Most 125cc engines we see are single-cylinder units in entry-level motorbikes, but what you see here is no ordinary 125. It’s a hand-crafted V10, with sequential fuel injection, dry-sump lubrication and a triple-plate clutch, and yes, it runs. It runs rather beautifully, in fact.
There’s an extensive build thread for the project, which is shown to span nearly three years, and include a substantial amount of machining. The attention to detail here is - as you’d expect - incredibly thorough.
If you had such a thing in your garage, what would you stick it in?