MIKE ALESSI’S 42-HORSEPOWER YAMAHA YZ134 TWO STROKE

Some found footage that we had misplaced of Mike Alessi’s XPR-tuned Yamaha YZ134. The idea for Mike Alessi to race more two-stroke races came after Mike raced the ESR-built Yamaha YZ325 two-stroke at the Monster Energy Cup in 2019. But, for most two-stroke racers, the 125 class is the high-profile prize to be sought after. Luckily for Mike, his personal 125 two-stroke revival was happening simultaneously with the boom of 125-only racing. Yes, Glen Helen’s World Two-Stroke Championship has been the premier two-stroke race since 2010, but Mike decided to set his eyes on more two-stroke racing in partial retirement, and for that he needed a YZ125 to pair with his ESR YZ325.

Chad Braun at XPR Motorsports helped turn Mike’s YZ125 into a YZ150, but both XPR and Mike felt that a Yamaha 150 would give up too much power on the top end, and they landed on 134cc for the race-engine spec. Chad made the cylinder 2mm bigger and upped the internal volume to 134 cubic centimeters. For fuel, Mike used VP MRX02 cut with VP C15. Finally, after learning all about the YZ134, it was time for the MXA test riders to hit the track. The first comments were, “It feels like a factory two-stroke with more bottom end,” and “This bike has a major personality and it wants you to go faster.” Alessi’s YZ134 pumped out 42.0 horsepower on the XPR’s dyno.