Two-Stroke vs. Four-Stroke: Built YZ125 vs. Stock YZ250F 11

Stock vs. stock, a 125 two-stroke is typically outshined by a 250 four-stroke. But what about a built up 125 vs. a stock 250F? The results are in so take a look!


By no means is this a definitive answer to the age old question of 2v4, but since we had this 2019 Yamaha YZ125 built up for Jake Weimer, who never got to race it because he got hurt, we decided to put it head to head with a stock YZ250F. 

2019 Yamaha YZ125 Parts List

  • Pro Circuit Suspension work
  • Pro Circuit Head and cylinder work
  • Pro Circuit Platinum Pipe
  • Pro Circuit Ti-2 Silencer
  • Pro Circuit Linkage Arm 
  • Moto Tassinari VForce Reed Valve

Ping's Fastest Lap Times (Fox Raceway Main Track)

  • YZ125 = 1.29.9 (0.5 seconds faster)
  • YZ250 = 1.30.4

Klinger's Fastest Lap Times (Fox Raceway Vet Track)

  • YZ125 = 1.58.4
  • YZ250 = 1.55.4 (3 seconds faster)


Going into this test, we expected both of us to be faster on the 250F and have more fun on the YZ125. At the end of the day, one of our hypotheses was proven right - we both had a blast on the YZ125. But the other was half wrong since Ping was just a half second faster on the YZ125 than the 250F. And to be fully transparent, he rode the YZ125 first, when the track was better. Plus, I think it is fair to say that his personal racing experience with a 125 two-stroke allows him to ride that bike to its full potential. Either way, for those of you thinking "Sure, I'll have fun on a 125 but I'll be slower than all my buddies," that just might not be the case!


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