1. Antique, Vintage, Historic Motorcycle Parts For Sale
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  3. KTM 54630318400

KTM 54630318400 Crankshaft 73MM 6D

fits model: 300mxc, Mxc, Sx, 300. make: Ktm. year: 1997–2003.

54630318400 Ktm 98 300mxc Crankshaft Assembly 73mm Mxc Exc Sx 300 1997 - 2003 6d

( Manufacturer Part Number: 54630318400 ), ( Part Type: Crankshaft ), ( Country Of Origin: Austria )

Review KTM Crankshaft Assembly 73mm Exc 6d fits 300MXC MXC SX 300 1997–2003

The **KTM 54630318400 98 300MXC Crankshaft (73mm MXC EXC/SX 300, 1997 2003, 6D)** is a high-performance, precision-engineered component designed exclusively for KTM s legendary 300cc MXC, EXC, and SX models from the late 1990s through the early 2000s. This crankshaft is a critical part of the engine s drivetrain, crafted from high-grade forged steel to ensure durability, strength, and optimal power delivery under the demanding conditions of motocross and off-road racing. Measuring **73mm in stroke length**, it is specifically engineered to complement the 300cc engine s displacement, striking a balance between torque and revving capability for aggressive riding styles. The **6D (six-degree) design** enhances smoothness and reduces vibration, allowing for a more refined throttle response and improved rider comfort during high-speed maneuvers or prolonged laps.

This crankshaft is a direct-fit replacement for the original equipment found in the **1997 2003 KTM 300MXC, EXC, and SX models**, ensuring compatibility with the stock engine block, connecting rods, and other drivetrain components. Its robust construction and precision machining make it ideal for both restoration projects and performance upgrades, as it maintains the factory s intended specifications while offering enhanced longevity. Whether you re restoring a classic bike to its original glory or pushing the limits of a modified rig, this crankshaft delivers the reliability and performance expected from KTM s high-performance parts. Built to withstand the rigors of off-road racing, it is a testament to KTM s engineering excellence, ensuring that your 300cc machine runs with the same precision and power it was originally designed for.

### **Pros and Cons of buying a KTM 54630318400 Crankshaft (73mm, 1997 2003 300MXC/6D, 1998 2003 SX 300)**

#### **Pros:**

1. **Performance Improvement** The 73mm crankshaft is a popular upgrade for older KTM 300MXC/6D and SX 300 models, offering better torque and power delivery, especially at lower RPMs. This can make the bike feel more responsive and engaging, particularly in off-road or aggressive riding scenarios.

2. **Compatibility** This crankshaft is designed specifically for the 1997 2003 300MXC/6D and 1998 2003 SX 300 engines, ensuring a direct fit without major modifications. It s a straightforward swap for those looking to enhance their bike s power output.

3. **Durability** KTM components, even aftermarket upgrades like this crankshaft, are generally built to withstand high-stress conditions. The 73mm crank is a proven part in the aftermarket, often used in racing and heavy-duty riding.

4. **Cost-Effective Upgrade** Compared to full engine rebuilds or major modifications, swapping the crankshaft is relatively inexpensive. It provides noticeable performance gains without requiring extensive labor or additional parts.

5. **Aftermarket Support** The KTM 300MXC/6D and SX 300 have a strong aftermarket following, meaning you ll find plenty of resources, forums, and parts to support this upgrade. Tuning options (like ECU remaps) can further optimize the crankshaft s benefits.

6. **Reliability** If sourced from a reputable supplier (e.g., KTM Performance Parts, trusted dealers, or well-reviewed sellers), this crankshaft should be reliable and free from common manufacturing defects.

7. **Aesthetic and Tuning Potential** Beyond performance, upgrading the crankshaft can be part of a broader tuning project, allowing you to pair it with other modifications (e.g., exhaust, carburetor, or suspension upgrades) for a fully customized bike.

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#### **Cons:**

1. **Limited Power Gains Without Additional Modifications** While the 73mm crank improves torque, it may not significantly boost top-end power unless paired with other upgrades (e.g., a larger carburetor, exhaust, or ECU tune). Expect noticeable changes in mid-range power but not necessarily a dramatic increase in high-RPM performance.

2. **Potential for Increased Stress on Other Components** A crankshaft upgrade can increase engine stress, particularly if the rest of the engine (e.g., pistons, rods, or bearings) is worn or outdated. This may require additional maintenance or upgrades to other components to prevent premature failure.

