420 Sealed X-Ring Primary Chain Conversion – Sur-Ron Ultra Bee

Ditch the belt. Ride harder. Stay cooler.
The DirtyBike 420 Sealed X-Ring Chain Conversion System is built for Ultra Bee riders who push their machines to the edge. From fast trails to the brutal conditions of RedBull TKO. This chain drive was torture-tested at the 2024 RedBull TKO Extreme Enduro, where it took on rocks, mud, and hill climbs without a hiccup. Trusted by pro riders who need reliability and peak performance, not blown belts!

Why 420 Over 520?

Don’t get misled by overbuilt kits.
While 520 kits sound tougher, the extra size creates more friction and heat — which can lead to faster wear and early failure. The 420 size strikes the perfect balance:

• Less resistance

• Smoother articulation

• Longer chain life

• Cooler running under load

Key Features:

• 420 sealed X-ring chain – minimizes stretch and keeps dirt out

• Maintains stock gear ratio – no change to torque or speed

• Chain removal made easy – swap chains without removing swingarm

• More efficient than belt drive – better throttle response and range

• Quieter than open-link chain systems

• Includes a master link for fast service

Compatibility & Notes

• Fully compatible with OEM motor and most aftermarket setups

• If using the EBMX XUB-80 motor, the front sprocket will require slight modification — contact us for guidance

Pro Tip: Use All-Natural Lube

Pair this system with our eco-friendly chain lube for smoother performance and less mess on your swingarm or wheel.

Swingarm alignment tool

Buyers and Maintenance Guide

All Natural Lube