Yamaha Genuine RX50 / YSR50 Crankshaft 4U5-11400-00
Yamaha Genuine RX50 / YSR50 Crankshaft 4U5-11400-00
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Product Description
Brand new official Yamaha factory complete crankshaft assembly designed for classic vintage 50cc two-stroke geared motorcycles and minibikes. Precision-forged and dynamically balanced to exact factory metallurgical and rotational tolerances, featuring the robust 3R1-type heavy-duty rod design engineered to eliminate bottom-end vibration, restore primary compression, and handle high-RPM operation for a complete engine overhaul.
Vehicle Compatibility
Engineered explicitly for Yamaha classic air-cooled two-stroke 50cc geared sport and trail platforms.
Verified catalog fitment layout:
| Make | Model Family | Engine Type / Displacement | Model Years |
| Yamaha | RX50 / RX50CH | 49cc (2-Stroke Air-Cooled Geared Single) | 1980s |
| Yamaha | YSR50 / YSR 50 | 49cc (2-Stroke Air-Cooled Minibike Sport) | 1986–1992 |
| Yamaha | DT50R / DT50MX / TZM50 (Variants) | 49cc (2-Stroke Air-Cooled Geared Single) | Vintage Era |
Fitment & Technical Details
Check main bearing journals and oil seal mating surfaces for absolute cleanliness prior to installation. Warm the crankcase bearing housings evenly and press the new crankshaft assembly squarely into position without side-loading or hammering directly on the threaded shaft ends.Verification: Crankshaft spins freely with zero binding, axial play, or radial runout inside the matched crankcase halves.
Important: Please ensure the part number matches your motorbike before purchasing. If you have any questions about the part or its compatibility, feel free to contact us. We’re here to help!
At Dmmotorcycles, we’ve specialized in vintage and vintage sports motorcycles and parts directly from Japan since 1998. We stock a wide selection of rare genuine and high-quality aftermarket parts and continually update our inventory to meet growing demand.
Looking for a specific part? Don’t hesitate to ask! We may have it in stock even if it’s not listed online. If not, we’ll do our best to source it for you.
We’re also happy to provide guidance on installation and offer excellent after-sales support to ensure your satisfaction.
Shipping Information
We ship worldwide, carefully inspecting and securely packing all parts to ensure safe delivery. Your order will be insured and shipped quickly, with the best available shipping option chosen for speed and reliability.
Please note:
- All parts are shipped from Cyprus (Europe).
- Customers outside the EU may incur additional import taxes based on the value of the item.
