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  • Honda CB Starter Motor Seal 24.4 x 3.1 ~ Replaces 91312-MG7-003
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Honda CB starter motor seal 24.4 x 3.1 91312-MG7-003
Corrected parts fiche reference for SKU 03-0780
Honda CB Starter Motor Seal 24.4 x 3.1 ~ Replaces 91312-MG7-003 — Front three-quarter
Honda CB Starter Motor Seal 24.4 x 3.1 ~ Replaces 91312-MG7-003 — Rear three-quarter
Honda CB Starter Motor Seal 24.4 x 3.1 ~ Replaces 91312-MG7-003 — Left side
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Honda CB starter motor seal 24.4 x 3.1 91312-MG7-003

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Load image into Gallery viewer, Honda CB starter motor seal 24.4 x 3.1 91312-MG7-003
Load image into Gallery viewer, Corrected parts fiche reference for SKU 03-0780
Load image into Gallery viewer, Honda CB Starter Motor Seal 24.4 x 3.1 ~ Replaces 91312-MG7-003 — Front three-quarter
Load image into Gallery viewer, Honda CB Starter Motor Seal 24.4 x 3.1 ~ Replaces 91312-MG7-003 — Rear three-quarter
Load image into Gallery viewer, Honda CB Starter Motor Seal 24.4 x 3.1 ~ Replaces 91312-MG7-003 — Left side
5.0 ( 1 review)

Honda CB Starter Motor Seal 24.4 x 3.1 ~ Replaces 91312-MG7-003

03-0780
$4.50 USD
In stock Usually ships the same or next business day
Check model fitment View fitment
Questions about this part? Contact us 4.8/5 1,347 store reviews
Secure checkoutProtected payment
60-day returnsEligible unused parts Free ground shippingUSA & Canada over $50
Browse all parts

1 product reviews

Honda CB Starter Motor Seal 24.4 x 3.1 ~ Replaces 91312-MG7-003

Honda CB Starter Motor Seal 24.4 x 3.1 ~ Replaces 91312-MG7-003
$4.50 USD
Description

Seal up your starter motor with this Starter Motor Seal, size 24.4 x 3.1, replacing OEM #91312-MG7-003 / #91309-300-000 / #91309-425-003. Exceptionally wide fitment across the classic Honda four-cylinder and twin lineup from the late '60s through the mid '80s. An essential service part whenever you're pulling the starter.

Key Features
• Replaces OEM #91312-MG7-003 / #91309-300-000 / #91309-425-003
• Size: 24.4 x 3.1
• Starter motor sealing
• Wide fitment across classic Honda lineup
• Honda part name: O-ring (24.4X3.1)

Fitment / Compatibility

• Honda CB750K (1969‑78)
• CB750F (1975‑78)
• CB750A (1976‑78)

• Honda CB750K (1979‑82)
• CB750L (1979)
• CB750F (1979‑82)
• CB750C (1980‑82)

• Honda CB750SC (1982‑83)

• Honda CB900C (1980‑82)

• Honda CB650 (1979‑82)
• CB650C (1980‑81)
• CB650SC (1982‑85)

• Honda CB500K (1971‑73)
• CB550K (1974‑78)
• CB550F (1975‑77)
• CB550SC (1983)

• Honda CB400A (1978)
• CB400TI (1978‑79)
• CB400T (1980‑81)
• CB450SC (1982‑83 / 1985‑86)
• CB450T (1982)

• Honda CB350F (1972‑74) Supersport
• CB400F (1975‑77) Supersport

Part Number: 03-0780

Read More
Read Less

Check the listed model and year, then read any fitment notes in the description.

