Bicikl je ovdje, no skup je.

Because there are really two mini-statements joined together:

• Bicikl je ovdje = The bicycle is here
• skup je = it is expensive

In Croatian, je is the 3rd person singular form of biti (to be), so each clause needs its own form of the verb.

Croatian often omits the subject pronoun when it is understood, so skup je literally looks like expensive is, but it means it is expensive.

Also, Croatian clitics like je often take second position in their clause, which is why skup je sounds natural.

Because bicikl is a masculine singular noun, and the correct short-form adjective is skup.

Here is the agreement:

• masculine singular: skup
• feminine singular: skupa
• neuter singular: skupo
• masculine plural: skupi

So:

• Bicikl je skup. = The bicycle is expensive.
• Knjiga je skupa. = The book is expensive.

In your sentence, skup je is just a reordered version of je skup.

Because it is being used as a predicate adjective, not directly before the noun.

Compare:

• skup bicikl = an expensive bicycle
  
  • adjective directly describes the noun
• Bicikl je skup = The bicycle is expensive
  
  • adjective comes after the verb to be

In Bicikl je ovdje, no skup je, skup describes bicikl, even though the noun is not repeated in the second clause.

Here, no means but.

So:

• Bicikl je ovdje, no skup je = The bicycle is here, but it is expensive

In Croatian, no is a conjunction used to contrast two ideas. It is often a bit more bookish, formal, or stylistic than ali, which is the most common everyday word for but.

So these are both possible:

• Bicikl je ovdje, no skup je.
• Bicikl je ovdje, ali skup je.

They mean basically the same thing.

Most learners will hear ali more often in everyday speech.

• ali = the usual everyday but
• no = also correct, but often sounds a little more literary, formal, or emphatic

So in conversation, many speakers would more naturally say:

• Bicikl je ovdje, ali skup je.

But no is absolutely normal Croatian and worth knowing.

Because Croatian does not have articles like English a/an/the.

So bicikl can mean:

• a bicycle
• the bicycle

The exact meaning depends on context.

In your sentence, English naturally uses the bicycle, but Croatian just says bicikl.

It is in the nominative singular.

Why? Because bicikl is the subject of the sentence:

• Bicikl je ovdje = The bicycle is here

The basic dictionary form is also bicikl, so this is the form you would expect for the subject.

Both are possible, but skup je fits Croatian clitic word order well in this sentence.

The verb form je is a clitic, and clitics usually go in second position in their clause. In the clause skup je, the first element is skup, so je comes right after it.

You may also hear:

• Bicikl je ovdje, no je skup.

But that version sounds less natural in standard usage because clitics usually do not like to stand first in a clause after a conjunction in that way.

A very natural alternative is simply:

• Bicikl je ovdje, no skup je.
• Bicikl je ovdje, ali je skup.

Croatian word order is flexible, but not random.

Yes. In fact, ali je skup may sound more familiar to many learners because it mirrors the structure but it is expensive more closely.

For example:

• Bicikl je ovdje, ali je skup.

That is perfectly natural.

The version with no skup je is also correct, just a bit more stylistically marked.

Both can mean here, but there is a small nuance:

• ovdje = here, often a bit more explicit or precise
• tu = here / there, depending on context, often very common in speech

In many situations, they can both work:

• Bicikl je ovdje.
• Bicikl je tu.

For a learner, it is enough to know that ovdje definitely means here, while tu is also very common and slightly broader in use.

A rough pronunciation guide is:

• Bicikl ≈ BEE-tsee-kl
• je ≈ yeh
• ovdje ≈ OV-dyeh
• no ≈ noh
• skup ≈ skoop

A few helpful notes:

• j in Croatian is like English y in yes
• dj in ovdje sounds somewhat like a softened dy
• u is like oo in food

So the whole sentence sounds roughly like:

BEE-tsee-kl yeh OV-dyeh, noh skoohp yeh

In standard Croatian, that would normally sound incomplete. The second clause still needs the verb:

• Bicikl je ovdje, no skup je.

Croatian can omit pronouns, but not the necessary finite verb here.

So you can omit on (it/he), but not je.

Yes, it is grammatical and understandable.

That said, depending on style, many speakers might say one of these more everyday-sounding versions:

• Bicikl je ovdje, ali je skup.
• Bicikl je ovdje, ali skup je.
• Bicikl je ovdje, ali skup. — this last one is more colloquial and less complete-sounding

Your original sentence is correct, especially if the goal is to show:

• ovdje = here
• no = but
• skup = expensive