Are the sentences correct?

I do not know what the problem with my motorcycle is.

Is the above sentence also correct?

tanguatlay wrote:

I do not know what the problem with my motorcycle is.

Is the above sentence also correct?

Strictly, the verb 'is' goes after the subject, which is the problem, not the motorcycle. However, you will encounter the informal/casual form you have quoted.

The first. It is an indirect question, or statement of lack of knowledge in which the verb 'to be' ('is') comes after the subject (the knowledge sought or lacking).

Direct question:
What is the problem with my motorcycle?
Where are my glasses?
Who is that man who is looking at me?
What is the purpose of life?

Indirect question, or statement of lack of knowledge:
I do not know what the problem is with my motorcycle.
I do not know where my glasses are.
I do not know who that man is who is looking at me.
I do not know what the purpose of life is.