The Bike Hub

Every bike on the gate.
Spec it. Set it up. Ride it.

Real specs for the dirt bikes and ATVs Midwest racers ride — engine and class details, maintenance schedules, terrain-matched setup, and the parts that fit, all on one page. Pick your class by age below, then open any bike for the full rundown.

Pick your class by age

General amateur guidance — local club rules vary

50cc

Ages 4–8

50cc 2-stroke (auto)

The first race bike — automatic clutch, no shifting. This is where most racers start.

65cc

Ages 7–11

65cc 2-stroke

First bike with a clutch and gears. The real introduction to shifting and racing lines.

85cc

Ages 9–15

85cc 2-stroke

Faster, taller minis. Big-wheel versions bridge the gap toward supermini.

Supermini

Ages 12–16

85–112cc 2-stroke / up to 150cc 4-stroke

The hottest mini class — bigger bore and wheels right before moving to full-size.

125 / 250F (amateur)

Ages 12+

125cc 2-stroke or 250cc 4-stroke

The jump to full-size bikes. A 125 two-stroke or a 250 four-stroke — the core amateur classes.

250F / 450 (pro / open)

Ages 16+

250–450cc 4-stroke

Premier amateur and pro classes. The 450 is the top of the sport.

The catalog

Yamaha

YZ65

Motocross

Mini (65)

Liquid-cooled 65cc two-stroke mini racer — the step up from 50s for the 7–10 class.

65cc·2-stroke·Liquid-cooled

YZ85

Motocross

Mini (85)

Classic 85 two-stroke — the proving ground for the supermini ranks.

85cc·2-stroke·Liquid-cooled

YZ125

Motocross

125 2-stroke

The benchmark 125 two-stroke — light, revvy and a rider favorite for fun and 125 classes.

125cc·2-stroke·Liquid-cooled

YZ250

Motocross

250 2-stroke

Big-bore two-stroke MX bike — torquey, simple to maintain, beloved in 250 2T classes.

249cc·2-stroke·Liquid-cooled

YZ250F

Motocross

250F

250 four-stroke MX workhorse — strong power and the app-tunable engine that defined the class.

250cc·4-stroke·Liquid-cooled

YZ450F

Motocross

450

450 four-stroke MX flagship — big, smooth power with Yamaha Power Tuner app mapping.

450cc·4-stroke·Liquid-cooled

YZ250FX

Off-Road / Cross-Country

250F off-road

Off-road 250F — wide-ratio gearbox, kickstand and tank for GNCC/hare scramble.

250cc·4-stroke·Liquid-cooled

PW50

Trail / Youth

First bike

The legendary shaft-drive 50 trainer — no chain, adjustable throttle stop, the classic very first bike.

49cc·2-stroke·Air-cooled

TT-R50E

Trail / Youth

First bike

Electric-start air-cooled 50 four-stroke trainer with a three-speed auto-clutch gearbox.

49cc·4-stroke·Air-cooled

TT-R110E

Trail / Youth

Youth trail

Electric-start 110 trail four-stroke — the easy step up once a 50 gets small.

110cc·4-stroke·Air-cooled

TT-R125

Trail / Youth

Youth trail

Air-cooled 125 trail four-stroke with manual clutch — big-wheel LE option bridges toward full size.

124cc·4-stroke·Air-cooled

YFZ450R

Sport ATV

450 ATV

YFZ450R — the benchmark race quad, 450 four-stroke.

449cc·4-stroke·Liquid-cooled

Brand popularity reflects how many riders in our own race-results database are recorded on each make — an honest community signal, not manufacturer retail or registration sales data (which is proprietary). Our results sources record the bike make, not the model, so counts are brand-level. Specs shown are the figures we can verify; details we can’t confirm are left blank rather than guessed. Part links are Amazon searches for your model; MWR earns a small commission at no extra cost to you.