RK Racing Chain M520HD-120-06 M520HD-120 120-Link Heavy-Duty Chain

In this review the RK Racing Chain M520HD-120-06 is examined for riders who need a durable, heavy-duty replacement chain for 400cc street bikes and off-road machines. The bottom line: this 120-link 520 series chain stands out for its pre-stressed and pre-stretched construction, which reduces early adjustment and helps maintain tension longer than many competitors. It is realistic to expect solid value and mechanical reliability for everyday and spirited riding, while being aware of some mixed feedback on long-term corrosion and occasional master link issues.

Key Features

• Made with Japanese steel: Built in Malaysia to Japanese specs, the construction provides consistent strength and material quality for drivetrain use.
• Two-point riveted pins: The double rivet design improves pin retention and resists separation under load for safer operation.
• Curled bushings: Curled bushings increase contact area and help the chain run smoothly on sprockets.
• Pre-stressed and pre-stretched: Factory conditioning reduces early stretch and minimizes the need for immediate adjustments after installation.
• Heavy-duty tensile rating: Rated to 7700 pounds/ft maximum tensile strength, suitable for strong loads up to the specified capacity.
• Master link clip type: Uses a clip master link for easy assembly and serviceability in the field or garage.

Who It's For

The M520HD-120-06 is best for riders of small to mid-displacement motorcycles - up to about 400cc - who want a stout, serviceable 520-series chain that can handle street and off-road use. Enthusiasts who value easy installation and less initial adjustment will appreciate the pre-stretched condition and the clip master link.

Riders who need premium corrosion protection or expect extreme high-mileage life without any maintenance may want to consider higher-end sealed O-ring chains or chains with dedicated rust-resistant coatings, since some users report rust and stretch over extended use.

Pros & Cons

Pros

• Solid construction with Japanese steel and two-point rivets for reliable strength under load.
• Pre-stressed design reduces break-in adjustments and helps maintain chain tension sooner.
• Good value per pack with six chains included for spares or multiple bikes.

Cons

• Not an O-ring chain and has limited rust resistance compared with sealed chains, so it requires regular maintenance to avoid corrosion.
• Customer reports mention occasional master link or stretch issues under heavy or long-term use.

Specifications

Series	M520HD (520 Series)
Links	120 links per chain
Pin to pin center	15.875mm
Pin length	18.80mm
Maximum tensile	7700 pounds/ft
Weight	3.65 lb per 100 links
Master link type	Clip

Our Verdict

The RK Racing Chain M520HD-120-06 is a practical, heavy-duty 520-series chain that delivers strong construction, easy installation with a clip master link, and less initial stretch thanks to pre-stressing. It represents good value for riders of up to 400cc machines who maintain their drivetrain; those prioritizing rust resistance or sealed O-ring protection should consider alternatives.

Frequently Asked Questions

Is this chain suitable for a 400cc street bike?
Yes - the chain is rated for up to 400cc street and off-road use and is designed to meet Japanese specs for that class.

Does the chain come pre-stretched?
Yes - the chain is pre-stressed and pre-stretched to reduce early adjustment and initial elongation after installation.

What type of master link does it use?
The chain uses a clip-type master link for straightforward assembly and servicing.