a top-end rebuild

On the 1981 Custom, an oil trace at the head cover and a leak around the shift shaft call for different inspections. Locate the first wet point before choosing a gasket package. The separate dual-range gearbox also makes the precise leaking joint important.

Parts to consider

Honda CB1100 / CB1000 / CB900 / CB750 Valve Cover Gasket ~ Replaces 12391-425-010 Valve-cover gasketReplacement for the DOHC valve cover, reference 12391-425-010.View part Honda CB Shift Shaft Oil Seal ~ 12.5 x 25 x 8 ~ Replaces 91204-425-003 Shift-shaft sealJapanese-made 12.5 × 25 × 8 oil seal; reference 91204-425-003.View part 1980-82 Honda CB900C / CB900F Athena Gasket Set (Top End Set Only) Athena top-end gasket setHead, base and valve-cover gaskets, four headpipe gaskets, camshaft-holder seal, four sleeve O-rings and additional O-rings.View part

Related parts: Four sleeve O-rings

A head-cover repair is different from head removal

The head-cover gasket is disturbed for valve-clearance service. Honda specifies checking it for damage and applying sealant only at the locations shown in the cover procedure. Removing the cylinder head or block is a larger, engine-out job with head, base and other seals to account for; the top-end set does not promise every engine oil seal.

Match shaft seals to the damaged location

The shift-shaft seal is listed as 12.5 × 25 × 8mm. Check that exact position and the shaft’s sealing surface before fitting a replacement. A new seal cannot correct a damaged shaft or a distorted cover. Keep cylinder-sleeve O-rings separate from valve-stem seals and account for any pieces already included in a gasket set.

Buying questions

Should the whole valve-cover gasket be coated in sealant?

Follow Honda’s head-cover diagram. It identifies particular sealing points rather than a full coating. Inspect the gasket and cover first; extra sealant or excessive tightening is not a repair for damaged rubber or a distorted sealing face.

Does a leak near the shift lever call for a top-end gasket set?

First trace the oil to its source. If it starts at the shift shaft, inspect that shaft and its individual seal. A head or base gasket set serves different joints and will not repair a shaft-seal leak.

How do I decide between separate gaskets and the top-end set?

List every joint the planned work will open and compare the itemized contents. The Athena set includes head, base and head-cover gaskets, exhaust gaskets and selected seals. Buy separate parts for uncovered joints or a limited repair, without duplicating included sleeve O-rings.

Not sure which part you need?

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

Ask a fitment question
Parts categories for 1981 Honda CB900C

Your cart

×