ORIGINAL: Jim D
From the YSPerformance website:
YS63 Weight 17.9 ounces, no weight listed for YS63S
YS63S 17.4 ounces
From Horizon website:
Saito 72 weight 16.6 ounces (with muffler)
Let's stick to published fact here.
Published fact doesn't mean squat. All you need to do is put both engines on the same micro precision postal scale.
Here is my YS 63S on a postal scale that measures up to 3 lbs:
I also put my Saito .72 on the same postal scale a while back (didn't have a digital camera back then), and it weighed 17.9 oz with muffler, muffler elbow, prop nuts, and prop washer. The same Saito .72 without muffler, elbow, prop washer, and prop nuts weighed 16.6 ounces. The weight listed on the website is the weight of the engine alone.