Last year I purchase an inexpensive Raptor Petcock on Ebay and now at highway speeds, I have fuel starvation situation.  I assume the fuel flow is restricted.  What is a good petcock to purchase and model number.

A Genuine Raptor petcock. Just go to the local dealer. No waiting, no freight, no cheap knockoff.
Now, IF, when it was new, it didn't starve, then the filter screen may be plugging up.
Try it on reserve. If it's different,,,,, then you have a clue.
Have you added an inline filter?

Thanks for the input.  I have ordered a new Yamaha Petcock which should solve my problem.