1.Use Openiv and go to update\update.rpf\common\data\dlclist.xml and add this line below to the dlclist.xml

<Item>dlcpacks:\jawa\</Item>

2.Extract "jawa" from "dlcpacks",in update\x64\dlcpacks

You can spawn a car using trainer function "spawn by model name"
JAWA 350 - jawa

These bike were made by daemon1988 
This add-on was made by UrbVan