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1985 Honda CB450SC Nighthawk Valve & Guide Parts Planning

For cylinder-head work on a 1985 CB450SC Nighthawk, identify the intake and exhaust positions before counting replacement parts. The available valves have different references and required counts. Guide-clip design and intake stem-seal specification also need confirmation when the head contains replacement components.

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Honda CB400 CB450 exhaust valve 14721-413-000

Honda CB400 / CB450 Exhaust Valve ~ Replaces 14721-413-000

$19.95 USD
01-9962
Restore proper engine performance with this Exhaust Valve, designed as a direct replacement for the original Honda component. This valve replaces OEM part number...
Honda CB750 CB450 CB400 CB360 CB77 valve guide clip 12211-250-310

Honda CB Valve Guide Clip ~ Replaces 12211-250-310

$1.95 USD
73-0939
Replace your valve guide clip with this Valve Guide Clip, replacing OEM #12211-250-310.Sold each, order the quantity you require.Key Features• Valve guide clip• Replaces...
New
Honda CB400 CB450 intake valve 14711-235-010

Honda CB400 / CB450 Intake Valve ~ Replaces 14711-235-010

$19.95 USD
01-9961
Restore proper engine performance with this Intake Valve, designed as a direct replacement for the original Honda component. This valve replaces OEM part number...
Honda CB400 CB450 CB125 valve stem seal 12208-413-003

Honda CB400 / CB450 / CB125 Valve Stem Seal

$3.10 USD
01-0128
Stop top-end oil loss with this Valve Stem Seal, a replacement for OEM #12208-413-003 / #12209-KL4-005 / #12209-428-003. Fits a range of smaller-displacement Hondas,...
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1985 Honda CB450SC Nighthawk · Valvetrain Buying guide

Count the affected positions after checking the head

The listed head uses four intake valves and two exhaust valves for a complete replacement. Each valve is sold separately. The 12208-413-003 seals cover the four intake positions; the two exhaust valves require a different seal specification. A guide with an integral shoulder may not use the separate retaining clip.

Parts to consider

Honda CB400 / CB450 Intake Valve ~ Replaces 14711-235-010 Individual intake valveOne intake valve replaces 14711-235-010. The listed engine has two intake valves per cylinder, so a complete intake-valve replacement requires four.View part Honda CB400 / CB450 Exhaust Valve ~ Replaces 14721-413-000 Individual exhaust valveOne exhaust valve replaces 14721-413-000. One is required per cylinder, giving two for the complete engine; keep it separate from the intake-valve order.View part Honda CB400 / CB450 / CB125 Valve Stem Seal Stem seal for an intake positionEach 12208-413-003 intake seal is supplied individually and matches the three listed intake-seal references. Four are used on the listed CB450 twin; the exhaust specification is different.View part

Related parts: Verify the replacement guide’s clip design

Let measurements establish the valve order

The valve information calls for guide-clearance, seat-condition, spring-condition and installed-height checks during head work. A new valve does not correct a worn guide or a damaged seat. Have the condition assessed with the Honda procedure before ordering replacements for every position solely because the head is apart.

Check the guide maker’s retention design

The separate clip suits a compatible stock-style guide. Some performance guides have a machined retaining shoulder and must not receive an additional clip. Match the replacement guide instructions before ordering clips, and retain the required checks for guide protrusion, interference fit, stem clearance and seat alignment.

Valvetrain purchase questions

How many valves and intake seals should I order for a complete replacement?

Order four individual intake valves and two individual exhaust valves for the listed engine. The 12208-413-003 seal is supplied each for the four intake positions. The two exhaust valves use a different seal specification, so do not order six of this seal.

Should I buy guide clips before choosing replacement valve guides?

Establish the replacement guide design first. The 12211-250-310 clip fits a compatible stock-style guide, but some performance guides use an integral shoulder and prohibit a separate clip. Follow that guide manufacturer’s instructions when deciding whether clips belong in the order.

Can I complete the repair by ordering valves and seals without assessing the guides?

Assess the guide clearances and valve-seat condition before finalizing the parts list. Worn guides or damaged seats remain a problem with new valves, and excessive stem-to-guide clearance can still draw oil past new seals. Use the Honda-specified head checks to establish the required work.

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