Rebuilding the electric starter motor is straightforward if you slow down for details like brush orientation, alignment marks, proper grease packing, and endplay checks during assembly. This step-by-step rebuild video and guide covers:
Starter motor disassembly
Brush removal and replacement
Planetary gear service
Bushing replacement
Cleaning the commutator and brush plate
Reassembly, alignment, and armature end-play checks
Bench operation test
Compatibility
CB175 / CL175 / SL175
CB200 / CL200
CB350 / CL350 / SL350 K0
CB360 / CL360
CB450 / CL450 / CB500T
CB500K / CB550K / CB550F
CB750K / CB750F / CB750A
Note: While this starter motor rebuild procedure applies directly to the Honda CB350 and CB360 electric starter motors, and the same process can be used to rebuild the starters for the other vintage Honda motorcycles on this list.
Tools and supplies
Penetrating oil
Snap ring pliers
JIS / Phillips screwdriver
Heat gun
Plastic or rubber mallet
Picks / X-Acto knife
Fine steel wool
Isopropyl alcohol
Toothbrush (or small nylon brush)
Assorted sockets
Pliers
Wheel bearing grease
Anti-seize compound
Small bench vise (for bench test holding)
Small jumper cables (for bench test holding)
Small motorcycle battery (for bench test)
Parts included a typical starter motor rebuild kit
Our Common Motor Collective rebuild kits for these starters commonly include:
Brushes set (including one brush with a shielded lead)
O-rings
Oil/grease seal(s) for the planetary gear side
Bronze bushings (optional to install, but included in many kits)
Paper gaskets / shims (may be included, but may not be usable in every starter due to tolerance stack-up)
Sealed ball bearing (for CB450 / CL450 / CB500T rebuild kits)
Disassembly
Separate the starter
Soak the long threaded through-bolts with penetrating oil.
Remove the long through-bolts.
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Pull the starter apart into three main pieces:
Planetary gear side end cap (contains small gears and a large bearing)
Main housing
Brush/commutator side end cap (contains brushes and electrical components)
Remove brushes and armature
Identify the carbon brushes (the “small carbon cubes”) that ride on the commutator.
Pop the brushes out of their housings carefully.
Remove the small screw(s) securing brush leads to the brush mounting plate.
Important brush lead note
One brush has a shielded lead.
Mark which side this shielded brush attaches to before removal. The replacement brush in the kit must go back on the same side.
Tap the armature out of the main housing with light, controlled taps.
Set the armature aside for cleaning later.
Remove old gasket material
Scrape old gasket residue from mating surfaces.
Lightly clean the surface with very fine steel wool.
Do not remove unless necessary: Inside the housing are the field coil magnets. These are difficult to remove and are not required for the rebuild process shown. Leave them in place unless there is damage that truly requires removal.
Planetary gear side teardown (snap ring, seal, bearing, O-ring)
Mark one gear and its corresponding post (for example, with a paint marker) so the gear returns to the same location and orientation.
Slide off the two small planetary gears.
Flip the planetary housing and remove the snap ring using snap ring pliers.
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Support the housing on two small blocks of wood and tap the gearset out with a plastic/rubber mallet.
If stuck, heat the housing with a heat gun and try again.
Remove the oil/grease seal.
Remove the triangular metal clip beneath the seal (retains the bearing).
Drive out the bearing using a socket and light taps.
Peel off and discard the old O-ring from the planetary assembly.
Cleaning and inspection
Cleaning the electrical components
Clean electrical components using isopropyl alcohol and a toothbrush.
Lightly “deglaze” the commutator using super fine 0000 steel wool to remove the polished carbon glaze and refresh the contact surface.
Caution: Do not contaminate the commutator or brush contact surfaces with grease during reassembly.
Rebuild and reassembly
Reinstall planetary bearing and gears
Pack the bearing with wheel bearing grease on the open side if reusing the original.
Heat the planetary housing for about 5–10 minutes with a heat gun.
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Install the bearing with correct orientation:
Closed side facing out
Grease-packed/open side facing in
Note: If the rebuild kit comes with a replacement bearing, it will usually be a fully sealed bearing with no open sides. These new bearings come prepackaged with grease and can be installed in either direction.
Reinstall the triangular clip to retain the bearing.
Install the new oil seal.
Press/tap the rotating housing back into place with a mallet.
Verify the assembly rotates freely.
Reinstall the snap ring.
Pack the planetary gear cavity generously with wheel bearing grease (these are often found nearly dry).
Reinstall the gears:
Put the marked gear back on the marked post facing the same direction as when it was removed.
Replace bronze bushings (optional)
This is the hardest part of the job. The bushings are optional and should only be replaced if the originals are worn.
Removal setup (both bushings)
Soak bushings with penetrating oil.
Heat the plates/housing with a heat gun for 10–15 minutes.
Large bushing removal (plate side)
Support the plate on a larger socket as a stand.
Use a socket matching the bushing size to drive it out with light taps.
With enough heat, it should move with minimal force.
Small bushing removal (thin housing side)
Heat the housing and around the bushing for 10 minutes.
Very gently tap the entire housing on a piece of soft wood wood to attempt to knock the bearing out. Since this bushing is a blind bushing, we have found through testing for this to be the only reliable way to remove the bushing and not damage the housing.
