I already have two lock cores. Can I buy...
I already have two lock cores. Can I buy two more that are keyed the same as the two I already have?
Yes, talk to a Yakima dealer (like your local bike shop) and they can order the lock cores for you. If you really only need two, it'd be far easier (and only ~$5 more expensive) to order the 4-pack of SKS lock cores.http://www.backcountry.com/store/YAK0018/Yakima-SKS-Lock-Cores-4-pack.html