The word order Indefinite_Article Noun is allowed in the unmarked case, that is, in stylistically unmarked contexts with no special focus on any of the constituents.

<br><br><b>English:</b> The English setting for this property is 'Yes'. The order <i>a bike</i> is neutral. 

<br><br><b>Note:</b> An indefinite article is opposed syntactically, morphologically and semantically to an definite article. 