"No bicycle are allowed", what type of error is this?
This is a good question. The sentence, "No bicycle are allowed," is grammatically incorrect as you state. The reason for this is because the subject does not match the verb.
The principle is that subjects and verbs must match in number. This basically means that if a subject is singular, then the verb must be singular as well. If the subject is plural, then the verb must be plural as well.
So, the sentence should read: "Bicycles are not allowed." If you want to keep the subject singular, then it should read: A Bicycle is not allowed."
The key to remember that subjects and verbs must match in number.