JT Sprockets

Online Catalogue

Yamaha YBR125 (3D9,51D)

2007 to 2014

Front Sprocket

Steel Front Sprocket

Part Number: JTF548

Teeth: 14

Available Sizes: 13, 14

Rear Sprocket

Steel Rear Sprocket

Part Number: JTR838

Teeth: 45

Available Sizes: 31, 35, 36, 37, 38, 39, 42, 43, 45, 49, 54

Drive Chain

Pitch: 428

Length: 118

Please note that the chain shown in this listing is for size reference only. For the correct chain type and grade, please refer to the vehicle's manufacturer manual.

Gear Ratio Chart

TeethFront Sprocket
1314
Rear Sprocket312.38
-25.8%		2.21
-31.1%
352.69
-16.2%		2.50
-22.2%
362.77
-13.8%		2.57
-20.0%
372.85
-11.5%		2.64
-17.8%
382.92
-9.1%		2.71
-15.6%
393.00
-6.7%		2.79
-13.3%
423.23
+0.5%		3.00
-6.7%
433.31
+2.9%		3.07
-4.4%
453.46
+7.7%		3.21
standard
493.77
+17.3%		3.50
+8.9%
544.15
+29.2%		3.86
+20.0%

Lower gear ratios allow for higher top speeds.

Higher gear ratios increase torque for better acceleration.

Full Gear Ratio Chart (pdf)