Sears no longer sells the metric only kits and when they did, they had a lot of DIN metric and lacked a lot of JIS sizes. For example, they gave you a 11mm, 13mm 15mm, 16mm and 18mm but no 19mm...sometimes not even a 17. You can find them on
ebay and beef them up for JIS.
Like the all mighty Pin Head said: There is no 13mm on a stock cruiser or anything else Japanese.
I have a great little metric only kit made by Proxxon:
http://www.mogsrus.com/23650.html Covers JIS well but also includes the other metic sizes. I bought mine for less than listed here off a european website.
I also have a nice kit made by Blue Point (Taiwan Snapon) with FULL SAE and Metric. It has SAE but at least it has a full metric assortment and then I have the stuff for the odd muffler hanger, muffler clamp, battery cable bolt, radiator clamps, fuel line clamps, U bolt clamps, shock bolts, Warn winch and other SAE stuff that somehow often winds up on an otherwise Japanese truck.