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RFN Thunder140 Pro 140cc Pit Bike
RFN Pit Bikes

RFN Thunder140 Pro 140cc Pit Bike

£1,099.00

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  • Description

    RFN Thunder 140 Pro 140cc Pit Bike – Quick Overview

    Best for: experienced riders wanting serious off-road performance.

    Engine: genuine YX 140cc 4-stroke single-cylinder engine.

    Power: 11.15bhp with 10.2Nm torque.

    Wheels: 17 inch front / 14 inch rear big wheel setup.

    Why riders choose it: full manual control, big wheel stability, hydraulic brakes and high ground clearance.

    Our view: the top RFN Thunder petrol pit bike for riders who want the biggest, most capable bike in the range.

    The RFN Thunder 140 Pro is the biggest petrol pit bike in the RFN Thunder range. Built with a genuine YX 140cc engine, full manual gearbox, 17/14 big wheel setup and upgraded hydraulic brakes, it is made for riders who want more size, more power and more serious off-road capability.

    This is not a beginner pit bike. The Thunder 140 Pro is designed for experienced riders who already understand clutch control and want a bike that can handle tracks, trails and motocross-style riding.

    With an 84cm seat height, 32.5cm ground clearance and 80kg dry weight, it feels much closer to a compact motocross bike than a small junior pit bike.

    My Take as a British MX Rider

    The RFN Thunder 140 Pro is the one I’d look at if the rider wants the most serious bike in the Thunder petrol range.

    The 17/14 wheel setup, 84cm seat height and YX 140cc engine give it a much bigger, more capable feel than smaller pit bikes.

    If the rider is confident with a manual clutch and wants the biggest RFN Thunder petrol bike, this is the one to go for.

    Why Upgrade to the RFN Thunder 140 Pro?

    Feature Smaller Pit Bikes RFN Thunder 140 Pro
    Engine Lower-capacity beginner or progression engines Genuine YX 140cc 4-stroke engine
    Gearbox Often automatic, semi-auto or smaller manual setups Full manual 4-speed gearbox
    Wheel Setup Smaller 10/10, 12/10 or 14/12 setups 17 inch front / 14 inch rear big wheel setup
    Ground Clearance Lower junior-style clearance 32.5cm ground clearance
    Best For Beginners or developing riders Experienced riders wanting the biggest RFN Thunder option

    The RFN Thunder 140 Pro is the better choice if the rider has outgrown smaller pit bikes and wants a bigger, more powerful manual bike with serious off-road capability.

    Why Choose the RFN Thunder 140 Pro?

    Genuine YX 140cc Engine

    The proven YX 140cc engine gives strong, usable power and a serious step up from smaller bikes.

    Full Manual Gearbox

    A 4-speed manual gearbox gives experienced riders full control over power delivery.

    17/14 Big Wheel Setup

    Bigger wheels improve rollover, stability and confidence across rougher ground.

    Hydraulic Brakes

    Dual piston front and single piston rear hydraulic brakes deliver strong stopping control.

    Adjustable Rear Shock

    The rebound-adjustable hydraulic rear shock allows setup changes for terrain and rider style.

    Top Thunder Model

    The biggest and most capable bike in the RFN Thunder petrol pit bike range.

    Where Does the RFN Thunder 140 Pro Fit in the Range?

    Smaller RFN Thunder Bikes
    Better for riders still developing confidence or needing less size and power.
    RFN Thunder 140 Pro
    Top Thunder model with 140cc power and 17/14 big wheels.
    Manual Pit Bikes
    Browse full manual clutch pit bikes.

    Is the RFN Thunder 140 Pro Right for Your Rider?

    Choose the Thunder 140 Pro If...

    • The rider is experienced with manual pit bikes
    • You want the biggest RFN Thunder petrol model
    • You want a genuine YX 140cc engine
    • The rider needs 17/14 big wheel stability
    • You want a pit bike that bridges the gap towards motocross

    Consider a Smaller Pit Bike If...

