Im switching a 03 sportster over to a chain drive if im running a 51 tooth rear sprocket what sizefront sprocket would.I need to run to obtain a smilar to stock ratio

 

this service manual is for the five years evo sportster had chain drive from the factory. the manual will give the stock sizes! cheers from montana

 

22T trans sprocket would be slightly below and a 23T would be slightly above.