How to Clean a Motorcycle Carburetor
Disassemble, clear clogged fuel jets, flush internal passages, and reassemble a motorcycle carburetor to restore smooth engine idle and throttle response.
- Read the tools, materials, safety notes, and steps below for free.
- Tap Start Camera Coach when you want hands-free voice help.
- Allow camera and microphone. Point your phone at the work; the coach watches your progress and tells you the next step.
🧰 Required Tools & Equipment
- ✓ JIS or Phillips screwdriver
- ✓ Small flat-blade screwdriver
- ✓ Carburetor cleaning wire kit
- ✓ Compressed air blow gun
- ✓ Magnetic parts tray
- ✓ Safety glasses
📦 Materials & Supplies
- ✓ Aerosol carburetor cleaner
- ✓ Nitrile chemical-resistant gloves
- ✓ Lint-free microfiber shop towels
- ✓ Replacement float bowl gasket
⚠️ Safety Checkpoints & Warnings
- • Wear chemical splash goggles; aerosol carb cleaner will shoot backwards out of intersecting passages directly toward your eyes.
- • Work in a well-ventilated area outdoors or under an exhaust hood away from open flames, pilot lights, and sparks.
- • Keep rubber O-rings, diaphragms, and plastic floats away from harsh solvent sprays to prevent swelling or degradation.
📋 Step-by-Step Guide (6 Steps)
Remove the Float Bowl and Gasket
Set the carburetor upright on a clean rag. Remove the four corner screws holding the float bowl using a properly sized JIS screwdriver to avoid stripping the soft brass or zinc heads. Carefully lift off the bowl and peel away the perimeter rubber gasket.
- • Float bowl is separated from the carb body resting in parts tray
- • Brass jets and plastic float are clearly exposed underneath
- • Using an ill-fitting Phillips bit that cams out and strips soft zinc screws
- • Prying the bowl off aggressively and gouging the mating aluminum surface
Remove Float and Float Needle
Push the float pivot pin out sideways with a small punch or wire. Lift the plastic or brass float straight out while catching the tiny suspended float needle valve. Store the needle and pin safely in the parts tray.
- • Float, pivot pin, and needle valve are resting together in the parts tray
- • Float needle seat chamber is empty and accessible
- • Pulling the float upward before removing the hinge pin, bending the delicate brass tang
- • Dropping the spring-loaded float needle valve onto the floor
Extract Main Jet, Pilot Jet, and Emulsion Tube
Use a precision flat-blade screwdriver that fits the full width of the brass jet slots. Unscrew the pilot (slow) jet from its deep recess, then remove the main jet and the underlying emulsion tube (needle jet holder).
- • Main jet, pilot jet, and emulsion tube removed and placed in tray
- • Threaded jet towers in the carb body are completely empty
- • Using a narrow flat-blade screwdriver that snaps off one side of the soft brass jet slot
- • Forgetting to push out the emulsion tube sitting above the main jet
Clear Jet Orifices and Internal Passages
Spray carb cleaner through each brass jet, then gently pass an appropriately sized soft carb wire through the central hole to dislodge hardened varnish. Insert the straw of the carb cleaner directly into each passage in the carburetor body, spraying until solvent flows cleanly out the corresponding intake and throat ports. Blow all passages dry with compressed air.
- • Pinpoint beam of light is visible through center hole of both pilot and main jets
- • Solvent and compressed air exit smoothly from transition ports in carb bore
- • Forcing oversized steel wire into tiny pilot jet holes, enlarging and ruining factory fuel calibration
- • Failing to look directly through the jet towards a light source to verify clear orifice
Clean Float Bowl Basin and Overflow Tube
Spray the interior of the float bowl with carb cleaner and scrub any green or brown varnish residue using a soft rag or nylon brush. Shoot compressed air down the brass overflow tube inside the bowl to ensure it is completely clear of debris.
- • Float bowl basin is bright silver/aluminum with zero sediment or varnish flakes
- • Air flows freely through bottom bowl drain nipple
- • Leaving loose varnish flakes in the bowl corners that instantly re-clog the pilot jet once fuel is restored
- • Using abrasive steel wool that leaves conductive metal strands inside the bowl
Reinstall Jets, Float Assembly, and Bowl
Thread the emulsion tube, main jet, and pilot jet back into their towers and snug them down firmly by hand. Hang the float needle on the float tang, place the assembly into position, and slide the pivot pin through the posts. Install a fresh bowl gasket, position the float bowl, and evenly tighten the corner screws in a crisscross pattern.
- • Float moves smoothly up and down on hinge pin without binding
- • Float bowl is flush against carb body with gasket evenly seated all around
- • Overtightening brass jets causing thread shear inside carb body
- • Pinched or twisted float bowl gasket resulting in immediate fuel leak
Credit: inspired by an original tutorial by Motorcyclist Magazine — watch the original on YouTube.
Don’t have everything?
- No Carburetor cleaning wire kit? Single strand stripped from copper electrical wire (never use hard steel guitar strings or drill bits)
- No Compressed air blow gun? Can of compressed electronic duster / keyboard air