Make Model Year
Honda CB750K Standard 1969
Honda CB750K 1970
Honda CB750K 1971
Honda CB750K 1972
Honda CB750K 1973
Honda CB750K 1974
Honda CB750K 1975
Honda CB750F Supersport 1975
Honda CB750K 1976
Honda CB750F 1976
Honda CB750A Hondamatic 1976
Honda CB750K 1977
Honda CB750F 1977
Honda CB750A 1977
Honda CB750K 1978
Honda CB750F 1978
Honda CB750A 1978
Honda CB750K Standard 1979
Honda CB750F Supersport 1979
Honda CB750L Limited 1979
Honda CB750K 1980
Honda CB750F 1980
Honda CB750C Custom 1980
Honda CB750K 1981
Honda CB750F 1981
Honda CB750C 1981
Honda CB750K 1982
Honda CB750F 1982
Honda CB750C 1982
Honda CB750SC Nighthawk 1982
Honda CB750SC 1983
Honda CB900C Custom 1980
Honda CB900C 1981
Honda CB900C 1982
Honda CB650 1979
Honda CB650 1980
Honda CB650 1981
Honda CB650 1982
Honda CB650SC Nighthawk 1982
Honda CB650C Custom 1980
Honda CB650C Custom 1981
Honda CB550K0 1974
Honda CB550K1 1975
Honda CB550K2 1976
Honda CB550K3 1977
Honda CB550K4 1978
Honda CB550F1 1975
Honda CB550F2 1976
Honda CB550F3 1977
Honda CB500K0 1971
Honda CB500K1 1972
Honda CB500K2 1973
Honda CB400F 1975
Honda CB400F 1976
Honda CB400F 1977
Honda CB350F0 1972
Honda CB350F0 1973
Honda CB350F1 1974
Honda CB650SCD Nighthawk 1983
Honda CB650SCE Nighthawk 1984
Honda CB650SCF Nighthawk 1985
Honda CB550SC Nighthawk 1983
Honda CB400A 1978
Honda CB400TII Hawk 1978
Honda CB400TIIZ Hawk 1979
Honda CB400TII Hawk 1978
Honda CB400TIIZ Hawk 1979
Honda CB400TA Hawk 1980
Honda CB400TB Hawk 1981
Honda CB450SCC Nighthawk 1982
Honda CB450SCD Nighthawk 1983
Honda CB450SCF Nighthawk 1985
Honda CB450SCG Nighthawk 1986
Honda CB450TC 1982

Free ground shipping over $50

To the USA & Canada. In-stock orders usually ship from our own warehouse the same or next business day.

Estimated ground delivery after your order ships
DestinationDelivery time
USA4–7 business days
Canada2–6 business days

Ground shipping includes tracking, emailed when your order ships. Need it sooner? Express options are available at checkout.

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60-day returns on eligible parts

No restocking fees. Eligible parts must be unused, uninstalled, unaltered and complete. The 60-day window starts when your order is delivered.

Electrical parts are excluded from standard returns. Check return eligibility.

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Other shipping options

Canada Post Economy: Available at checkout for select small items. Allow 1–3 weeks for delivery. No tracking or insurance is included.

Outside the USA & Canada: Delivery times vary by destination and shipping method. Buyers are responsible for applicable duties, taxes and import fees. We cannot mark orders as gifts.

Frequently Asked Questions

How many starter-motor seals are included and what size is 03-0780?

One 24.4 x 3.1mm starter-motor seal is included, enough to replace the single seal at one compatible starter-motor installation.

Which Honda OEM starter seal numbers does 03-0780 replace?

The seal replaces Honda OEM 91312-MG7-003, 91309-300-000 and 91309-425-003. Match one of those numbers and the listed model/year rather than choosing an O-ring by appearance alone.

Which Honda CB models use starter-motor seal 91312-MG7-003?

Listed fitment includes 1969-1982 CB750K, 1975-1982 CB750F, 1976-1978 CB750A, 1980-1982 CB750C, 1979 CB750L, 1982-1983 CB750SC, 1980-1982 CB900C, 1979-1982 CB650, 1980-1981 CB650C, 1982-1985 CB650SC, 1971-1973 CB500K, 1974-1978 CB550K, 1975-1977 CB550F, 1983 CB550SC, 1978 CB400A, 1978-1979 CB400TI, 1980-1981 CB400T, 1982 CB450T, 1982-1983 and 1985-1986 CB450SC, 1972-1974 CB350F and 1975-1977 CB400F.

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