If Barik is running One Man's Scrap on a high level try to use CC (To prevent Barik destroying them himself) and avoid the turrets to prevent this form of healing.
Unless the enemy Barik is using the Fortify Legendary card, his Barricade only has 5000 Health. It can sometimes be more advantageous to simply destroy the Barricade instead of sidestepping it.
Barik's primary shot is joke from far away, use this to your advantage and force the Barik to either stay in place and try to wait for help or go after you. Be ready for both of these options.
Remember to get rid of enemy deployables especially Barik's turrets and even more when he has the turret legendary card. They are not something to be ignored because when they are you don't realize when you are getting damaged
Tinkerin' Barik has range slightly beyond the level of Viktor. Don't even bother 1v1ing him if he even has 1 turret up, as he then requires multiple people focus firing him to bring him down.