    • The rider is still learning clutch control
    • This is their first petrol pit bike
    • You want a lower or lighter bike
    • The rider does not need 140cc power yet
    • The 84cm seat height or 80kg dry weight is too much

    Rider Sizing Guide

    Important: the RFN Thunder 140 Pro should be chosen by rider height, strength and experience — not age alone.

    With an 84cm seat height, 80kg dry weight and 75kg maximum rider weight, the Thunder 140 Pro is best suited to experienced riders who are physically ready for a large manual pit bike.

    Best For Experienced riders wanting serious off-road performance
    Experience Level Experienced manual rider only
    Seat Height 84cm
    Dry Weight 80kg
    Wheel Size 17 inch front / 14 inch rear
    Max Rider Weight 75kg

    If you are unsure whether this is the right step, compare options using our Best Pit Bike for Beginners UK guide.

    Big Wheel 140cc Pit Bikes: Why They Matter

    A big wheel 140cc pit bike gives riders more stability, stronger performance and a more motocross-style riding feel compared with smaller pit bikes.

    The RFN Thunder 140 Pro combines proven YX engine performance with a larger 17/14 chassis setup, making it ideal for riders wanting a more serious off-road machine.

    Engine, Gearbox & Riding Feel

    The genuine YX 140cc engine gives the Thunder 140 Pro strong acceleration, usable torque and a more aggressive riding feel than lower-capacity pit bikes.

    The full manual 4-speed gearbox gives experienced riders proper clutch control and full command of the bike’s power delivery.

    Combined with the 17/14 wheel setup, 32.5cm ground clearance, USD forks and hydraulic braking package, the Thunder 140 Pro feels substantial, capable and built for hard off-road use.

    What’s in the Box?

    • RFN Thunder 140 Pro 140cc pit bike
    • Final assembly components

    The bike is supplied boxed or partly assembled. Final assembly, mechanical checks and safety inspection are required before use.

    Assembly should be completed by a mechanically capable adult. Always check bolts, brakes, chain tension, controls, oil and fuel before riding.

    Specifications

    Below you'll find the key technical specifications for the RFN Thunder 140 Pro, including engine details, suspension, braking, wheel size and rider sizing.

    Engine YX 140cc 4-Stroke Single Cylinder — Air Cooled
    Max Power 11.15bhp at 8,000rpm
    Max Torque 10.2Nm at 7,500rpm
    Compression Ratio 9.8:1
    Bore x Stroke 56 x 57mm
    Fuel System Carburettor
    Ignition Key Ignition
    Start Kick Start
    Transmission Manual 4-Speed (N-1-2-3-4)
    Final Drive Chain
    Top Speed 75km/h
    Fuel Capacity 3.2 Litres
    Front Suspension USD Forks — Non-Adjustable
    Rear Suspension Rebound Adjustable Hydraulic Shock
    Front Brake Hydraulic Dual Piston — 220mm Ventilated Wavy Disc
    Rear Brake Hydraulic Single Piston — 190mm Ventilated Wavy Disc
    Front Wheel 17 inch Steel Rim / Alloy Hub
    Rear Wheel 14 inch Steel Rim / Alloy Hub
    Front Tyre 70/100-17
    Rear Tyre 90/100-14
    Wheelbase 122cm
    Seat Height 84cm
    Ground Clearance 32.5cm
    Dry Weight 80kg
    Max Rider Weight 75kg
    Warranty 30 Days Parts Only

    Warehouse Stock & Fast UK Delivery

    Online-Only Specialist Pit Bike Retailer

    Garland Powersports is an online-only specialist retailer focused on performance electric bikes, pit bikes and youth off-road machines.

    RFN pit bikes are held securely in warehousing and dispatched across the UK.

    Delivery options: at checkout, you can choose boxed delivery for the fastest and best-value option, or select a built and ready-to-ride service if you would prefer the bike assembled, safety checked and prepared before delivery.

    Boxed delivery is the best-value option and requires final assembly before riding. Built and ready-to-ride options are available for customers who want the bike prepared before it arrives.

    Fast UK delivery available across the full RFN pit bike range.

