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Top 10 Alien products – best-selling models in 2026!
Ranking updated: 1 January 2026'
Discover Alien’s best-selling products. Top 10 hits loved by motorcyclists – see which models are number one in 2025!
Top 7 products
- Cast iron cylinder complete Alien WSK 125
- Cast iron cylinder complete Alien Junak M10
- Alien R4 76.00 mm complete piston Junak M07 M10
- Alien R4 53.00 mm complete piston WSK 125
- Alien R4 62.50 mm complete piston SHL M11 175 Osa
- Complete piston Alien Nominal 61.00 mm WSK 175
- Alien R5 39.25 mm complete piston Romet 2B 3B
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1. Cast iron cylinder complete Alien WSK 125
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Piston:
the piston was made of high-grade aluminum alloy with silicon content of 22%
subjected to a two-stage heat treatment process
has a low coefficient of expansion under the influence of temperature
reduced mass ensures slim engine operation without increased vibration
the anode coating results in a lower coefficient of friction which has a positive effect on piston expansion
microporosity of the coating improves oil film retention on the shell surface improving lubrication
higher surface hardness makes seizure more difficult
the piston can be used both for connecting rods with needle bearing in the head as well as with original bearing on a bronze bushing
shell geometry based on barrel profile, ovalised
High quality surface finish and low bottom roughness minimize carbon build-up
rings are made of the same type of cast iron as the factory piston rings, so the original resilience is retained
equipped with additional lubrication holes in the pin hubs
C-type piston pin protection, such as on modern motorcycles -
Cylinder:
the cylinder was made of high quality cast iron in a geometry that ensures visual consistency with the original
9-rib version used for almost the entire production period of WSK M06 models
sleeve finished with honing
channel windows have been chamfered at the factory
the intake channel has a tongue to support the piston ring in the lowest piston position (the lack of this element in cheaper substitutes, results in destruction of the piston groove)
covered with heat-resistant black paint resistant to gasoline and petroleum derivatives
thanks to precise workmanship exemplary fit was obtained -
The kit includes: / Kit contents:
Alien cast iron cylinder
anodized Alien 52.00 mm piston
piston pin
piston protector
Alien piston ring set
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2. Cast iron cylinder complete Alien Junak M10
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Piston:
was made of high-grade aluminum alloy with a silicon content of 20%, which guarantees low expansion of the material
casting subjected to a two-stage heat treatment process, finally anodized
mantle geometry based on barrel profile, ovalized
high quality final machining and smooth piston bottom, which eliminates carbon sticking
the nominal weight of the ALIEN piston is in the range 275-278g guaranteeing optimum balance and eliminating vibration
additional material bumps in the valve pockets to avoid collision of the piston with the valves
raised piston bottom relative to the original to increase compression ratio
microporosity of the coating improves oil film retention on the mantle surface improving lubrication
higher hardness of the piston surface, hinders its seizure
type C piston pin protection known from modern motorcycles (made of high quality spring steel)
the piston pin is internally graded and press-fit -
Cylinder:
the cylinder was made of high quality cast iron in a geometry that ensures visual conformity with the original
sleeve finished with honing
covered with heat-resistant black paint resistant to gasoline and petroleum derivatives
thanks to precise workmanship exemplary fit was obtained -
The kit includes: / Kit contents:
cast iron cylinder Alien 75.00
anodized Alien piston
graded piston pin
type C piston protector kpl
set of Alien piston rings
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3. Alien R4 76.00 mm complete piston Junak M07 M10
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General description
the piston was made of high-grade aluminum alloy with a silicon content of 20%
low coefficient of thermal expansion of the material
casting subjected to a two-stage heat treatment process, final anodized
mantle geometry based on barrel profile, ovalized
high quality finishing and smooth piston bottom, which eliminates carbon build-up
exemplary fit with appropriate clearance
the nominal weight of the ALIEN piston is within the range 275-278g guaranteeing optimum balance and eliminating vibration
additional material bumps in the valve pockets to avoid collision of the piston with the valves
raised piston bottom relative to the original to increase compression ratio
microporosity of the coating improves oil film retention on the mantle surface improving lubrication
higher hardness of the piston surface, hinders its seizure
type C piston pin protection known from modern motorcycles (made of high quality spring steel)
the piston pin is internally graded and press-fit -
The set includes
Alien anodized piston
piston pin, stepped
type C piston protector (2pcs)
set of piston rings (3pcs)
instruction manual
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4. Alien R4 53.00 mm complete piston WSK 125
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General description
designed for Polish motorcycles such as WSK 125 with 13mm pin
the piston was made of high grade aluminum alloy with silicon content of 22%
subjected to a two-stage heat treatment process
has a low coefficient of expansion under the influence of temperature
reduced weight ensures slim engine operation without increased vibration
the anode coating results in a lower coefficient of friction which has a positive effect on piston expansion
microporosity of the coating improves oil film retention on the shell surface improving lubrication
higher surface hardness makes seizure more difficult
the piston can be used both for connecting rods with needle bearing in the head as well as with original bearing on a bronze bushing
shell geometry based on barrel profile, ovalised
High quality surface finish and low bottom roughness minimize carbon build-up
rings are made of the same type of cast iron as the factory piston rings, so the original resilience is retained
equipped with additional lubrication holes in the pin hubs
C-type piston pin protection, such as on modern motorcycles -
The set includes
ALIEN piston with anodic coating
Alien piston ring x 2 pcs.
