Two Fibonacci functions
I don't like how you have all your logic in the header file.  You should declare your methods and fields in the header and use the .cpp file for logic.

On the other hand, C++ is not strictly object oriented, the way C# and Java are.  You didn't need a class for this solution, you could just have called fibHelper() from main().

Third point is your naming.  fibHelper() actually isn't a helper function, it is the function that actually calculates the Fibonacci sequence.  fibR() actually isn't recursive, like your comment says, it calls the recursive function.  int x1 doesn't say what it actually does, although it is easy to guess because the program is only a couple lines long - in a large project, this could (and probably would) cause many weeks of time wasted catching bugs.

Fourth is consistency:


static int fibR(int limit = 1000)
static int fibSumEven(int limit=1000)



For the most part, you are consistent, and I like how you use spaces around your operators and braces on your one-line ifs.