How to remove SharePoint 2013 top navigation
Search for: id="DeltaTopNavigation"
Then remove below section.
<SharePoint:AjaxDelta id="DeltaTopNavigation" BlockElement="true" CssClass="ms-displayInline ms-core-navigation" role="navigation" runat="server">
<SharePoint:DelegateControl runat="server" ControlId="TopNavigationDataSource" Id="topNavigationDelegate">
<template_controls>
<asp:SiteMapDataSource
ShowStartingNode="False"
SiteMapProvider="SPNavigationProvider"
id="topSiteMap"
runat="server"
StartingNodeUrl="sid:1002"/>
</template_controls>
</SharePoint:DelegateControl>
<asp:ContentPlaceHolder ID="PlaceHolderTopNavBar" runat="server">
<SharePoint:AspMenu
ID="TopNavigationMenu"
Runat="server"
EnableViewState="false"
DataSourceID="topSiteMap"
AccessKey="<%$Resources:wss,navigation_accesskey%>"
UseSimpleRendering="true"
UseSeparateCss="false"
Orientation="Horizontal"
StaticDisplayLevels="2"
AdjustForShowStartingNode="true"
MaximumDynamicDisplayLevels="2"
SkipLinkText="" />
</asp:ContentPlaceHolder>
</SharePoint:AjaxDelta>--%>
<SharePoint:DelegateControl runat="server" ControlId="TopNavigationDataSource" Id="topNavigationDelegate">
<template_controls>
<asp:SiteMapDataSource
ShowStartingNode="False"
SiteMapProvider="SPNavigationProvider"
id="topSiteMap"
runat="server"
StartingNodeUrl="sid:1002"/>
</template_controls>
</SharePoint:DelegateControl>
<asp:ContentPlaceHolder ID="PlaceHolderTopNavBar" runat="server">
<SharePoint:AspMenu
ID="TopNavigationMenu"
Runat="server"
EnableViewState="false"
DataSourceID="topSiteMap"
AccessKey="<%$Resources:wss,navigation_accesskey%>"
UseSimpleRendering="true"
UseSeparateCss="false"
Orientation="Horizontal"
StaticDisplayLevels="2"
AdjustForShowStartingNode="true"
MaximumDynamicDisplayLevels="2"
SkipLinkText="" />
</asp:ContentPlaceHolder>
</SharePoint:AjaxDelta>--%>