The kafka helm chart is not maintained by CORD, but it is available online at: https://github.com/kubernetes/charts/tree/master/incubator/kafka
To install kafka you can use:
helm repo add incubator http://storage.googleapis.com/kubernetes-charts-incubator helm install --name cord-kafka incubator/kafka
If you are experierencing problems with a multi instance installation of kafka, you can try to install a single instance of it:
helm install --name cord-kafka incubator/kafka -f examples/kafka-single.yaml