RETROL R31 4.2cc V-Twin Shovelhead Miniature Gasoline Engine Model Gift
Hero Section: The Icon of the 60s, Reborn in Brass
The 1960s gave birth to one of the most distinctive engine silhouettes in motorcycle history: the "Shovelhead." The RETROL R31 is a kinetic love letter to that era. With its signature rocker box covers resembling the back of a coal shovel, this 4.2cc V-Twin engine captures the raw, mechanical soul of the American highway. Crafted from gleaming brass and stainless steel, it isn't just a model; it is a running, breathing piece of industrial art that brings the garage to your desktop.
Why Choose the RETROL R31 Shovelhead?
- Aesthetic Mastery (The Brass Edition): Unlike standard aluminum models, the R31 utilizes high-quality brass for the main engine block and cylinders. This gives it a stunning, golden "steampunk" aesthetic and a substantial weight (1.2kg) that feels premium and heirloom-worthy.
- The "Shovelhead" Legacy: The unique shape of the rocker boxes is instantly recognizable to any gearhead. This model faithfully reproduces that classic profile, combined with the complex V-Twin firing rhythm that defines the golden age of choppers.
- Complex Engineering: This is one of the most sophisticated engines in the RETROL lineup. It features upgraded intake and exhaust valves for better breathing, resulting in a noticeable power increase and a deeper, more aggressive exhaust note.
- Ready-to-Run (RTR): We believe the joy is in the running. The engine arrives pre-assembled on a handcrafted wooden base, with the ignition system and spark plugs installed. Just add batteries and fuel, and you are ready to start.
Technical Highlights: Engineering Deep Dive
- 4.2cc Displacement: This "Big Block" miniature offers significantly more torque than smaller 1.6cc engines. The larger displacement allows for a more stable, rhythmic idle that mimics the "potato-potato" sound of a full-sized V-Twin.
- Advanced Carburetion: The R31 features a newly designed carburetor with a toggle throttle lever. This allows for precise control over the air-fuel mixture, making the engine easier to start and more responsive to throttle inputs.
- Effective Air Cooling: The deep-finned brass cylinders utilize a "cold cooling" structure designed to maximize surface area. This ensures the engine dissipates heat effectively, allowing for longer run times without overheating.
- CDI Electronic Ignition: While the look is vintage, the spark is modern. The CDI system ensures a hot, consistent spark for reliable ignition, even at lower RPMs.
Specifications
- Brand: RETROL
- Model: R31 (Shovelhead Style)
- Scale: 1/5
- Displacement: 4.2cc
- Cylinder Diameter: 13mm
- Stroke: 16mm
- Material: Brass / Stainless Steel / Wood
- Cooling: Air-Cooled
- Ignition: CDI Electronic Igniter (Requires 3 x AA Batteries)
- Spark Plug: 3/16-40 Inch Thread
- Fuel: 95# Gasoline
- Lubrication: Mixed Fuel (Gasoline/Oil = 25/1)
- Starting Method: Electric Drill or Manual Start
- Dimensions: 150 x 120 x 140mm
- Weight: 1200g
Usage Scenario: The Mechanic’s Meditation
It’s a quiet evening in your study. You place the R31 on your desk, the brass gleaming under the lamp. You mix a fresh batch of fuel (25:1). You flip the switch and use the drill starter to wake the beast. The engine coughs, then catches, settling into that heavy, syncopated V-Twin rhythm. You adjust the toggle throttle, watching the rocker arms work. It’s a moment of pure focus, a tangible connection to mechanical history that clears the mind and sparks conversation.
Important Tips from the Workshop
- The Golden Ratio (25:1): This engine uses splash lubrication. You must mix 2T engine oil with your 95# gasoline at a ratio of 25:1. Running straight gasoline will damage the cylinder walls.
- Tuning the Needle: If the engine has compression and spark but won't start, the carburetor needle likely needs adjustment. Gently tighten the main oil needle, then loosen it about 1/4 of a turn. This is the standard "sweet spot" for starting.
- Shutdown Safety: Always turn off the power switch immediately when the engine stops running to prevent the ignition coil from overheating and draining your batteries.
Customer Support
We are dedicated to keeping the spirit of mechanics alive. If you need assistance with tuning, spare parts, or maintenance, please contact our support team at service@helloworld7.com.
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