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RETROL R29 4.2CC Miniature V-Twin Engine Motor OHV for Mini Chopper Bike Motorcycle - RETROL 4-Stroke & Inline Engines
RETROL

RETROL R29 4.2CC Miniature V-Twin Engine Motor OHV for Mini Chopper Bike Motorcycle

★★★★★
5.00 / 5.0 (6 verified reviews)
$849.99 USD $899.99 Save $50.00

Engineering Summary

The RETROL R29 4.2CC Miniature V-Twin Engine Motor OHV for Mini Chopper Bike Motorcycle is a 1/5 4.2CC 4-Stroke & Inline Engine precision-engineered by RETROL. Features construction machined from brass + stainless steel and operating on 95# Gasoline. Available for $849.99 USD with free worldwide tracked shipping, 30-day returns, and replacement parts support at Stirlingkit.

✓ Free Worldwide Shipping: Tracked air delivery in 5–14 business days.
✓ Missing Parts Guarantee: Free replacement parts dispatched within 7 days.
✓ 30-Day Risk-Free Returns: Full refund on unbuilt kits in original box.

Technical Specifications

25 Verified Parameters
Material Brass + Stainless Steel
Item No R29
Color Silver
Scale 1/5
Form Ready to Run
Type Double-Cylinder Four-Stroke Gasoline Engine
Displacement 4.2CC
Cylinder Diameter 13mm
Stroke 16mm
Cooling Mode Air Cooling
Starting Mode Manual/Electronic Drill Starting
Ignition Method Electronic Igniter
Spark Plug Type 1/4-32 Thread ME8 Spark Plug
Lubrication Method Mix/Splash Lubrication (Gasoline/Engine Oil =25/1)
Fuel Type 95# Gasoline
Engine Oil Type 2T Engine Oil
Starting Power 4.5V AA Batteries*3 (Not Included)
Engine Dimensions 120*80*110mm
Wooden Base Dimensions 150*120*30mm
Product Dimensions 15 x 12 x 14cm
Product Weight 1650g
Package Dimensions 20 x 20 x 20cm
Package Weight 1850g
Packing Carton Box
Ages 14+https://www.tiktok.com/@rustyvanranch/video/7459894830953532715?is_from_webapp=1&sender_device=pc

Features, Architecture & Package Contents

@rustyvanranch

miniature knucklehead by Stirling Kit

♬ original sound - Rusty

 

 

R29 4.2CC  Miniature V-Twin Engine Motor OHV  for Mini Chopper Bike Motorcycle

in stock. the order will be sent out within 1 working day.
Features:


.Based on the V-twin double-cylinder Knucklehead motorcycle engine in the 1970s, the miniature gasoline mini knuckle head engine model embodies the spirit of different ages in a wonderful way.
.Designed with classic body lines and cold-cooling structure, the retro machine restores a host of authentic engine details, including a new carburetor and lift throttle.
.Each part of the engine was carefully designed, processed as well as made of brass and stainless steel, working in conjunction with a wooden base for easy display&control and stable operation.
.Built with start and ignition equipment, the engine is ready to run and friendly to novice model enthusiasts. When running, you will satisfy and marvel at its operation.
.As a coveted collection, the engine model is worth showing and playing, suitable for personal use and a high-end gift to friends and families at major festivals.
.Notes: 1. If the engine is failure to start normally under the normal ignition and cylinder compression, it is likely that the carburetor needle will need to be adjusted.
2. After tightening the main oil needle on the carburetor, loosen 1/4 turn and start the flywheel to make the mixture ratio of gasoline and air reach the normal working mixture ratio after several times.
3. Turn off the power switch when the machine stops.

Specifications:

.Material: Brass + Stainless Steel
.Item No: R29
.Color: Silver
.Scale: 1/5
.Form: Ready to Run
.Type: Double-Cylinder Four-Stroke Gasoline Engine
.Displacement: 4.2CC
.Cylinder Diameter: 13mm
.Stroke: 16mm
.Cooling Mode: Air Cooling
.Starting Mode: Manual/Electronic Drill Starting
.Ignition Method: Electronic Igniter
.Spark Plug Type: 1/4-32 Thread ME8 Spark Plug
.Lubrication Method: Mix/Splash Lubrication (Gasoline/Engine Oil =25/1)
.Fuel Type: 95# Gasoline
.Engine Oil Type: 2T Engine Oil
.Starting Power: 4.5V AA Batteries*3 (Not Included)
.Engine Dimensions: 120*80*110mm
.Wooden Base Dimensions: 150*120*30mm
.Product Dimensions: 15 x 12 x 14cm
.Product Weight: 1650g
.Package Dimensions: 20 x 20 x 20cm
.Package Weight: 1850g
.Packing: Carton Box
.Ages: 14+https://www.tiktok.com/@rustyvanranch/video/7459894830953532715?is_from_webapp=1&sender_device=pc

Verified Builder Reviews (6)

Authentic feedback from hobbyists, machinists, and scale model engineers

5.00 / 5.0
★★★★★ (6 total)
Larry Bush Verified Buyer
★★★★★

Well built engine !

This little engine is great in detail and manufacturing quailty !

William Swink Verified Buyer
★★★★★

knuckle head

it was purchased as a gift to my best friend.

Randy Vickery Verified Buyer
★★★★★

Great little engine

The engine started with very little adjustments needed to the carburetor. Fun to play with. It worked better using the pull rope to start it than the adapter with a cordless drill. Detail on motor is incredible.

Gil Garceau Verified Buyer
★★★★★

Knucklehead V-Twin R29 by Retrol (Micorocosm)

It is a very nice recreation of the iconic Knucklehead V-Twin Harley Davidson engine. I have started it about 40 times so far and have found it quite reliable and easy to start by hand with a simple twist of the flywheel between my thumb and forefinger. You can purchase here and get the discount from this link or use the discount code REDRYDER for any and all of the products on Stirlingkit. Link to Knucklehead R29: https://bit.ly/3y0fURE Link to V-Twin Vtwin engines: https://bit.ly/3SphCUU Have a great year! Gil RedRyder reddrryder

Frank Schiavo Verified Buyer
★★★★★

awesome knuckle head mini

I am a Harley builder and love this motor.

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