Yes and no. as you're probably aware, Bandit is still making 65 today and it comes with 38 HP Vanguard. So, a 23 hp engine on a machine that can handle 38 hp is underpowered by design.So the original engine ran properly for you at some point? If it was falling apart, of course it would seem underpowered. I'm sure Bandit didn't design them to roll off the assembly line running slow and not lasting. A brand new factory spec engine, should give you factory spec results, especially on a machine with low hours, as you stated yours was when you bought it.