Proper title template for post type

Hi,
I am currently using %%title%% as title template for the post types. I was thinking of changing it to %%title%% | %%sitename%%
Because the main keyword for my website is the name of the website and every post is related to that keyword.
So what do you suggest?
Also, will that affect SERP and current SEO performance or it will be beneficial.
PS. My site is relatively new.