| Tbh imo chains snap for one reason mostly - poor maintenance or mal-adjustment. I know sometimes you get batches of bad chains but.....
I've seen some shocking examples of chain maintenance.
My Sprint RS chain is 3 years & 15k miles old, it has been adjusted twice. The one of my VFR750 went to 30k miles in 7 years with no more than a couple of adjustments as well.
Asides from oil/filter changes it's one of the most important maintenance items and one of the easiest to fug up. Putting small 14t gearbox sprockets on stresses them as well - best stick to 15t and go up on the rear sprocket instead if you want to gear the bike down. | 
Threaded Mode