From a driving experience, my favorite is x30. As a complete experience, it is the fullest and richest I have piloted. The way the engine responds and sounds is, hands down, my favorite. The feeling of being on the pipe in x30 is “special” and unique. It’s tactile, and your chest resonates along with the engine @ 15k+!
My second favorite is the Honda gx series of rental engines. They don’t sound like much, aren’t fast, but they are cheap and most importantly, work. It’s a reliable and effective little engine that always makes me smile. Most importantly, it’s never a pain in the butt.
I suspect that if I ever got my hands on one of Alan’s old school dd 100 I’d have a new favorite. I was watching Trulli? send it sideways into a pass and man, that sounds/looks good.
Silly thread, I know, but what’s your favorite? It’s not about which is “fastest”, it’s about which experience you enjoy most.
Not totally sure what my absolute favorite is but I did really enjoy the HPV/KPV/Komet with the “4” pipe. Pretty much gutless on the bottom end but really started screaming in the mid-range and top-end. It was a bit like driving a car stuck in 4th gear. Really emphasized smoothness on the low speed stuff and had enough power to chuck it around in the mid-range.
KA is really fun and objectively better as a package but it is almost too easy too drive. It has more torque on the bottom so doesn’t penalize mistakes as much and it’s more foolproof to tune. The HPV required more fiddling with the carb and was a bit more on edge.
No question ICA. I went to ICA from Yamaha Formula Y thinking it would not be too different just more power. It was. Where the FY ran out gas 16,500 or so, the ICA was just getting started. It scared the Pooh out of me the first time it went screaming past 16000 and pulled like a kicked mule up and past 19000. The sound was incredible and I thought there was no way it would stay together…but it did lap after lap.
I drove Rotax after that and it was totally different and required delicate throttle modulation. I did much better with the Rotax than in ICA, but Rotax had/has nowhere near the visceral appeal.
For an engine I can enjoy on a quiet practice day, have a challenge putting together a good qualifying lap, or have an exciting wheel-to-wheel race with, or have anyone in the pits who wants to try a kart go out - IAME X30.
For an engine that provides an absolutely wild ride, that requires you to be absolutely on your game, that both allows and requires great throttle and kart balance control, that makes the straightaways go psychedelic - TM KV95.
100cc rotary air-cooled with a slide carb, nothing like taking your hand off the wheel at the end of the straight pulling over 19000rpm to choke. Or the feeling of the motor pulling more revs after making it just a little bit leaner.
Such an awesome sound too, it’s not just the exhaust that makes the noise but the fins make them sing aswell. The air-cooled sound much better than the water-cooled.