I've got a set of perfectly fine Race Face North Shore cranks and a top of the line Race Face Isis DH BB from a few years ago that I'd like to use on a new play bike... except that the E.13 bashguard is cracked to pieces and I can't find a 5 bolt E.13 chainguide anywhere. Do they still exist or is this $350 crank and bb setup from just a few years ago useless now?