Buy Polini PWK Jets
Is your scooter running poorly after a modification to the cylinder, exhaust, or air filter? Or does the mixture just feel off? With the right jet for your Polini PWK carburetor, you can fine-tune the fuel mixture precisely and prevent engine damage.
What jets do in your Polini PWK carburetor
The jet determines how much fuel mixes with the air in your carburetor. Changing one size up or down can affect starting, acceleration, and top speed. In practice, you usually swap two jets: the pilot jet, active up to around a quarter throttle, and the main jet, active at high load and full throttle.
Which size Polini PWK jet do you need
The right size depends on your whole setup: engine cc, exhaust, air filter, and riding style. Weather matters too; what runs well on a warm summer day may require a different size in autumn.
If your jet is too small, the engine bogs at full throttle, runs hotter, and responds less well. Running too lean can cause damage. When in doubt, start richer and work step by step down. If your jet is too large, you’ll lose pull and hear the typical four-stroke sound at full throttle. Usually safe, but not optimal.
Single jet or complete Polini PWK jet kit
If you already know the size you need, a single jet is often enough. If you still have to tune or just changed your setup, a complete jet kit is more convenient. That way you have a range of sizes on hand and can adjust step by step without ordering a single size each time. Kits exist for pilot jets and main jets.
Note: the name PWK doesn't tell the whole story. Not every jet is interchangeable between Polini, Keihin, OKO, and other variants. Always check jet type, thread, and shape before ordering.
Ordering Polini PWK jets
First choose whether you want a pilot jet, main jet, or a complete kit. Then pick a size range that fits your setup and tune in small steps. If you're unsure, contact us via the contact page with your carburetor type and setup, and we'll help you out.
Frequently asked questions about Polini PWK jets
Are Polini PWK jets compatible with Keihin PWK?
Sometimes yes, sometimes no. The PWK name alone isn't enough. Always verify the exact jet type and thread. If they match, they're often interchangeable, but don't rely solely on the brand name.
How do I recognize the size of my current jet?
The size is usually stamped on the jet. Clean it first to read the numbers better. Also note whether it's a pilot or main jet; those sizes aren't directly comparable.
When should I choose a jet kit versus a single jet?
A kit is handy if you still have to tune or recently changed your setup. A single jet makes sense if you know exactly which size you need and just want to replace it.
What are the symptoms of a jet that's too small or too large?
A too-small jet causes bogging at full throttle, heat spikes, and a light gray spark plug. A too-large jet results in less pull, a dark spark plug, and sometimes extra smoke. Change only one thing at a time and note what you did.
What should I watch for when tuning my carburetor?
First ensure the basics are in order: a clean carburetor and a good spark plug. Start with a main jet slightly too large, take a test ride, and check the spark plug condition. Then adjust step by step.