Crankshaft
TWH crankshafts are available in both standard stroke and extended stroke specifications, offering flexibility for stock replacement or power upgrades. We also provide full-coverage and bakelite-based (phenolic resin) variants, delivering enhanced durability and precise fitment for a wide range of scooter engines.
Dio 50 Long Stroke Crankshaft
High-Strength Design for Maximum Performance
The AF series Full-Coverage Long-Stroke Crankshafts are made for the Honda Dio 50 motor scooter, crafted using high-strength forging and precision machining to enhance durability and power output. The extended stroke design effectively increases the compression ratio and combustion efficiency, delivering stronger torque and improved acceleration.
DIO-ZX Long Stroke Crankshaft 41.4mm(+2.0mm)
Reinforced Design for Enhanced Power Output
The ZX Full-Coverage Long-Stroke Crankshaft is crafted from high-strength forged steel, offering outstanding durability and torsional resistance to ensure stable and long-lasting engine performance. The 41.4mm (+2.0mm) long-stroke design effectively increases the compression ratio and combustion efficiency, delivering greater torque and acceleration—perfect for high-performance modifications.
🔹 High-Strength Forged Crankshaft – Provides exceptional rigidity and durability
🔹 41.4mm (+2.0mm) Long-Stroke Design – Increases displacement for improved acceleration and torque output
🔹 Precision Dynamic Balancing – Reduces vibrations for stable high-RPM operation
🔹 Compatible with ZX Models – Suitable for various modifications
Product Specifications
✔ Stroke Size: 41.4mm (+2.0mm)
✔ Material: High-strength forged steel
✔ Compatible Models: ZX AF34/35
✔ Design Features: Enhanced power output and optimized combustion efficiency
✔ Package Includes: Crankshaft, connecting rod
Whether you're aiming for high-RPM stability or improved acceleration, the ZX Full-Coverage Long-Stroke Crankshaft is the perfect choice for high-performance upgrades!
KR 150 Full Matel Crankshaft (15pin)
Full coverage. Precision stroke. Reliable foundation.
This Full Metal Crankshaft for Kawasaki KR150 is available in two stroke lengths: 54.4 mm (standard) and 55.4 mm (+1.0 mm), both with a 15 mm piston pin. The full-coverage counterweight design ensures balance and durability under high load, making it suitable for both OEM replacement and mild displacement upgrades. Each crankshaft is precision-machined for consistent fitment, ensuring smooth rotation and long service life.
Highlights
Two Stroke Options — 54.4 mm (STD) for OEM spec; 55.4 mm (+1.0 mm) for added stroke and torque potential.
15 mm Piston Pin — Strength-focused size for performance reliability.
Full Coverage Design — Reinforced counterweights for stability at higher RPM.
Precision Machined — Tight tolerances for smooth rotation and consistent sealing.
OEM-Compatible — Direct fit for KR150 engine cases without modification.
Product Specifications
✔ Stroke: 54.4 mm (STD) / 55.4 mm (+1.0 mm)
✔ Piston Pin: Ø15 mm
✔ Type: Full Metal Crankshaft (full-coverage design)
✔ Fitment: Kawasaki KR150
✔ Package Includes: Full Metal Crankshaft ×1
Installation Notes
Confirm stroke specification (STD / +1.0 mm) before purchase.
For +1.0 mm stroke, check squish clearance, compression ratio, and jetting.
Always use new bearings and oil seals during installation.
Recheck crankshaft end play and torque after initial run-in.
Power You Can Trust.
JOG 50 Long Stroke Bakelite Crankshaft 41.4mm(+2.2mm)
Faster primary compression. Longer-stroke torque. OEM-fit assembly.
This Bakelite Crankshaft for Yamaha JOG 50 pairs Bakelite (phenolic) inserts with a 41.4 mm (+2.2) long stroke. The inserts reduce crankcase dead volume to sharpen primary compression, while the added stroke increases displacement potential for stronger low-to-mid pull—once cylinder height, timing, and fueling are set correctly. Precision journals and OEM-matched tapers keep assembly straight and predictable.
Highlights
🔹 +2.2 mm Long Stroke — 41.4 mm stroke broadens torque potential after proper top-end setup.
🔹 Primary-Compression Boost — Bakelite stuffers trim case volume for quicker pressure rise off the line.
🔹 Cleaner Case Flow — Web shaping guides mixture more directly toward the transfers.
🔹 Precision Interfaces — Tapers/threads/keyway match OEM bearings and ignition hardware.
🔹 Build-Ready — Designed for straightforward truing, seal fit, and clearance checks.
