I am new to post and would appreciate help, so bought this Yamaha Dt 250 C model year 1976 and no spark at all took magneto apart and found a few issues with the wiring on the coils, the  condenser  and contacts are wired in series together. Cant find a proper wiring diagram of how they are wired, please

 

With no spark issues I always start at the most basic things first, check the spark plug, plug cap, coil, points and so on.  You didn’t mention that you checked these things is why I mention them 

I'm a little curious how you know that you "found a few issues with the wiring on the coils, the  condenser  and contacts are wired in series together." When you don't have a diagram?

Because what you're saying about the way it's wired sounds pretty correct to me.  Could it be possible you don't understand how the system works?

I'm not aware of anything but a basic generic ignition diagram in almost all the older service manuals in the Tech Library.  You might see if you can reach out to member DEET as he's rebuilt a lot of magnetos and might be able to answer questions. 

That said, no spark on the points magnetos is almost always something simple like cleaning the points, sometimes a bad condenser but I avoid changing that unless needed as new condensers sometimes suck these days. 

The only real exception I've come across to the "something simple" rule Oldbikenut mentioned is if there is physical damage...  but that's usually pretty obvious. 

condenser and points are, or should be in parallel

i.e. condenser "shorts" points

In an electrical sense, technically it's correct that the single wire condenser itself is in parallel with the points when condenser case is grounded.   

From a "visual" sense, most people in my experience will call the magneto ignition wiring "in series" as the "power" wire goes from stator windings to condenser to points like a daisy chain of components wired in series.