It isn’t a revolutionary year for KTM’s mini MXers. Regardless, there are still significant upgrades to the 2021 KTM youth motocross lineup, besides the updated graphics they all get. Let’s dive into this six-model line of motocross motorcycles for youngsters.
2021 KTM 85 SX 19”/16” and 17”/14”
The two big guns of the KTM youth motocross line are back with several upgrades. Brakes are the big news, with a new Formula braking system with a two-piston front caliper and single-piston rear. The pads are the same size as on adult KTM motocrossers, so there is a lot of surface area there. Plus, the rear disc is 10mm larger in diameter—up to 220mm—and it is bolted to a new hub. Additionally, there’s a new roller throttle and new throttle cable, adding to smoothness and reliability.
2021 KTM 65 SX
The mid-size mini from KTM gets a new WP Xact air-sprung fork and triple-clamp modification to grip it. The 35mm fork saves nine ounces compared to the previous fork. The 2021 KTM 65 SX also has a new tapered aluminum handlebar, with new ODI grips, plus a new roller throttle assembly with a cable to match.
2021 KTM 50 SX and 50 SX Mini
The two micro-minis have many common upgrades, those the list isn’t identical. Only the 2021 KTM 50 SX will have the new adjustable WP Xact shock with progressive damping. However, both get a new WP Xact 35mm air-spring fork that saves a few ounces, along with a triple clamp that has been modified to accommodate the new fork assembly. ODI lock-on grips are now standard on the 50s, and they have a smaller diameter than previous to make it easier for young hands to hold on. There’s also a new throttle assembly that is smoother due to roller actuation, and KTM has thrown in a new throttle cable to go along.
2021 KTM 50 SX-E 5
There is one change from the KTM 50 SX-E 5 we briefly tested last year—the new 35mm WP Xact air-spring fork. That drops nine ounces away from the front of the bike. Otherwise, the highly adjustable and adaptable KTM electric motocrosser is the same.
2021 KTM 85 SX 19”/16” (and 17”/14” Specs)
ENGINE
- Type: Single-cylinder two-stroke
- Displacement: 85cc
- Bore x stroke: 47 x 48.95mm
- Starting: Kick
- Lubrication: Premix 40:1
- Fueling: 28mm Mikuni PWK carburetor
- Transmission: 6-speed
- Clutch: Wet multi-disc w/ Formula hydraulics
CHASSIS
- Frame: Central double-cradle chromoly steel w/ aluminum subframe
- Handlebar: Tapered aluminum
- Front suspension; travel: Fully adjustable WP Xact inverted 43mm fork; 11.0 inches
- Rear suspension; travel: Linkage-Free fully adjustable WP Xact shock w/ PDS damping; 12.0 inches
- Wheels: Excel
- Front wheel: 19 x 1.60 (17”/14”: 17 x 1.40)
- Rear wheel: 16 x 1.85 (17”/14”: 14 x 1.60)
- Tires: Maxxis
- Front tire: 70/100 x 19 (17”/14”: 70/100 x 17)
- Rear tire: 90/100 x 16 (17”/14”: 90/100 x 14)
- Front brake: 240mm disc w/ floating Formula caliper
- Rear brake: 220mm disc w/ floating Formula caliper
DIMENSIONS and CAPACITIES
- Wheelbase: 50.8 inches (± 0.4 in)
- Rake: 24 degrees
- Triple clamp offset: 14mm
- Seat height: 35 inches (17”/14”: 34 inches)
- Ground clearance: 14.8 inches (17”/14”: 13.9 inches)
- Fuel capacity: 1.4 gallons
- Curb weight: 158 pounds (17”/14”: 156 pounds)
