MOTO-MASTER Fusion Dual-Material Steel/Aluminium Rear Sprocket (black) for KAWASAKI KX 80, 85, 100 and SUZUKI RM 100 1983-2026

The MOTO-MASTER Fusion (noire) dual-material steel and aluminium rear sprocket is designed for KAWASAKI KX 80, KX 85, KX 100 and SUZUKI RM 100 from 1983 to 2026. The rear sprocket is the large sprocket bolted to the rear wheel hub. A dual-material sprocket combines steel teeth, which resist wear, with an aluminium centre that keeps the weight down: you get the service life of steel at a weight close to that of an aluminium sprocket.

Specifications

• Brand: MOTO-MASTER
• Manufacturer part numbers: 620063246, 620063247, 620063248, 620063249, 620063250
• Chain pitch: 420
• Steel toothed ring, aluminium centre
• Available versions: 46 Teeth: ref. 620063246; 47 Teeth: ref. 620063247; 48 Teeth: ref. 620063248; 49 Teeth: ref. 620063249; 50 Teeth: ref. 620063250
• Weight: 500 g
• Engine: 2-stroke

Choosing the right number of teeth

For the same bike, go for the number of teeth of your current sprocket (it's often stamped on it). More teeth on the rear sprocket shortens the gearing: more acceleration, lower top speed. Fewer teeth lengthens it. Even one or two teeth make a clear difference; if you change a lot, the chain length may need adjusting.

When to replace it?

• Teeth worn to a point or into a hook shape, worn down on one side only.
• Chain that lifts away from the sprocket when you pull it rearwards.
• Drivetrain noise, jerkiness or a chain that jumps under load.

Check the sprocket every time you service the chain. Always replace the rear sprocket, front sprocket and chain together: a new part running with worn ones wears out very quickly.

Fitting tips

1. Clean the hub and check that it isn't cracked or distorted.
2. Fit the sprocket the right way round (markings facing out) and tighten the bolts in a criss-cross pattern to the manufacturer's torque, with medium-strength threadlocker if the manual calls for it.
3. While you're at it, replace the front sprocket and the chain if they're worn.
4. Set the chain tension as per the manual, with the wheel aligned, then lube it with a suitable chain lube.
5. Recheck the bolt tightness and the chain tension after the first ride.

Why MOTO-MASTER?

In motocross, Moto-Master was working with the Red Bull KTM Factory Racing team as early as 2010, and it backed the MXGP world championship in 2015. On the technical side, the Flame profile of its discs is designed to improve cooling and go easy on the pads, and its Racing GP sintered pads use a backing plate with hooks (NRS technology) that stops the friction material from coming away.

Spare parts and items to plan

• Front sprocket : RFX · PBR
• Drive chain : AFAM A420MX2-G · AFAM A420R1-G
• Chain lube : LIQUI MOLY 400 ml · MUC OFF 400 ml

Frequently asked questions

What's the advantage over an aluminium sprocket?
The steel teeth last much longer, especially in mud or sand, for barely any extra weight.

Should the chain be replaced at the same time?
Yes, if it's worn: a stretched chain wears out a new sprocket in a few hours.

Compatibility

Check the exact model and year of your bike in the list below before ordering.

Fits:
KAWASAKI KX 80 2000
KAWASAKI KX 80 1999
KAWASAKI KX 80 1998
KAWASAKI KX 80 1997
KAWASAKI KX 80 1996
KAWASAKI KX 80 1995
KAWASAKI KX 80 1994
KAWASAKI KX 80 1993
KAWASAKI KX 80 1992
KAWASAKI KX 80 1991
KAWASAKI KX 80 1990
KAWASAKI KX 80 1989
KAWASAKI KX 80 1988
KAWASAKI KX 80 1987
KAWASAKI KX 80 1986
KAWASAKI KX 80 1985
KAWASAKI KX 80 1984
KAWASAKI KX 80 1983
KAWASAKI KX 85 2025
KAWASAKI KX 85 2024
KAWASAKI KX 85 2023
KAWASAKI KX 85 2022
KAWASAKI KX 85 2021
KAWASAKI KX 85 2020
KAWASAKI KX 85 2019
KAWASAKI KX 85 2018
KAWASAKI KX 85 2017
KAWASAKI KX 85 2016
KAWASAKI KX 85 2015
KAWASAKI KX 85 2014
KAWASAKI KX 85 2013
KAWASAKI KX 85 2012
KAWASAKI KX 85 2011
KAWASAKI KX 85 2010
KAWASAKI KX 85 2009
KAWASAKI KX 85 2008
KAWASAKI KX 85 2007
KAWASAKI KX 85 2006
KAWASAKI KX 85 2005
KAWASAKI KX 85 2004
KAWASAKI KX 85 2003
KAWASAKI KX 85 2002
KAWASAKI KX 85 2001
KAWASAKI KX 100 2026
KAWASAKI KX 100 2025
KAWASAKI KX 100 2024
KAWASAKI KX 100 2023
KAWASAKI KX 100 2022
KAWASAKI KX 100 2021
KAWASAKI KX 100 2020
KAWASAKI KX 100 2019
KAWASAKI KX 100 2018
KAWASAKI KX 100 2017
KAWASAKI KX 100 2016
KAWASAKI KX 100 2015
KAWASAKI KX 100 2014
KAWASAKI KX 100 2013
KAWASAKI KX 100 2012
KAWASAKI KX 100 2011
KAWASAKI KX 100 2010
KAWASAKI KX 100 2009
KAWASAKI KX 100 2008
KAWASAKI KX 100 2007
KAWASAKI KX 100 2006
KAWASAKI KX 100 2005
KAWASAKI KX 100 2004
KAWASAKI KX 100 2003
KAWASAKI KX 100 2002
KAWASAKI KX 100 2001
KAWASAKI KX 100 2000
KAWASAKI KX 100 1999
KAWASAKI KX 100 1998
KAWASAKI KX 100 1997
KAWASAKI KX 100 1996
KAWASAKI KX 100 1995
KAWASAKI KX 100 1994
KAWASAKI KX 100 1993
KAWASAKI KX 100 1992
KAWASAKI KX 100 1991
KAWASAKI KX 100 1990
KAWASAKI KX 100 1989
KAWASAKI KX 100 1988
KAWASAKI KX 100 1987
SUZUKI RM 100 2004
SUZUKI RM 100 2003