The Conversion Kit/Crank Set is NOT compatible with 2 inch/50mm-51mm(inner diameter) BOTTOM BRACKET(refer to the third picture)
Compatible with 44mm(Outer Diameter) bottom bracket; Outer diameter of 2 cups: 34.5mm/1.358 inch which is compatible with 44mm OD bottom bracket (refer to the Fourth picture)
Also can be used on 2 stroke 66cc/80cc motorized bicycle(pls measure yours BB before shopping), the length of the crank is 266mm/10.47inch.
This conversion kit end up as/with a square taper;the crank of kit is same as the crank that comes with the 4 stroke gas motor kit(if your 4 stroke gas motorized bicycle was installed with original cranks, you can shopping without doubt, if not same cranks, pls measure yours BB before shopping);
If your bike is with 2 inch bottom bracket like 26" beach cruiser huffy with 51mm bottom bracket, you have to buy a BB Bottom Bracket Conversion converter (American to Euro) from your local shop or from CDHpower Amazon store.(refer to the fifth and sixth pictures pls); Any questions,please contact us firstly! we can help you solve the problem until you are satisfied.