I was given this "free" bike that needed some work. So I have replaced the wheels (including replacing the broken coaster brake with a coaster/3 speed hub) I cleaned the heck out of it, replaced the chain and saddle. On my first ride the bottom bracket seized and the LBS did a clean and tune up, but I was warned that it isn't a real bottom bracket it is a built in POS. (I'm paraphrasing)

Today I went on my first post clean up ride and there is a clunking sound / feeling in the pedals at a certain point in each rotation. I have ruled out it being the pedals striking the chain guard or the kickstand. Also, it only clunks on the straight away but not uphill.

My questions are:

Is there anything quick and easy I can do to fix it?

I can't afford the cash to getting it professionally checked out this month, will I make it worse by riding it in the mean time?

Am I completely hooped? (AKA - the bike is on it's way to the great bike path in the sky)

Do I just have to learn to live with it?

Thank you for any help you can give me