This 10 tooth sprocket fits 49cc
and 66/80cc 2 stroke bicycle engines.
With this narrower output sprocket you can use a
BMX chain (410 chain), regular bicycle chain
or standard kit chain (415)
Outer Diameter: 45.9mm, 1.8inches, 1 13/16 inches
Center Hole Diameter: 14.57mm, .56inch.
The slot for the woodruff key is approximately
2.5mm (Woodruff Key Not Included).