2021 KTM 65 SX Specs
ENGINE
- Type: Single-cylinder two-stroke
- Displacement: 65cc
- Bore x stroke: 45 x 40.8mm
- Starting: Kick
- Lubrication: Premix 60:1
- Fueling: 24mm Mikuni VM carburetor
- Transmission: 6-speed
- Clutch: Wet multi-disc w/ Formula hydraulics
CHASSIS
- Frame: Central double-cradle chromoly steel w/ aluminum subframe
- Handlebar: Tapered aluminum
- Front suspension; travel: Air-adjustable WP Xact inverted 35mm fork; 8.5 inches
- Rear suspension; travel: Linkage-free fully adjustable WP Xact shock w/ PDS damping; 10.6 inches
- Front wheel: 1.60 x 14
- Rear wheel: 1.60 x 12
- Tires: Maxxis
- Front tire: 60/100 x 14
- Rear tire: 80/100 x 12
- Front brake: 198mm disc
- Rear brake: 160mm disc
DIMENSIONS and CAPACITIES
- Wheelbase: 44.8 inches (± 0.4 in)
- Rake: 25.5 degrees
- Triple clamp offset: 22mm
- Seat height: 29.5 inches
- Ground clearance: 11 inches
- Fuel capacity: 3.7 quarts
- Curb weight: 123 pounds
2021 KTM 50 SX (and 50 SX Mini) Specs
ENGINE
- Type: Single-cylinder two-stroke
- Displacement: 49cc
- Bore x stroke: 39.5 x 40mm
- Starting: Kick
- Lubrication: Premix 60:1
- Fueling: 19mm Dell’Orto PHBG BS carburetor (50 SX Mini: 12mm Dell’Orto PVHA XS carburetor)
- Transmission: 1-speed
- Clutch: Fully automatic adjustable centrifugal
- Final drive: 1/2 x 3/16” chain
CHASSIS
- Frame: Central double-cradle chromoly steel
- Subframe: Steel
- Handlebar: Tapered aluminum
- Front suspension; travel: Air-adjustable WP Xact inverted 35mm fork; 8.1 inches (50 SX Mini: 3.9 inches)
- Rear suspension; travel: Linkage-free fully adjustable WP Xact shock w/ PDS damping; 7.3 inches (50 SX Mini: Linkage-free WP Xact shock 5.6 inches)
- Front wheel: 12 x 1.50 (50 SX Mini: 10 x 1.60)
- Rear wheel: 10 x 1.60
- Tires: Maxxis
- Front tire: 60/100 x 12 (50 SX Mini: 2.50 x 10)
- Rear tire: 2.75 x 10
- Front brake: 160mm disc
- Rear brake: 160mm disc
DIMENSIONS and CAPACITIES
- Wheelbase: 40.6 inches (± 0.4 in)
- Rake: 24 degrees (50 SX Mini: 23.6 degrees)
- Triple clamp offset: 22mm
- Seat height: 27 inches (22 inches)
- Ground clearance: 9.9 inches (7.2 inches)
- Fuel capacity: 2.4 quarts
- Curb weight: 95 pounds (50 SX Mini: 91 pounds)
2021 KTM SX-E 5 Specs
MOTOR
- Type: BLDC w/ outer rotor
- Maximum power: 6.7 horsepower @ 3200 rpm
- Maximum torque: 9.6 ft/lbs @ rpm
- Redline: 6000 rpm
- Transmission: Clutchless direct drive
- Final drive: 1/2” x 3/16” chain
BATTERY
- Type: KTM lithium-ion
- Capacity: 907 Wh
- Charger: 900 W
- Charge time to 100%: 70 minutes at 25 A
- Charge time to 80%: 45 minutes at 25 A
- Input: 110 V or 220 V
CHASSIS
- Chassis: Steel frame w/ aluminum swingarm
- Handlebar: Tapered aluminum
- Front suspension; travel: Fully adjustable WP Xact air-sprung 35mm inverted fork; 8.1 inches
- Rear suspension; travel: Fully adjustable WP Xact PDS piggyback-reservoir shock; 7.3 inches
- Rims: Aluminum
- Front wheel: 12 x 1.5
- Rear wheel: 10 x 1.6
- Tires: Maxxis Maxxcross SI
- Front tire: 60/100 x 12
- Rear tire: 2.75 x 10
- Front brake: 160mm disc
- Rear brake: 160mm disc
DIMENSIONS and CAPACITIES
- Wheelbase: 40.6 inches
- Rake: 24 degrees (22mm triple clamp offset)
- Seat height: 26.2 inches (adjustable)
- Curb weight: 90 pounds
