Valve Adjustment Kit | Honda CB360 / CB550
Pull the valve covers on a fifty-year-old Honda and the adjusters are often chewed up, seized, or gone altogether. We have seen bikes missing every adjuster and lock nut in the head and still running. These are new replacements, sold as an adjuster screw and its lock nut together.
Why You Need This
The adjuster screw is what sets the gap between the rocker arm and the valve stem, and the lock nut is what keeps that setting where you put it. A rounded slot or a stripped thread means you cannot hold a setting, and a valve that drifts is the one that costs you. Too tight is what does damage; too loose only makes noise.
You set these every 1,500 miles (2,400 km) as part of our standard tune-up, in the order of cam chain first, then valves, then ignition timing.
Specifications
| Spec | Detail |
|---|
| Replaces OEM Parts | 90012-426-000, 90012-300-000, 90206-250-000 |
| Fits Models | CB360G/T (1974–1976), CL360 (1974–1975), CJ360T (1976–1977), CB500K (1971–1973), CB550K (1974–1978), CB550F (1975–1977) |
| Sold As | Sold Individually — one adjuster screw with its lock nut |
How many you need: a CB360 twin has four adjusters, two per cylinder. A CB500K or CB550 four has eight. Each unit here is one adjuster screw with its lock nut, so order the quantity your engine takes.
Valve Clearance Specs
Both engine families run the same numbers, set cold.
The exhaust side runs looser on purpose. Exhaust gas puts more heat into that side, so the metal expands further once the engine is hot.
Installation
Difficulty: Intermediate
Tools needed: flathead screwdriver, feeler gauge, offset box wrench (10mm on the CB360)
- Start cold. Pull the valve covers to reach the adjusters.
- Bring the cylinder you are working on to the top of its compression stroke. A finger over the spark plug hole will tell you — you will feel the air push out.
- On the CB360, line the rotor up on the LT mark for the left cylinder, then rotate 180 degrees to the T mark for the right. On the CB500K and CB550, set half the valves at number one TDC, then rotate one full turn for the rest.
- Back off the lock nut. The adjuster is a slotted screw, so a flathead holds it while you work.
- Set the gap with the feeler gauge, then tighten the lock nut while holding the screwdriver still. If the screw turns as the nut goes tight, the setting is gone.
The trick we use: go one gauge size up and set it snug rather than trying to feel a perfect slip fit. A 0.003 in. blade on an intake and a 0.004 in. blade on an exhaust, tightened until the gauge just drags, lands the clearance where it should be. Chasing an exact feel is how valves end up too tight.
An offset box wrench earns its place here. A straight wrench fights the surrounding castings; the offset gets on the nut and still leaves you room for the screwdriver and the feeler gauge at the same time.
The video walks the full adjustment on a CB360 twin. For the four-cylinder version of the same job, see our cam chain and valve adjustment guide for the CB500K / CB550.
Frequently Asked Questions
How many do I need to order?
Four for a CB360, CL360 or CJ360 twin. Eight for a CB500K, CB550K or CB550F four. Each unit is one adjuster screw with its lock nut, so a full set means ordering that many.
Does this fit my CB500K?
Yes. The product name is shorthand for the four-cylinder family, and the CB500K is covered along with the CB550K and CB550F.
What clearance should I set?
0.05 mm (0.002 in.) on the intake and 0.08 mm (0.003 in.) on the exhaust, with the engine cold. That is the same on the twins and the fours.
Will the CT90 / CB175 / CB200 valve adjustment wrench work on these?
No. That wrench is made for the square-head adjusters on the small bikes. These use a slotted screw with a separate hex lock nut, so you want a flathead screwdriver and an offset box wrench instead.
My valves are too tight after adjusting. What went wrong?
Usually the adjuster screw turned while the lock nut was being tightened. Hold the screwdriver still as you snug the nut. Setting by feel alone is the other common cause, which is why we set with one gauge size up.
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Last updated: August 2026
