Had 5100 5105 closed port and 510 open. Fine cutting saws but seen issues. So I stay away from them myself.So how do you feel about the Makita 50cc saw (s). They still can be had new in the box. Your thread here is two non strato closed port saws. Seems the Makita one and some earlier grey market Stihl ones fall in this category.
Seemed heavier too.
But cut right with my other 50cc saws tested with 3/8.
510 weight PHO dry with 4910 346