Since its introduction in 2002, the Yamaha YZ85 has
remained relatively unchanged—except for small parts and
minor styling changes. Ten years later, the bike is almost
identical. Justin Hoeft is a top amateur racer with limited
support from Yamaha through Thousand Oaks Powersport
and also a Dirt Bike test consultant. Here is what was
done to Hoeft’s YZ85.
The engine received a complete GYTR 112cc big-bore
kit made by Athena. This complete kit includes a new
precision-made, stroked crankshaft and nickel-carbide-plated cylinder with enlarged water passages and
revised porting designed specifically for improved performance. The cylinder head is also designed with
enlarged water passages. The GYTR kit has everything
needed for a complete installation—except the required
crankcase machining. It includes a crankshaft, connecting rod, cylinder, cylinder head, precision-made piston
Justin Hoeft hams it up on his supermini.
with rings, clips, wrist pin, studs, nuts, O-rings, and gaskets (different-thickness base gaskets to adjust
squish). To help the bike breathe, we installed a GYTR
complete exhaust by FMF, a V-force reed valve, and a
dual-stage, high-flow air filter. A GYTR complete clutch
was also installed, which included a billet clutch basket,
billet clutch pressure plate, billet inner clutch hub and a
stock Yamaha clutch kit.
The chassis got major updates also. GYTR offers a complete Super Mini chassis kit that includes longer front and
rear brake lines, a longer rear swingarm, bushings, bearings, collars, oil seals and plugs. We topped it off with front
and rear GYTR wheels through Dubya USA utilizing Talon
hubs, spline-drive heavy-duty spokes and Excel rims.
With the major updates completed, Hoeft bolted on a
GYTR chain and sprocket kit and Tag bars, and Factory
Connection handled all the hard work in the suspension