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return to shopFRP FX Series
Gas Dirt Bikes & Pit Bikes
for Kids, Teens & Adults
Three dirt bikes. 40cc to 140cc.
40cc, 125cc & 140cc gas dirt bikes — built to grow with the rider.
Top speed · FX40 20 · FX125 56 · FX140 65
Which FX dirt bike is yours?
40
Where it all starts
FX40 Ogemaw
Twist the throttle. Go.
Shopping for a kids dirt bike, or a first dirt bike for a 6–12 year old? The FX40 Ogemaw is a 40cc four-stroke built for first-timers — no oil to mix, no gears to think about. Full front and rear suspension soaks up the rough stuff, dual disc brakes stop on command, and the 20 mph top speed keeps first rides confidence-building. Carries riders up to 132 lb — the bike a kid learns on and never forgets.
40cc 4-Stroke20 mphFull SuspensionDual Disc BrakesNo Oil Mixing132 lbAges 6–12
Shop FX40
From$279.99
Red
See the FX40 ride
125
Where shifting begins
FX125
The first clutch you actually pull.
Looking for a 125cc dirt bike for a teenager — or a 125cc pit bike with a real clutch? A genuine 4-speed manual and wet multi-plate clutch turn a rider into a real rider — shifting, feathering, launching. The proven Zongshen® 125cc air-cooled engine keeps pulling up the steep stuff, two wheel sizes fit a growing teen or a full-grown adult, and front and rear hydraulic discs haul it all back down. This is the bike dirt-riding skills are built on.
Zongshen® 125cc Air-Cooled8.8 hp4-Speed ManualWet Clutch2 Wheel Sizes28–34" Seat265 lb
Shop FX125
From$799.99
White
See the FX125 ride
140
Where you stop holding back
FX140
For the rider who's done learning.
Want a fast 140cc dirt bike for a teen or an adult who’s done learning? The FX140 steps up to a 140cc oil-cooled four-stroke with strong low-end torque and a ~65 mph (105 km/h) top end — paired with a 4-speed manual clutch, chain drive and hydraulic disc brakes. A taller ~33.9-inch seat and more bike underneath, built for experienced teens and adults who’ve outgrown a first dirt bike and want real trail speed.
140cc Oil-Cooled~65 mph Top Speed4-Speed Manual ClutchHydraulic Disc BrakesElectric + Kick Start17"/14"
Shop FX140
From$1,149.99
Red
See the FX140 ride
Side by side
Pick the right bike.
Swipe to compare →
| FX140New | FX125New | FX40Starter | |
|---|---|---|---|
 |  |  | |
| Best for | Riding for real | Learning to shift | Learning to ride |
| Rider | Teens & adults | Teens & adults | Kids 6–12 |
| Engine | 140cc oil-cooled | 125cc air-cooled | 40cc 4-stroke |
| Top speed | ~65 mph | ~56 mph | 20 mph |
| Transmission | 4-speed manual | 4-speed manual | Automatic |
| Brakes | Hydraulic disc | Hydraulic disc | Dual disc |
| Suspension | Front & rear | Front & rear | Full F & R |
| Start | Electric + kick | Electric + kick | Easy pull start |
| Wheels | 17"/14" | 14"/12" or 17"/14" | Mini |
| Max load | 265 lb | 265 lb | 132 lb |
| Price | From $1,149.99 | From $799.99 | From $279.99 |
Questions, answered
Before you buy.
How fast is a 125cc dirt bike?
The FX125 tops out around 56 mph and the FX140 hits about 65 mph — real speed depends on rider weight, gearing and terrain. More on how cc translates to top speed.
What size dirt bike for a 12 year old?
Around 12, most riders fit the FX125 in the smaller 14"/12" size (28.1" seat). Match height and inseam with our dirt bike size chart by age, or see the best dirt bikes for 12-year-olds.
What’s the weight limit on a dirt bike?
The FX125 and FX140 both hold up to 265 lb, so they carry teens through adults; the FX40 is rated to 132 lb. Full breakdown of dirt bike weight limits.
FX125 vs FX140 — which should I choose?
Choose the FX125 (air-cooled, ~56 mph, two wheel sizes) if the rider is still learning to shift; choose the FX140 (oil-cooled, 65 mph, taller ~33.9" seat) once they’ve outgrown a first bike. We break it down in the 125cc vs 140cc dirt bike guide.
What size dirt bike for a teenager?
A taller teen fits the FX125 in the 17"/14" build (33.9" seat) or steps up to the FX140. See what size dirt bike for a teenager.
Are FRP dirt bikes street legal?
No — FRP dirt bikes are EPA off-road models, not registered for public roads. Ride them on private property, trails and off-road areas (the FX40 and FX140 are not sold in California). More on whether a dirt bike is street legal.
Do FRP dirt bikes need 2-stroke oil mixing?
No — every FRP FX is a four-stroke, so there is no fuel-and-oil premixing. See how to choose the right engine oil.
Trusted by 865+ verified buyers
Built around what riders ask.
A Zongshen® engine, not a no-name
The FX125 runs a Zongshen four-stroke — built by one of the world's oldest and largest engine makers. Decades of proven reliability, parts everywhere, and far fewer breakdowns than the no-brand engines in cheaper bikes.
Holds real weight
The question buyers ask most is how much a bike can carry. The FX125 is built for a 265 lb max load — so it fits a growing teen or a full-grown adult, not just a small kid.
Fits the rider
The other thing everyone asks: will it fit? The FX125 comes in two wheel sizes with a 28–34" seat, so one bike suits a younger rider or a taller adult — and the FX40 starts the little ones safely at 20 mph.
Grow with the rider
Start the journey
Pick the step that fits today. The next one will be waiting when they're ready.
