DEXTER RACING Item number: DEXMB32PK
DEXTER RACING

Advantages at a glance

Early torque, wide band - fourth gear with full thrust
Optics close to standard, reduced noise level (quieter than Proma)
Installation without frame work, tires 3.00-10 and 90/90-10 compatible
279,00 €*
available immediately
Shipping weight 2,55 kg

Dexter Racing × W1R "Classic/Modern Box 3.0" - Smallframe exhaust Ø28 / Ø32 (50-144 cc)

Box system from the collaboration with W1R. Character: early, rich torque like a classic "banana exhaust", with higher revs and better peak power. Two variants with a targeted application range: Ø28 mm for short-stroke 75-112/115-130 cc setups, Ø32 mm for 133 cc and larger.

Ø28 / Ø32 manifold 43 / 51 mm stroke PK / HP Plug-and-Play 3.00-10 / 90/90-10

Characteristics

Box with early pressure build-up, stable revving
More peak power and speed reserve compared to classic bananas
Pleasant noise, near-standard external appearance

Technical data and variants

Manifold: Ø28 mm or Ø32 mm
Stroke: 43 mm and 51 mm
Mounting: one-piece, directly on the cylinder; PK/HP without modification
Partition wall: remains mounted
Tires: 3.00-10 or 90/90-10

Which version when? Ø28 mm vs. Ø32 mm

Ø28 mm - short-stroke and powerful for everyday use

Classic short-stroke setups 75-102 cc and medium-volume 115-130 cc
Rotary valve or diaphragm carburetor with moderate cross-sections
Focus on early torque, clean pulling power and good shift connection behavior
Recommended for conventionally stepped road transmissions (without short 4-speed)

Ø32 mm - large volume and high revving

≥133 cc, performance-oriented setups with higher throughput
Cylinder with larger exhaust cross-section, higher timing, large carburetor
More peak power and rev reserve, still good 4th gear connection
Also suitable for everyday use if the peripherals are matched to the larger cross-section

Note: On conventional setups, revs above 9 000 /min are realistic. The final choice depends on cylinder porting, carburetor size and desired characteristics.

Compatible vehicle models (selection)

PK 50/75/100/125 S
PK 50/125 XL, PK 50/125 XL2
PK 125 ETS, PK HP / FL2

Not suitable: PK "Automatica" (different engine/exhaust flow).

PK 50 XL / PK 50 XL2
PK 75 S / PK 75 Junior / PK 75 XL / PK 75 XL2
PK 125 S / PK 125 XL / PK 125 XL2

Requirement: Shift smallframe engine; no Automatica variants.

Fitting instructions

One-piece installation directly on the cylinder; PK/HP without frame work
Adjust carburetor tuning; typically increase main jet slightly on standard models
Check clearance for special rims/brakes
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