Ripping a 125cc two-stroke dirt bike is a blast. With some well-calculated mods, it can be even more fun. Here’s our feedback on this modified 2022 Yamaha YZ125.
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Dirt Rider was recently invited to spin some laps on Jay Clark’s latest project: an updated 2022 Yamaha YZ125. Set up for Jay himself, this was a personal project as more and more 125cc two-stroke races are popping up across Southern California. According to Jay, “We kept the mods somewhat simple.” With a list of contributors alphabetically ranging from Cometic Gaskets to Wiseco, we’ll let you be the judge of that!
Cahuilla Creek MX sits at approximately 3,500 feet of elevation and features everything from off-road trails to a kids track to a vet track and a proper main track. Not typically 125 territory, I was curious how much performance Jay would be able to squeeze out of Yamaha’s smallest displacement full-size motocross offering. Would it be main track worthy, or would a 180-pound pilot be relegated to spinning laps on the vet track only? Read on to learn more about the build and to hear some personal opinions on the state of 125s in general.
2022 Yamaha YZ125 Project Bike Engine
Most of our articles begin with a suspension piece, engine segment, chassis and ergonomics discussion, whilst wrapping up with our overall impressions. Since this is a 125 test, I feel the need to reverse that order a bit.
Engine performance is everything when discussing small-bore two-strokes, and the all-new 2022 YZ125 improved upon Yamaha’s long history of producing solid two-stroke machinery. In fact, unlike every other Japanese manufacturer, they haven’t missed one production year for two-strokes since 1974. As a longtime two-stroke rider, I appreciate the engine performance of the new platform over the 2021 and earlier predecessors. Longer revving with more meat through the midrange to top-end, it’s an experienced rider's dream machine.
With minimal investment, Jay was able to enhance the already-potent powerband. The addition of a Keihin carburetor for 2022 was a welcome change, but left something to be desired in stock configuration. Put simply, the standard jetting was off, so Jay went with a JD Jetting jet kit to resolve the issue. Tom Morgan Racing (TMR) was called in to inspect the cylinder and modify the head to run on VP Racing’s C12 race gas. Combined with Klotz Synthetic Lubricants R-50 premix and an FMF exhaust system, this YZinger was both one clean revving and one cleaning sounding machine.
Even though this project bike had minimal hours at the onset of the build, a fresh Racer Elite Piston Kit from Wiseco Performance Products provided ease of mind when revving it out for all its worth. Wiseco also provided the stronger CV4 radiator hoses and higher temperature radiator cap. Having a good clutch actuation is key on small-bores that still require riders to learn and use proper control, so Rekluse contributed a Core Manual TorqDrive assembly to the build.
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Dirt Rider was recently invited to spin some laps on Jay Clark’s latest project: an updated 2022 Yamaha YZ125. Set up for Jay himself, this was a personal project as more and more 125cc two-stroke races are popping up across Southern California. According to Jay, “We kept the mods somewhat simple.” With a list of contributors alphabetically ranging from Cometic Gaskets to Wiseco, we’ll let you be the judge of that!
Cahuilla Creek MX sits at approximately 3,500 feet of elevation and features everything from off-road trails to a kids track to a vet track and a proper main track. Not typically 125 territory, I was curious how much performance Jay would be able to squeeze out of Yamaha’s smallest displacement full-size motocross offering. Would it be main track worthy, or would a 180-pound pilot be relegated to spinning laps on the vet track only? Read on to learn more about the build and to hear some personal opinions on the state of 125s in general.
2022 Yamaha YZ125 Project Bike Engine
Most of our articles begin with a suspension piece, engine segment, chassis and ergonomics discussion, whilst wrapping up with our overall impressions. Since this is a 125 test, I feel the need to reverse that order a bit.
Engine performance is everything when discussing small-bore two-strokes, and the all-new 2022 YZ125 improved upon Yamaha’s long history of producing solid two-stroke machinery. In fact, unlike every other Japanese manufacturer, they haven’t missed one production year for two-strokes since 1974. As a longtime two-stroke rider, I appreciate the engine performance of the new platform over the 2021 and earlier predecessors. Longer revving with more meat through the midrange to top-end, it’s an experienced rider's dream machine.
With minimal investment, Jay was able to enhance the already-potent powerband. The addition of a Keihin carburetor for 2022 was a welcome change, but left something to be desired in stock configuration. Put simply, the standard jetting was off, so Jay went with a JD Jetting jet kit to resolve the issue. Tom Morgan Racing (TMR) was called in to inspect the cylinder and modify the head to run on VP Racing’s C12 race gas. Combined with Klotz Synthetic Lubricants R-50 premix and an FMF exhaust system, this YZinger was both one clean revving and one cleaning sounding machine.
Even though this project bike had minimal hours at the onset of the build, a fresh Racer Elite Piston Kit from Wiseco Performance Products provided ease of mind when revving it out for all its worth. Wiseco also provided the stronger CV4 radiator hoses and higher temperature radiator cap. Having a good clutch actuation is key on small-bores that still require riders to learn and use proper control, so Rekluse contributed a Core Manual TorqDrive assembly to the build.
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