4-stroke SOHC-2. It's basically 1/2 a SOHC-4. I got mine to learn wrenching without destroying my 550. So far, my performance is miserable, BUT, the fact she runs at all is a miracle - a major project bike in it's infancy. I'm ripping stuff off, cleaning & playing and slapping it back on. The more fun I have, the more I rip off. I fired it up the other day and spun around the block once just to prove it actually runs. Coughed, sputtered and puked gas. I obviously included the carbs with my experimentation and haven't even started to set them back up properly. Just a blind reassembly, bolt on & fire up. As I said, a miracle. I'm looking for a ridiculously high milage commuter - the fastest I need to go for my daily commute is about 45-50 mph. The power will never rival my 550, but should be plenty for a simple daily commuter. I view it as a scooter on steroids, with enough power to safely play in whatever traffic I face on my way back & forth to work. That said, I believe, at least in NYS, there is a minimum cc you need to tackle the interstates. Hell, I don't even like taking the 550 on them anyway, so I'd never even think of it on the 175. The secondary highways - blue highways {good book, by the way} are more fun & interesting anyway.
