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1978 Honda CB400A Exhaust Parts

An exhaust leak at the cylinder head needs a different seal from a headpipe joint or crossover connection. Locate the affected joint on your CB400A before ordering. A separate slip-in muffler option is available for an exhaust retaining the appropriate inlet arrangement.

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Honda CB900 CB650 CB550 exhaust headpipe gasket (each) 18212-634-000

Honda CB Exhaust Headpipe Gasket (Each) ~ Replaces 18212-634-000

$3.58 USD
17-2813
Replace one exhaust port gasket on your CB650, CB400, CB450, or modern CB900F with this Exhaust Port Gasket, 1 piece, replacing OEM #18212-634-000 /...
Honda CB900 CB650 CB550 exhaust headpipe gaskets (pk 10) 18212-634-000

Honda CB Exhaust Headpipe Gaskets ~ (Pk/10) ~ Replaces 18212-634-000

$27.95 USD
17-3813
Stock up on exhaust port gaskets for your CB650, CB400, CB450, or modern CB900F with this 10-pack, replacing OEM #18212-634-000 / #18291-236-000 / #18291-MN4-920.Key...
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Honda CB450 CB400 exhaust joint gasket for headpipe 18391-413-000

1978-86 Honda CB450 / CB400 Exhaust Joint Gasket for Headpipe ~ Replaces 18391-413-000

$10.73 USD
17-4504
Replace your CB400 or CB450 exhaust joint gasket with this Exhaust Joint Gasket for Headpipe, replacing OEM #18391-413-000 / #18391-413-010.Key Features• Exhaust joint gasket...
Honda CB750 CB650 CB550 CB450 exhaust crossover gasket 18392-413-000

Honda CB Exhaust Crossover Gasket ~ Replaces 18392-413-000

$9.95 USD
17-4505
Replace your Nighthawk or CB400/CB450 exhaust crossover gasket with this Exhaust Crossover Gasket, replacing OEM #18392-413-000 / #18392-MG7-750. Fits the mid-'80s CB750SC/CB650SC/CB550SC Nighthawks plus...
Chrome slip in style muffler 23 7 8" long for Honda CB motorcycles

Chrome Slip In Style Muffler ~ 23 7/8" Long

$139.95 USD
07-0020
Chrome Slip In Honda Style Muffler ~ 23 7/8" Long with 4" Diameter. Fits to bikes that use a slip in inlet such as...
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1978 Honda CB400A · Exhaust Buying guide

Order the seal for the joint you are opening

Three gasket choices address different exhaust connections. Individual port gaskets and a ten-pack provide quantity choices, while the linked slip-in muffler requires its own inlet and mounting checks. Follow the fitted system rather than its overall appearance.

Parts to consider

Honda CB Exhaust Headpipe Gasket (Each) ~ Replaces 18212-634-000 Individual exhaust-port gasketOne gasket per order, referencing 18212-634-000, 18291-236-000 and 18291-MN4-920.View part 1978-86 Honda CB450 / CB400 Exhaust Joint Gasket for Headpipe ~ Replaces 18391-413-000 Headpipe joint gasketCB400A headpipe-joint application referencing 18391-413-000 and 18391-413-010.View part Honda CB Exhaust Crossover Gasket ~ Replaces 18392-413-000 Crossover joint gasketReplaces reference 18392-413-000 / 18392-MG7-750 at the specified exhaust connection.View part

Related parts: Exhaust-port gaskets, pack of ten · Individual chrome slip-in muffler

Separate port seals from sleeve-style joints

The individual port gasket serves the cylinder-head connection. The headpipe joint and crossover gaskets have their own references and positions. Identify the joint in the service documentation before ordering; a broadly matching CB400A application does not make these gasket shapes interchangeable.

Check the retained exhaust before choosing a muffler

The linked chrome muffler uses a slip-in inlet and comes with an adjustable slide bracket. It is sold individually for either side. Check the existing collector, inlet and mounting position, especially after previous exhaust modifications, before planning a one- or two-muffler order.

Exhaust questions

Should I buy individual port seals or a ten-pack?

Choose by the number of cylinder-head joints being opened and any spare seals you want to keep. The single-item option supplies one port gasket and the pack supplies ten. Headpipe and crossover seals are separate purchases.

Are the headpipe and crossover gaskets the same?

No. The headpipe joint gasket references 18391-413-000 / 18391-413-010; the crossover option references 18392-413-000 / 18392-MG7-750. Match the particular connection rather than choosing by the general exhaust category.

Can I use the linked muffler after an exhaust conversion?

Check the converted system’s inlet and mounting arrangement first. The muffler is designed for a slip-in connection. Its CB400A application does not establish fit on every aftermarket collector, headpipe or custom exhaust.

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