Fork Seals (Standard) | Honda CB350 / CL350 / SL350
Fork seals are the last step of any front-end rebuild on a vintage CB350, CL350, or SL350. If the old seals are weeping oil onto your brake disc, the fork rebuild is not done. These are standard-style OEM replacement seals for the full CB350 family — but Honda changed fork architecture partway through the CB350 run, so you need to pick the right size for your bike.
Why You Need This
A leaking fork seal puts oil on your brake disc, drops fork oil level until the damping disappears, and fills the dust boot with an oily mess that ruins chrome. If the seal is leaking, you need to replace it. This is not a "ride it another season" problem.
These standard-style seals are direct OEM-style replacements. They install with the normal Honda fork rebuild procedure and need a seal driver (or a short section of pipe sized correctly) to press in evenly. If you want an easier install without a seal driver, our EZ Install fork seals are a better fit for the same bikes.
Specifications
| Spec | Detail |
|---|
| Replaces OEM Part Numbers | 91255-286-003, 91255-312-003, 91255-413-881 |
| Fits Models | CB350 K1–K5, CB350G, CL350 K1–K5 Scrambler, SL350 K0–K1 |
| Fork Tube Diameter | 33 mm |
| Sold As | Pair (one set per bike) |
Important: Pick the Right Size for Your Fork Architecture
Honda used two different fork architectures on the CB350 family. You must order the size that matches your bike:
- #8059 (33 mm x 44 mm) — Early style: Fits motorcycles with external spring forks. Use for CB350 K1–K3, CL350 K1–K3, and SL350 K0.
- #8000 (33 mm x 46 mm) — Late style: Fits motorcycles with internal spring forks. Use for CB350 K4–K5, CB350G, CL350 K4–K5, and SL350 K1. The #8000 seal also fits all CB360 / CL360 / CJ360 and the CB450 K0 Black Bomber.
If you are not sure which fork architecture is on your bike, read our fork architecture identification guide before ordering. The external-spring forks have a visible coil spring wrapped around the outside of the fork tube. The internal-spring forks hide the spring inside the fork body.
Model-Specific Notes
- SL350 K2: Uses larger 35 mm forks with a different seal. Order our 35 mm fork seals instead.
- SL350 K0 vs K1 outer diameter: Note that the SL350 K0 seal has a 44 mm outer diameter (uses the early-style #8059), and the SL350 K1 has a 46 mm outer diameter (uses the late-style #8000). Double-check your year before ordering.
Installation
Difficulty: Intermediate — fork rebuild procedure, standard seal driver required.
Installation tip: Lubricate the seals well with fork oil during installation. A short piece of pipe or a large socket sized to the outer diameter of the seal works as a driver and helps press the seal evenly into the lower fork tube without cocking it or tearing the lip.
For full step-by-step fork rebuild procedures matched to your bike's fork architecture, see our rebuild guides:
Frequently Asked Questions
How do I know which size I need?
Check your fork architecture. If you can see a coil spring wrapped around the outside of the fork tube, you have external-spring forks and need the #8059 (33 mm x 44 mm). If the spring is hidden inside the fork body, you have internal-spring forks and need the #8000 (33 mm x 46 mm). The safest way to confirm is to look up your bike in our fork architecture guide before ordering.
Will these fit my CB360 or CJ360?
Yes — specifically the #8000 (33 mm x 46 mm) late-style seals. The CB360, CL360, CJ360, and CB450 K0 Black Bomber all use the same 33 x 46 mm seal.
What about my SL350?
The SL350 K0 uses the #8059 (33 x 44), the SL350 K1 uses the #8000 (33 x 46), and the SL350 K2 uses a completely different 35 mm fork with different seals. Double-check your year.
The #8059 seals are too small for my forks — what do I order?
You have internal-spring forks (the later architecture). Order the #8000 (33 mm x 46 mm) instead. This is the most common first-time mistake on these seals.
Do I need any other parts while I am in here?
Replace the dust boots, check the fork oil level, and consider upgrading the loose-ball steering bearings at the same time — the whole front end is already apart. See the cross-sell list below.
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Last updated: April 2026