3. **Installation Complexity** Swapping a crankshaft is not a beginner-level task. It requires disassembling the engine, removing the old crank, installing the new one, and reassembling everything with precision. If you lack mechanical experience, labor costs or professional installation may be necessary.

4. **Compatibility Risks** While this crankshaft is designed for the specified models, there s a small chance of fitment issues if the engine has been heavily modified or if parts (e.g., timing chain, balancer) are worn. Always verify compatibility before purchasing.

5. **Warranty Void** Installing an aftermarket crankshaft will void the manufacturer s warranty on the engine. If you plan to keep the bike long-term, this could be a concern, especially if the original engine is still under warranty.

6. **Market Availability and Pricing** Prices for this crankshaft can vary widely depending on the supplier. Some sellers may charge premium prices, while others might offer deals. Researching multiple sources and reading reviews can help avoid overpaying or purchasing counterfeit parts.

7. **Learning Curve for Tuning** If you plan to pair this upgrade with an ECU tune or carburetor adjustments, you ll need to understand how these changes interact with the crankshaft. Improper tuning can lead to rough idle, poor performance, or even engine damage.

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### **Conclusion:**

The **KTM 54630318400 73mm crankshaft** is a solid upgrade for the 1997 2003 300MXC/6D and 1998 2003 SX 300, offering measurable improvements in torque and mid-range power. It s a cost-effective way to enhance performance without a full engine rebuild, and it s well-supported by the aftermarket. However, it s not a "set-and-forget" upgrade it requires careful installation, potential additional modifications, and an understanding of how it interacts with other engine components.

If you re an experienced rider or mechanic, this upgrade can be highly rewarding, transforming your bike into a more capable off-road or track machine. For less experienced riders, it may be worth considering professional installation and pairing it with other upgrades (like a tune or exhaust) to maximize benefits.

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### **Recommendation:** - **Buy it if:**

- You re looking to improve torque and mid-range power for better throttle response.

- You re comfortable with basic engine disassembly or have access to a mechanic.

- You plan to pair it with other upgrades (e.g., carburetor, exhaust, or ECU tune) for optimal results.

- You ve verified the crankshaft s compatibility with your specific engine and model year.

- **Avoid it if:**

- You re not prepared for the installation process or lack mechanical experience.

- Your engine has significant wear (e.g., worn bearings, rods, or pistons) that needs addressing first.

- You expect dramatic power gains without additional modifications.

- You re on a tight budget and can t afford potential additional costs (e.g., labor, tuning, or extra parts).

**Final Verdict:** This crankshaft is a **highly recommended upgrade** for those who want to breathe new life into their older KTM 300MXC/6D or SX 300. Just ensure you approach it with realistic expectations and proper preparation. If in doubt, consult with a KTM specialist or experienced tuner before purchasing.

Details:

73mm stroke crankshaft P/N removed from a 1998 300MXC two. This crank has .046 lateral play at the rod tip, which translates to .0006 radial or near new condition as per Cooks Correlation chart. This crankshaft is in very good condition and came from a low time garage queen.

part #: 54630318400 price

  • $385.00

specifications cyclevintagee:

  • for models: 300mxc, Mxc, Sx, 300
  • for makes: Ktm
  • for years: 1997-2003
  • mpn: 54630318400
  • part type: Crankshaft
  • country of origin: Austria

shipping cyclevintagee:

  • service: UPS Ground
  • type: Fixed
  • cost: $19.00
  • class: Standard
  • transit: 2-6 Days
  • carrier: UPS

payments cyclevintagee:

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offer cyclevintagee:

  • options: Ship-to-home
  • best offers: True
  • started: May 7, 2026
  • sold: 0
  • availability: In Stock
  • quantity: 1

returns cyclevintagee:

  • paid by: Buyer
  • policy: Returns Accepted
  • time: 14 Days

seller cyclevintagee:

  • # reviews: 5512
  • city: Branson, Missouri
  • rating: 100.0%

general cyclevintagee:

  • Parts Accessories > Motorcycle Scooter Parts Accessories > Other Motorcycle Scooter Parts Accessories
  • condition: Used
for models: 300mxc, mxc, sx, 300, for makes: ktm, for years: 1997-2003, part type: crankshaft, country of origin: austria,
category: motorcycle parts > motorcycle scooter parts accessories, sku: 22201106707381711,
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1 offer $385.00 USD
  • Used. Offer #1 priced at $385.00 + $19.00 shipping estimate = $404.00* total. 0006" radial play (or near new condition) as per the Cooksey Correlation chart. 73mm stroke crankshaft P/N removed from a 1998 300MXC two stroke.+$19.00 shipping

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