I'd keep the balancer in because the cases wouldn't get any smaller, and why buzz more when revving out? A balancer is worth the little bit of added weight. The typical Chinese Honda-copy engine is single overhead cam, not push rod. If there was a simple push-rod 4-stroke single engine that was minimalist, compact, light, and had a great clutch and the right gear ratios, I'd be all over it. Four stroke simplifies the exhaust, so packaging for a custom frame is easier. But all those small four strokes tend to be on the chunky side. I've never weighed one. Anyone weighed a Honda 200 engine? And when it comes to air cooled, I'd rather have a 2 stroke. The air-cooled 4 strokes tend to run SO hot, and super heated engine oil negatively affects clutch performance and precludes use of gear-clutch-specific oils in models that share the oil with the clutch - which is the case with pretty much every smaller-size engine.