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Available sizes: 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310
Fits all motorcycles equipped with Mikuni VM (VM16-VM44), TM (TM24-TM38), or TMX series carburettors
Note: fitment is determined by carburetor model, not bike model. Verify your carburettor series before ordering.
Need parts for a different brand, model or year?
We stock gear for many bikes. If you don't see your model, reach out and we'll source it for you.
Not sure about something?
Ask us anything before you buy. We're glad to help.
The ProX 47.XXX main jet controls fuel delivery at high throttle - from approximately three-quarter throttle to wide open. It is the primary jet for tuning top-end fuelling on Mikuni round slide and flat slide carburettors.
Machined from brass to OEM Mikuni tolerances. Dimensions: 11.5mm length, 5.2mm thread outer diameter, 6mm hex (large hex type). Made in Japan. ProX part numbers follow the 47.XXX format, corresponding directly to Mikuni OEM designation 4/042-XXX. Example: ProX 47.200 equals Mikuni 4/042-200.
The 190 to 310 size range covers standard jetting for most 65cc to 250cc two-stroke motocross engines running Mikuni carburettors. If the engine runs lean at full throttle - overheating, flat power, popping on deceleration - go up a size. If it four-strokes or loads up at wide open throttle, go down.
Sold individually.
Available sizes: 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310
Fits all motorcycles equipped with Mikuni VM (VM16-VM44), TM (TM24-TM38), or TMX series carburettors
| Main Jet size | 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310 |
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We ship worldwide every day via DHL. Delivery within the EU is typically 2–3 business days.
We ship to every country DHL serves. Orders shipped to EU destinations qualify for free DHL shipping once the cart subtotal reaches €150. Orders shipped outside the EU are charged live DHL rates, calculated automatically at checkout.
You have 30 days from delivery to return any item in original condition. Full policy →
Pro-X Racing Parts is a European specialist in engine rebuild components for motocross and off-road competition. The range covers forged pistons, connecting rods, bearings, seals, gaskets, and complete rebuild kits for 2-stroke and 4-stroke engines across all major makes and model years.
Each Pro-X piston is manufactured to OEM bore dimensions and surface finished for direct bolt-in fitment without machine work. Kits are packaged per-engine application and include all components required to complete a piston replacement or full top-end rebuild. Pro-X covers an extensive model matrix from current production back through older competition bikes.
