Short answer — two ways to read “most popular”:

• All‑time / most‑produced: Honda Super Cub (the single most‑produced motor vehicle ever — 100 million+ Super Cubs produced since 1958). (global.Honda)

• Right now (recent best‑sellers, 2024–early‑2025): the global market is dominated by small commuter bikes and scooters from Honda, Hero, Yamaha, Yadea, TVS and Bajaj. Honda is the biggest brand (roughly ~19–20 million two‑wheelers in 2024) followed by Hero and Yamaha; the top‑selling models in large markets recently have included Hero Splendor (India) and Honda Activa (scooter) along with popular commuter models such as the Honda CB/Shine family, Bajaj Pulsar/CT100 family and various Yamaha 125–155cc models. (motorcyclesdata.com, bikedekho.com, timesofindia.indiatimes.com)

More detail (concise list):

• Honda Super Cub — all‑time bestseller / most produced (iconic underbone; >100 million cumulative production as of 2017 milestone). (global.Honda)
• Hero Splendor (Splendor Plus family) — one of the world’s best‑selling commuter models in recent years, outselling many rivals in India (millions of units per year for the Splendor lineup). (bikedekho.com)
• Honda Activa — the most popular scooter in India (hundreds of thousands of units per month in 2023–2024; a major global-volume scooter for Honda). (timesofindia.indiatimes.com)
• Honda/Yamaha/TVS/Bajaj commuter models — these brands’ 125cc and 100–150cc commuter bikes (CB/Wave/Shine, YBR/NMAX family, Pulsar/CT100, TVS Jupiter, etc.) collectively make up the bulk of global unit sales in Asia/Latin America. (See global brand ranking/volume data.) (motorcyclesdata.com)
• BMW R 1300 GS / BMW GS family — example of a top seller within the premium/adventure segment (BMW reported record motorcycle sales in 2024 driven largely by its GS models). (motorcycle.com)

Quick note on interpretation: “Most popular” can mean (a) cumulative production (Super Cub clearly leads), (b) annual/monthly sales (brand‑level leaders: Honda, Hero, Yamaha; model leaders vary by country and timeframe), or (c) cultural/popularity (some classic models like Royal Enfield Classic, Harley Sportster, BMW GS are globally famous but sell far fewer units). The figures above use brand & model sales/production reported in 2024–early‑2025. (motorcyclesdata.com, global.Honda)

If you want, I can:

• Give a ranked list of the top 10 individual models by annual sales (by country or global, if available), or
• Show “most popular” by region (India, Southeast Asia, Europe, USA, Latin America), or
• Provide links to the source reports and exact unit numbers.