RK Racing Chain 520-SO-108 Steel O-Ring 108 Link Chain - Durable Ride

In this review the RK Racing Chain 520-SO-108 is evaluated for riders seeking a balance of durability and affordability in a sealed chain. The bottom line: this chain is a sensible upgrade for low to mid-range motorcycles up to 400cc because its Nitrite Butadiene O-ring construction holds lubrication well and delivers smooth power with minimal seal drag. Installers should expect a well-greased, functional chain that represents strong value, though fit and master link experience may vary between bikes.

Key Features

• O-ring construction: Nitrite Butadiene O-rings seal in lubrication to reduce wear and keep power delivery smooth over time.
• Compatibility: Designed for low to mid-range motorcycles and rated up to 400cc for both street and off-road use, offering flexibility for mixed riding.
• Tensile strength: A 6,900 lb tensile rating provides a reliable safety margin for typical single-cylinder and twin motorcycles up to the recommended horsepower.
• Performance balance: The SOs seal formulation minimizes seal ring drag, helping retain more usable horsepower in everyday riding scenarios.
• Complete kit: Comes with a clip-type master link so the chain is ready to install without sourcing extra hardware.

Who It's For

The 520-SO-108 is best for riders of street and off-road motorcycles up to 400cc who want a sealed chain that offers a strong combination of durability and affordability. It suits commuters, dual-sport riders, and weekend trail users who prefer the lower maintenance of an O-ring chain while retaining smooth power transfer.

Racers or high-horsepower machines above 60 HP should look elsewhere for heavier-duty or X-ring performance chains. Likewise, anyone who needs an exact fit for an uncommon drivetrain should verify link count and width prior to purchase, since some customers report mixed experiences with fit and master link handling.

Pros & Cons

Pros

• Good build quality and lubrication out of the box, which reduces initial break-in fuss.
• Durable O-ring seals that preserve internal lubrication and prolong chain life.
• Versatile use for both street and off-road riding up to 400cc and 60 HP.

Cons

• Some riders report mixed fitment and master link installation experiences depending on the bike and sprocket alignment.

Specifications

Chain Model	520-SO-108
Links	108
Tensile Strength	6,900 lbs
Max CC Rating	400cc street / 400cc off-road
Max Horsepower	60 HP
Weight per 100 Links	3.39 lbs
Max Chain Width	21.7 mm
Master Link Included	Clip type

Our Verdict

The RK Racing Chain 520-SO-108 is a practical choice for riders of up to 400cc bikes who want a sealed chain that balances low maintenance with solid durability. It is good value thanks to a robust tensile rating and effective O-ring sealing, though buyers should confirm fitment and be prepared for occasional master link fiddliness during installation.

Frequently Asked Questions

Is this chain suitable for off-road use?
Yes, the 520-SO-108 is rated for off-road use up to 400cc, offering O-ring sealing that helps keep grit out and lubrication in.

Does it come with a master link?
Yes, a clip-type master link is included for installation, though user reports on ease of installation are mixed.

What is the maximum horsepower rating?
The chain is rated to handle up to 60 HP, which covers most low to mid-range motorcycles within the stated CC limit.