Moped Army

Working on a ZA50 for the first time (for my friend). It was not running when he bought it. It came with a 70cc TCCD kit which needed a new ring. It runs now but its lean, even with a 90, full rich, in the 15 mm Bing. I was expecting it to be more in the mid 80's but can't find a leak, should i try to replace the seals, and pucks while I'm at it? I can replace the seals from the outside like an E50 right? was my expected range just plane wrong? Thanks in advance.