Derbi Variant Piston Port Specifications

Engine

Specifications

• Stroke: 43mm
• Bore: 38mm
• Displacement: 48.7cc
• Compression 8.5:1
• Rotation: CCW Facing Magneto

Transmission Oil

• Capacity is 400cc (fill to the fill hole located under the pedal shaft)
• SAE 80 EP (hard to find, do not use 80/90 that is gear oil)
• SAE 20W50

Main Bearings

• 17x40x12mm - 6203
• 17x47x14mm - 6303

Main Seals

• 17x28x6mm - Qty2

Case Bearings

• 25x52x15mm - 6205
• 15x42x13mm - 6302 (Watch out for cheap 6302 bearings, some come 16x42x13mm)

Case Seals

• 16x24x4mm - Qty2
• 15x30x7mm
• 25x40x7mm

Carburetor

Stock Type

• Dellorto 12/12

Jet Size

• ? (probably somewhere in the 50s)

Ignition

Specifications

• Motoplat
• 6V 12-15W

Timing Advance

• 1.8mm Before TDC (21 Degrees)

Point Gap

• 0.35mm to 0.4mm

Spark Plug

• NGK B7HS
• Champion L82

Lighting

Bulbs

• Headligh 6V 21W BA15s (1156)
• Taillight 6V 5W BA15s (67)
• Stoplight 6V 10W BA15s (67)
• Speedo 6V 1.5W BA7s (3898)

Wiring

Drivetrain

Belt

• Dayco 8004

Variator Weights

• 19.6mm x 14.375mm 10.5 Grams - Qty3

Chain

• 415 Size
• ? Links

Standard Front Sprocket

• 20T

Standard Rear Sprocket

• 30T

Variant Frame

Rear Shocks

• 302mm Length

Headset Bearings

• 3/16" loose ball bearings - Qty46
• Bearing Services part #STL-3/16GR25

Spoked Wheel Bearings

• 12x32x10mm - 6201-2RS - Qty4

Spoked Wheel Brake Pads

• 105x20mm - Qty2
• Tomos pads could fit with modification

Tires

• 2.25" x 17"

Axle Size

• 12mm