Came across this on another site and maybe it can help. Not exact but it should get you close when wondering how long to get that new chain when you put on another swingarm...
Chain Guide for Extended Swing Arms
Here is a little info to help out when you are installing a extended swing arm.
Just for a reference a Busa comes with a 112 link chain.
This is a reference.
Swing arm Extension From Stock 0-3" 3-6" 6-9" 9-12" 12-15"
Stock 520/525/530 Chain +10 links +20 links +30 links +40 links +50 links
Stock 630 Chain +10 links +20 links +30 links +40 links +40 links
If this chart does not fit your exact length of stretch you can also figure out your chain length by adding 10 pins for every 3" you stretch your bike
1980 LTD (changed over the years), 1979 LTD (being rebuilt), 1977 KZ turbo and various KZ's in various states of build. KLX110