Product Specifications
✔ Type: Bakelite-stuffed long-stroke crankshaft
✔ Stroke: 41.4 mm (+2.2)
✔ Fitment: Yamaha JOG 50 (confirm year/engine code)
✔ Interfaces: OEM-match main-shaft tapers, threads & keyway
✔ Bearings/Seals: Compatible with OEM-spec main bearings & oil seals
✔ Material: Forged steel webs & connecting rod, Bakelite inserts
✔ Package Includes: Crankshaft assembly ×1
Installation Notes
Set cylinder height/base spacer, compression ratio, and squish clearance for the +2.2 stroke.
Re-evaluate port timing, ignition advance, and fueling/jetting for the longer stroke and higher case pressure.
Confirm small-end pin diameter and bearing spec match your piston/rod kit.
Check crankcase/web clearances, measure runout after bearing install, use new seals, and complete a careful break-in.
Power You Can Trust.
JOG 90 Long Stroke Bakelite Crankshaft 45mm(+3.0)
Faster primary compression. Longer-stroke torque. OEM-fit build.
This Bakelite Long-Stroke Crankshaft for Yamaha JOG 90 combines Bakelite (phenolic) case-stuffing inserts with a 45.0 mm (+3.0) stroke. The inserts trim crankcase dead volume to sharpen primary compression, while the added stroke raises displacement potential for stronger low-to-mid pull—once cylinder height, timing, and fueling are set correctly. Precision journals and OEM-matched tapers keep assembly straight and predictable.
Highlights
+3.0 mm Long Stroke — 45.0 mm stroke broadens torque potential after proper top-end setup.
Primary-Compression Boost — Bakelite stuffers reduce case volume for quicker pressure rise off the line.
Cleaner Case Flow — Web shaping helps direct mixture efficiently toward the transfers.
Precision Interfaces — Tapers/threads/keyway match OEM bearings and ignition hardware.
Build-Ready — Designed for straightforward truing, seal fit, and clearance checks.
Product Specifications
✔ Type: Bakelite-stuffed long-stroke crankshaft
✔ Stroke: 45.0 mm (+3.0)
✔ Fitment: Yamaha JOG 90 (confirm year/engine code)
✔ Interfaces: OEM-match main-shaft tapers, threads & keyway
✔ Bearings/Seals: Compatible with OEM-spec main bearings & oil seals
✔ Material: Forged steel webs & connecting rod, Bakelite inserts
✔ Package Includes: Crankshaft assembly ×1
Installation Notes
Set cylinder height/base spacer, compression ratio, and squish clearance for the +3.0 stroke.
Re-map port timing / ignition advance / fueling to suit the longer stroke and higher case pressure.
Confirm small-end pin diameter and bearing spec match your piston/rod kit.
Check crankcase/web clearances, measure runout after bearing install, use new seals, and complete careful break-in.
Power You Can Trust.
AEROX Full Matel Crankshaft 64.7mm(+6.0)
Longer stroke. Broader torque potential. Built for clean, repeatable fitment.
This Full-Coverage Long-Stroke Crankshaft is engineered for Yamaha AEROX builds targeting a 64.7 mm (+6.0) stroke. Full-coverage crank webs and precision-finished journals support sealing area and rigidity, while OEM-matched interfaces help the assembly drop in cleanly (with proper top-end setup). Pair with the correct cylinder/head stack and fueling to realize tractable low-to-mid pull.
Highlights
🔹 64.7 mm Long Stroke (+6.0) — Expands displacement potential for stronger low-to-mid response after proper setup.
🔹 Full-Coverage Webs — Broad cheek coverage supports crankcase sealing area and structural stiffness.
🔹 Precision Interfaces — Main journals and tapers finished for straight, true running and reliable alignment.
🔹 Build-Ready Geometry — OEM-fit mating surfaces ease assembly and shim/clearance checks.
🔹 Tuning Friendly — Designed to work with appropriate cylinder height, combustion chamber, cam/port timing, and fueling.
Product Specifications
✔ Type: Full-coverage long-stroke crankshaft
✔ Stroke: 64.7 mm (+6.0)
✔ Fitment: Yamaha AEROX (confirm engine variant/year)
✔ Focus: Displacement/torque increase potential, assembly precision
✔ Package Includes: Crankshaft ×1
Installation Notes
Verify cylinder height/stack (base gasket/spacer) and squish/compression to suit the +6.0 stroke.
Re-set cam timing / port timing and fueling/ECU or jetting as required for the longer stroke.
Confirm big-end/small-end dimensions and bearing specs match your piston/rod kit.
Check crankcase clearances and oiling; torque to spec and inspect runout before final assembly.
Power You Can Trust.