Caution: This housing is thin and can crack. Do not rush this step. Use heat and time, not force.
Install new bushings
Place new bushings in the freezer for a short period to shrink them.
Heat the plate/housing for 10–15 minutes.
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Install bushings:
Some may drop in if the housing is hot enough and the bushing is cold enough.
Otherwise, tap in gently using a socket of the same diameter.
Install the positive stud insulator washer
Replace the small insulator washer on the positive stud so it is not forgotten later.
Install brushes and align the housings
Clean the brush mounting plate area.
Identify the side with the small isolation pad; this corresponds to the shielded brush lead location you marked during disassembly.
Screw the new brush leads onto the posts.
Slip brushes into their housings.
Seat the brush springs so the brushes press firmly against the commutator.
Tip: Brush springs can take patience and finesse. Take your time and make sure each brush is fully seated and spring-loaded. Refer to the video if you are struggling.
Set armature end play and install seals (gaskets vs RTV)
These starter motors use shims/gaskets/bushing thickness to control armature end play (the small amount of in-and-out float). Because rebuild kits cover multiple starter variants—and manufacturing tolerances vary—you must check clearance during assembly.
Alignment marks
The housings and end caps have cast alignment notches/raised marks that indicate correct orientation.
Highlighting the marks with a paint marker can make alignment easier during reassembly.
Pre-assembly for end play check
Move brushes back slightly so they “click” out of the way.
Apply a small amount of wheel bearing grease to hold shims in place (if shims are used).
Slide the armature into the main housing.
Release brushes so they snap onto the commutator.
Install the large main body O-ring.
Align and fit the end cap using the alignment marks; confirm the cap can seat without a significant gap.
Endplay check (armature float)
With the plates installed, use pliers to gently lift/lower the armature and feel the amount of in-and-out movement.
The target is a little play, but not much, and the armature must still spin freely.
If endplay is excessive
The video demonstrates removing a kit gasket to reduce excessive play.
Recheck movement after each change.
Top housing fit check
Test-fit the top gasket and planetary side housing (gears can be removed temporarily to make this easier).
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Look for a housing gap:
The housing should sit flush and snap into place cleanly.
If the gasket causes a large gap and prevents seating, remove that gasket.
Using RTV-type sealant instead of paper gaskets
If one or both paper gaskets are removed to achieve correct fit and end play, the use a thin RTV-type high-temp sealant as the sealing method:
Apply a very thin layer only at the sealing edges where a gasket is not used.
Reassemble and verify the housings seat flush with minimal visible gap.
Caution: Use sealant sparingly. Excess sealant can squeeze inward during assembly.
Final assembly
Install the long through-bolts with a small amount of anti-seize on the threads.
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Tighten by hand with a hand screwdriver until snug.
There is no specific torque value provided for these fasteners. Hand tight is sufficient.
Bench test before reinstalling on the motorcycle
Bench testing verifies correct electrical function before you reinstall the starter motor.
Clamp the starter motor securely in a vise.
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Connect jumper cables to a small motorcycle battery:
Positive (+) to the starter motor positive stud/nut
Negative (–) to the starter motor housing (ground)
Tap the negative connection to complete the circuit and confirm the starter spins.
Expected result:
The starter motor should spin up quickly and sound smooth.
Safety note: Keep hands, wires, and loose clothing clear of rotating parts during the bench test.
Troubleshooting
The starter motor will not spin on the bench
Confirm battery is charged and jumper cables have clean contact.
Confirm the negative clamp is on bare metal aluminum housing to provide a good ground.
Recheck brush installation: springs seated, brushes sliding freely, leads correctly installed.
Confirm the shielded brush lead is installed on the correct side (the shielded location).
The starter spins slowly or sounds strained
Verify the planetary gear cavity is properly greased.
Recheck bearing orientation and that the rotating assembly spins freely by hand.
Recheck armature end play: too little clearance can cause drag. Adjust gasket/shim/RTV strategy until it spins freely.
The housings will not seat flush
Verify alignment marks are matched correctly.
Test-fit without paper gaskets and recheck end play.
Use a thin RTV-type sealant only where gaskets were removed.
The thin housing cracked during bushing work
This typically happens from insufficient heat and too much force. Replace the damaged housing before proceeding.
FAQ
Do I need to remove the field coil magnets?
No. The rebuild process shown does not require removing the field coil magnets, and they are difficult to remove without cause.
Do I need to replace the bronze bushings?
No, but the kit often includes them in case yours have worn over the decades of use. If you replace them, use heat and patience to avoid cracking the housing.
How much armature end play is correct?
The guideline is: some back-and-forth play, but not much, and the armature must still spin freely. Because tolerances vary, check end play during assembly and adjust gasket/shim usage as needed.
What grease should I use?
We recommend using wheel bearing grease for packing the planetary bearing and the planetary gear cavity.
Should I use the paper gaskets from the kit?
Use them only if the starter seats properly and end play is correct. The video demonstrates removing one or both gaskets when they create excessive gap or end play, then sealing with a thin RTV-type compound.
Click here to find our Electric Starter Clutch Rebuild / Removal (For Kick Start Only)