STEPS To Remove Blog Name From Page Title :
1. Login, Go to Blogger setting, Layout, Edit HTML
2. Take a backup by clicking Download Template
3. Expand Widget Templates
4. Search for <title> and you will find following lines. Change them as suggested below:
Change From:
<title><data:blog.pageTitle/></title>
TO
<b:if cond='data:blog.pageType == "index"'>
<title><data:blog.title/></title>
<b:else/><title><data:blog.pageName/></title></b:if>
5. Click Save Template
However its result can be quickly seen in browser page tab but it will take some time to see effects in search results because search engine takes some time to effect changes.