BUILDING A YAMAHA YZ85 BIG WHEEL FOR A GROWING KID

By Jason McCune

Moto? Off-road? Desert? My kid likes it all, so I wanted to build him something that had room for him to grow into, both physically and talent-wise. We all know how fast kids grow, and no one wants to be buying new bikes to keep up with growth spurts. We picked a 2022 Yamaha YZ85LW as our platform. The bigger 19-inch front and 16-inch rear wheels gave my son, Gavin, the room we were looking for so that he could literally grow into the bike.

THERE WAS NOTHING SUPER EXOTIC ON OUR WISH LIST—JUST THE TRIED AND TRUSTED MODS THAT MOST
PEOPLE MAKE TO THEIR BIKES. 

At 14 years old, Gavin is on the smaller side (more of a Ricky Carmichael stature). We had to make some modifications to the controls, suspension and ride height of the bike to fit his needs initially.

Because Gavin enjoys all types of riding, we wanted to build something that could cross over easily into motocross, desert riding and off-road racing. There was nothing super exotic on our wish list—just the tried and trusted mods that most people make to their bikes. We enlisted the help of some of our favorite brands to put all the details into making the bike fit his needs. 

We started with the Yamaha YZ85 because it has a good powerplant that needed some extra help. We wanted to add a little hit off the bottom, so we added an FMF Fatty pipe and a Turbinecore 2 silencer. The silencer has a built-in spark arrestor, so he’s legal when exploring the desert with his buddies. We also swapped out the stock reed cage for a Boyesen Rad valve. This helped keep the throttle crisp and clean. We also couldn’t resist the urge to outfit the YZ85 with Boyesen Factory Racing covers for that factory look. 

We went with a low-bend ODI bar because Gavin is on the smaller side. The ODI Podium Flight handlebars were the perfect addition once we added ODI MX-V2 lock-on grips. These are the ultimate must-have on any off-road motorcycle these days.

The off-road side of Gavin wanted added protection from what the desert and off-road elements dish out. In the past, we’ve struggled to get handguards on his smaller bikes. Now that he’s on an 85, there’s more room on the bars to get this done. We doubled up on products from SXSlideplate. We used their Burly handguards and their original skid plate that covers the rear linkage. This helps him slide right over those bigger obstacles in the off-road world. 

ProX replaced the stock gearing with their sprockets and chain. We went up one tooth on the rear to a 52 to help in the tight off-road riding that he likes to do. We capped that off by adding Dunlop rubber to get him some good traction! The boys at Throttle Syndicate provided the icing on the cake by helping make Gavin’s ride look even better than we hoped.

Some small setup details we did were to raise the forks 10mm up in the clamps and set the sag at 120mm, so the ride height was a little closer to the ground. Gavin feels that he has more control now since he can put his feet firmly on the ground. We all know how fast kids can grow, so we’ll revisit the whole process on a YZ125 in a couple of years!

 

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