This is a new item.
18 tooth for use with 420 chain.
17mm centre spline.
SIZE NOTES:
Centre Spline can be 17mm or 20mm depending on engine.
MOST are 17mm but please check before ordering.
Sprocket tooth size guide:
420 chain - Width between inner plates is 6.35mm, roller diameter 7.77mm
428 chain - Width between inner plates is 7.94mm, roller diameter 8.51mm