Posted by The Moto Store on Oct 30th 2026
Carburetor Rebuild Kit: What's in It and How to Pick One
Short answer: a carburetor rebuild kit replaces the parts that wear or harden inside a carb: the float needle (float valve) and seat, the bowl gasket and O-rings, the pilot and main jets, and on many kits the jet needle and springs. Buy one when the bike floods, leaks fuel from the bowl overflow, or idles rough after sitting. Match it by make, model and year, buy one kit per carburetor, and replace the needle and seat even if they look fine. If only one part is bad, a needle-and-seat assembly, an accelerator pump kit, or a petcock repair kit is the cheaper fix.
What is in a carburetor rebuild kit
Contents vary by brand and carb, so check the product page, but a kit for one carburetor normally covers these parts.
| Part | What it does | What goes wrong |
|---|---|---|
| Float needle (float valve) and seat | Shuts off fuel when the bowl is full | Tip hardens or grooves; fuel runs out the overflow |
| Float bowl gasket | Seals the bowl to the body | Shrinks; fuel seeps at the seam |
| Pilot and main jets | Meter fuel at idle and wide open | Varnish blocks the pilot; bike needs choke to idle |
| Jet needle (many kits) | Meters the midrange | Wears a flat; rich, blubbery midrange |
| Springs and screw O-rings (many kits) | Hold the idle and mixture screws in place and seal them | O-rings crumble; idle hunts |
| Small O-rings and washers | Seal the seat, choke plunger and drain screw | Dry out and leak |
Kits come with stock jet sizes for the listed model. If you have rejetted for a pipe or altitude, keep your jets and use the kit for the seals, needle and seat. Supplier contents lists do not name the float or a CV slide diaphragm, so plan on buying those separately.
Rebuild kit or just a clean?
Fuel left sitting plugs the pilot jet first. If the bike starts on choke, idles badly without it, and otherwise runs clean, carb spray and compressed air often fix it with no parts.
Reach for a kit when fuel drips from the overflow tube or bowl seam, when the bike floods after a cleaning, when the idle will not settle after you set the mixture screw, or when the carb has never been apart on a bike more than ten years old. In each case the rubber parts are done, whatever they look like.
Rebuild kit vs repair kit vs single parts
Category names overlap between brands.
| Kit | What you get | Buy it when |
|---|---|---|
| Carburetor rebuild kit | Float valve, gaskets, O-rings and jets; many kits add a jet needle and springs | Full refresh on a motorcycle or ATV carb |
| Carburetor repair kit (snowmobile, PWC) | Diaphragms, gaskets, needle and seat, check valves | Mikuni, Keihin or Tillotson pumper carbs on sleds and watercraft |
| Needle and seat assembly | Float valve and seat only | Overflow is the only symptom and the jets are clean |
| Accelerator pump rebuild kit | Pump diaphragm and its small seals; see the listing for contents | Bog or cough when you crack the throttle on a pumper carb |
| Petcock (fuel tap) repair kit | Seals and diaphragm for the tap; see the listing for contents | Fuel weeps at the tap, or a vacuum petcock will not flow |
On a pumper carb the accelerator pump diaphragm squirts fuel when the throttle opens. When it tears, the bike bogs off idle even though it idles and pulls fine, so check the pump before you blame jetting. Petcocks fail the same way: a hardened diaphragm leaks at the lever or stops flow in ON, and a repair kit fixes it without a new tap.
How to match a kit to your bike
Start with make, model and year. Manufacturers change carburetors between model years without changing the bike's name, so use the year on your title and read the application list on the product page.
Count your carburetors. One kit serves one carb body: a twin needs two, an inline four needs four.
If the bike has had a carb swap, read the maker's code stamped on the body or bowl (Mikuni, Keihin and Tillotson all stamp one) and match by carb model and bore instead.
Brand coverage in our catalog: All Balls Racing has the longest list, including a Polaris series. Shindy lists Honda and Yamaha kits among others. Psychic, ProX and Bronco add more dirt bike and ATV kits. SPI, Vertex and Wavewerx cover snowmobile and PWC carbs.
Doing the job so it stays fixed
Clean the outside before opening the carb so grit stays out of the passages. Count the mixture screw turns out before removing it and set the new screw the same. Replace the needle and seat as a pair; a new needle on a worn seat still leaks. Set float height to the manual figure, with the float tang just touching the needle without compressing its spring. Fit the bowl gasket dry. Drain the old fuel, add an inline filter, and check the petcock screen while the tank is empty, because stale fuel killed the last set of parts.
What we carry
Carburetor parts live under Fuel & Air.
- Carburetor Rebuild Kits, more than 1,200 kits from All Balls Racing, Shindy, Psychic, Bronco, K&L Supply and ProX
- Carburetor Kits, SPI, Vertex and Wavewerx repair kits for snowmobile and PWC carbs
- Needle & Seats, Mikuni needle valve assemblies and SPI Tillotson needle-and-seat sets
- Accelerator Pumps, All Balls Racing pump rebuild kits
- Petcocks, All Balls Racing and K&S fuel tap repair kits
- All Balls Racing Carburetor Rebuild Kit 26-1652
- Psychic Carburetor Rebuild Kit XU-07436
- All Balls Racing Accelerator Pump Rebuild Kit 46-3012
FAQ
Q: Do I need one rebuild kit per carburetor? A: Yes. A kit holds the parts for one carb body, so a twin needs two and an inline four needs four. Where a brand sells a per-bike set, the product title or application list says so.
Q: Can I reuse my jets and install only the seals from the kit? A: Yes, and you should if the bike has been rejetted for an exhaust, intake or altitude. The seals, needle and seat are the wear parts; keep the jets tuned for your setup.
Q: The carb still overflows after a rebuild. What did I miss? A: Usually float height or dirt under the new needle. Recheck the float height against the manual, make sure the seat O-ring is seated and the seat is tight, and run a fresh fuel line with a filter. A fuel-logged float also overflows and needs its own replacement.
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