C-type piston protector x 2 pcs.
13mm piston pin
instruction manual with values for fits and practical information on assembly
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5. Alien R4 62.50 mm complete piston SHL M11 175 Osa
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General description
designed for Polish motorcycles such as SHL M11 175 with S32 engine (three-speed) or Osa M52
the piston was made of high grade aluminum alloy with 20% silicon content
has a low coefficient of thermal expansion
thanks to the anode coating, a lower coefficient of friction was obtained, which has a positive effect on piston expansion
microporosity of the coating improves the behavior of the oil film on the surface of the shell improving its lubrication
higher surface hardness makes seizure more difficult
jacket geometry based on barrel profile, ovalized
high quality surface finish and low bottom roughness minimizes carbon build-up
rings are made of the same type of cast iron as the factory piston rings, so the original resilience is retained
includes high quality piston pin protector made by Italian company Beneri -
The set includes
ALIEN piston with anodic coating
piston ring x 2 pcs
Italian Beneri piston protector x 2 pcs
15mm piston pin
instruction manual with values for fits and practical information on installation
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6. Complete piston Alien Nominal 61.00 mm WSK 175
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General description
designed for Polish motorcycles such as WSK 175, SHL Gazelle and SHL 175 M11W (Wiatra W2A four-speed engine)
the piston was made of high grade aluminum alloy with 20% silicon content
has a low coefficient of thermal expansion
thanks to the anode coating, a lower coefficient of friction was obtained, which has a positive effect on the expansion of the piston
microporosity of the coating improves the behavior of the oil film on the surface of the shell improving its lubrication
higher surface hardness makes seizure more difficult
jacket geometry based on barrel profile, ovalized
high quality surface finish and low bottom roughness minimizes carbon build-up
rings are made of the same type of cast iron as the factory piston rings, so the original resilience is retained
equipped with additional lubrication holes in the pin hubs
G-type piston pin protection, such as on modern motorcycles -
The set includes
ALIEN piston with anodic coating
Alien piston ring x 2 pcs.
G-type piston protector x 2 pcs.
18m piston pin
instruction manual with values for fits and practical information on installation
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7. Alien R5 39.25 mm complete piston Romet 2B 3B
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General description
designed for Polish mopeds such as Komar, Romet, Ogar 205, Motorynka, Kadet
the piston was made of high grade aluminum alloy with silicon content of 20%
has a low coefficient of thermal expansion
thanks to the anode coating, a lower coefficient of friction was obtained, which has a positive effect on the expansion of the piston
microporosity of the coating improves the behavior of the oil film on the surface of the shell improving its lubrication
higher surface hardness makes seizure more difficult
the piston can be used both for connecting rods with needle bearing in the head as well as with original bearing on a bronze bushing
shell geometry based on barrel profile, ovalised
High quality surface finish and low bottom roughness minimize carbon build-up
the rings have been made of the same type of cast iron as the factory piston rings, so the original resilience is retained
the height of the ring groove has been reduced from the factory height of 2.50mm to 2.00mm for compatibility with commercially available rings for the Simson S51
rectangular side lock changed to internal lock
material selection in the pin hub is an important design element that reduces the volume of material in the area that expands most strongly during operation
the piston hubs have been lengthened to work better with the needle bearing to ensure minimum cage movement, and to guarantee adequate lubrication
equipped with additional lubrication holes in the piston pin hubs
C-type piston pin protection, such as in modern motorcycles -
The set includes
ALIEN piston with anodic coating
2.0mm high piston ring x 2 pcs.
C-type piston protector x 2 pcs.
12mm piston pin
instruction manual with values for fits and practical information on installation
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