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John Mulvihill

If you really want to go the Piston Port route under the current rules, I’d look at a pair of K71’s (AKA KPV, HPV).

Better quality than a Yamaha KT100.  Not much more expensive to rebuild.  Still uses a Walbro WB3a so tuning is similar.  Each motor is about 5 pounds heavier than a Yamaha. And 3-5 more HP each.

Under current engine rules the K71 is very close to a Comer P51.

Since the TaG 125’s came in, there are a lot of K71’s available used.  I bought 4 for under a grand.