    Frequently Asked Questions

    Is the RFN Thunder 140 Pro suitable for beginners?

    No. The RFN Thunder 140 Pro is best suited to experienced riders. It has a full manual gearbox, 140cc engine, tall 84cm seat height and 80kg dry weight.

    Is the RFN Thunder 140 Pro manual?

    Yes. The Thunder 140 Pro uses a full manual 4-speed gearbox with clutch control.

    What engine does the RFN Thunder 140 Pro use?

    It uses a genuine YX 140cc 4-stroke single-cylinder air-cooled engine.

    How powerful is the RFN Thunder 140 Pro?

    It produces 11.15bhp at 8,000rpm and 10.2Nm of torque at 7,500rpm.

    What is the seat height?

    The RFN Thunder 140 Pro has an 84cm seat height.

    How heavy is the Thunder 140 Pro?

    The dry weight is approximately 80kg.

    What wheels does it have?

    It uses a 17 inch front and 14 inch rear big wheel setup.

    How fast is the RFN Thunder 140 Pro?

    The listed top speed is 75km/h, depending on rider weight, terrain and conditions.

    Can the RFN Thunder 140 Pro be used on the road?

    No. The RFN Thunder 140 Pro is not road legal. It is designed for private land and off-road use only.

    Does it need assembly?

    Yes. The bike is supplied boxed or partly assembled and requires final assembly, setup and safety checks before riding.

    Our Verdict

    Choose the RFN Thunder 140 Pro if the rider is experienced and wants the biggest, most capable petrol pit bike in the Thunder range.

    Choose a smaller pit bike if the rider is still learning clutch control or needs a lower, lighter bike.

    Choose an electric RFN option if you want instant electric power with less petrol maintenance.

    For experienced riders wanting a big wheel 140cc petrol pit bike that bridges the gap towards motocross, the Thunder 140 Pro is the top RFN Thunder choice.

    Ready to Choose the RFN Thunder 140 Pro?

    The RFN Thunder 140 Pro is the flagship petrol pit bike in the Thunder range, built for experienced riders who want 140cc manual power, big wheel stability and serious off-road performance.

    Order online today from Garland Powersports with fast UK delivery.

    Shop All Pit Bikes View RFN Pit Bikes

  • Delivery & Returns

    Delivery options and estimated timescales are shown at checkout based on your location and the delivery methods available to you. All orders are carefully packaged to ensure your bike arrives in perfect condition.

    RFN pit bikes are covered by a parts-only warranty. This means that in the event of a valid warranty claim, a replacement part will be supplied — labour, fitting costs and any associated expenses are not covered.

    The warranty covers manufacturing defects and component failure under normal use. It does not cover:

    • Fair wear and tear
    • Damage caused by incorrect assembly or setup
    • Damage resulting from misuse, abuse, racing, or modification
    • Consumable items including tyres, brake pads, chains, sprockets, filters and fluids
    • Damage caused by lack of maintenance or incorrect maintenance
    • Cosmetic damage including plastics, graphics and bodywork
    • Damage caused by an accident or impact

    Warranty claims must be accompanied by proof of purchase and, where required, photographic evidence of the fault. We reserve the right to request that parts are returned for inspection before a replacement is issued.

    Returns

    If you wish to return an item, please contact us before sending anything back — we are unable to accept returns without prior authorisation.

    Unused / Unwanted Items
    Unused items may be returned within 30 days of delivery in their original, unassembled condition and original packaging. Return postage costs are the responsibility of the buyer. A refund or exchange will be issued once the item has been received and inspected.

    Faulty or Damaged Items
    If your item arrives damaged or develops a fault, please contact us as soon as possible with your order details and photos of the issue. We will assess the claim and respond with the appropriate resolution — which under the parts-only warranty will typically be a replacement part dispatched to you.

    Please Note
    Once a pit bike has been assembled, fuelled, or ridden it cannot be returned as an unwanted item. If you are unsure whether a bike is right for you before purchasing, please get in touch and we'll help you make the right choice.

RFN Thunder140 Pro 140cc Pit Bike
£1,099.00