chain length 17/34 sprockets?

[jmink427]

wanting to go to a 30 tooth back sprocket... how much shorter should I go on the chain length? 75 xs650.. I think the stock chain is 104.. Maybe a 102?

 

[jayel]

each link/tooth is .625 so the sprocket is only 2.5 smaller circumference than stock 34, you shouldn't need to remove any links