• The newest design of the Avenger 85 2025 gas-powered two-stroke bike engine kit features a 52mm big bore, a four-hole balancing crankshaft, and an 80km/h top speed.

    Cylinder design by Ken Hinson/ Kelly Cansler. Faster then Phantom 85 v3 v2 v1 aswell as lower displacement engines on the market BT, YD, LD and PK. 

    The standard bike can be transformed into a motorized bike with this 85cc gasoline engine kit. You can enjoy riding at a faster speed—up to 80 km/h—after upgrading your bike. It makes your outdoor journey more convenient because it runs nearly as quickly as a motorcycle or scooter. Most 26" or 28" bikes with a V-frame can be fitted with this engine package.


    Specification:

    Mode of Engine: Single cylinder, air-cooling, 2-stroke

    Bore & Stroke:52mm & 40mm

    Rated Power:2.05Kw/5000r/min (3 horsepower/5000r/min)

    Max Power:3.5Kw/6000r/min (5-6 horsepower/6000r/min)

    Ignition Mode:CDI

    Model of Chain: 415

    Chain Length: 110 links

    Compression Ratio:6:01

    Driving Ratio:12.5:01

    Fuel Type:No.90

    Capacity of Tank:2L

    Speed Limitation:80km/hour

    Lubrication Oil: oil of 2-stroke petrol engine (Or oil for 10W/40.10W/30)

    Type of Sparking Plug:Z4C 14MM

    Volume of oil Consumption:2.5L/100km

    Type of Clutch:Friction Plate / Dry

    Cooling Mode:Natural air cooling

    Fit for most type 24" 26" and 28" bikes, such as mountain bikes, road bikes,cruisers, choppers.


    Extra notes: This engine features a four-hole balanced crankshaft, a larger cylinder head, a 12*16*12mm needle bearing, a high-performance CDI and magneto coil, and an a upgraded design of silencer.

    Fuel/Oil Ratio recommend by manufacturer: 

    New Engine (500km or approx 3-5 tanks):

    20:1 or 50ml of oil per litre.

    After Break In: 25:1

    25:1 or 40ml of oil per litre.

    IMPORTANT (Please read):

    1.      In order to create a suitable steal on the intake and stop any air leaks, please do not remove the plastic insert or o-ring that comes with your carburator.

     

    2.      To prevent exhaust from snapping at welds, use the exhaust strapping kit that some kits come with if necessary. Alternatively, you can purchase a JB Weld Metal Strapping Kit. 

     

    3.      To prolong the life of these components, it is advised to clean and regrease the clutch arm, bucking bar, and bevel gear every few weeks.

     

     

    4.      Fuel/Oil Ratio recommend by manufacturer: New Engine (500km or approx 3-5 tanks): 20:1 or 50ml of oil per litre. After Break In: 25:1 or 40ml of oil per litre.

    Using a different oil ratio than what is advised may speed up engine wear and cause engine seize. Don't assume the ratios instead, use a two-stroke mixing container to measure the oil. Our engine kits come with a 30-day warranty from the date of delivery. If you use a different oil mix ratio, this warranty will be void.

  • Terms and Conditions of Delivery

     

    Thank you for shopping with us. Please read the following Terms and Conditions of Delivery carefully before placing your order. By purchasing from our website, you agree to the following delivery terms.

     

    1. Shipping Methods

     

    We ship orders using the following methods:

     

    • Australia Post

       

    • CouriersPlease

       

    The shipping method used will depend on the size, weight, and destination of your order.

     

    2. Untracked Shipping for Small Items

     

    For small items, we may use untracked envelope delivery via standard post. These items will be delivered to your mailbox without tracking. By selecting or accepting this shipping method, you acknowledge and accept the associated risks, including possible delays.

     

    3. Processing and Dispatch Times

     

    • Orders are typically processed within 1–3 business days.

       

    • Dispatch times may vary during peak periods, sales, or due to unforeseen circumstances.

       

    4. Delivery Timeframes

     

    Estimated delivery times:

     

    • Standard Delivery: 2–8 business days (depending on location)

       

    • Express Delivery (if available): 1–3 business days

       

    These timeframes are estimates only and not guaranteed. Delays caused by the carrier or external factors (e.g., weather, public holidays, etc.) are beyond our control.

     

    5. Tracking Your Order

     

    • If your order includes tracking, you will receive a tracking number via email once dispatched.

       

    • Orders sent via untracked envelope post will not include tracking or delivery updates.

       

    6. Delivery Address

     

    Please ensure all delivery details are correct at the time of purchase. We are not responsible for parcels delayed, lost, or returned due to incorrect or incomplete address information provided by the customer.

     

    7. Missed Deliveries and Redelivery

     

    If delivery is attempted and unsuccessful, a card may be left with instructions for redelivery or collection. If an item is returned to us due to non-collection, additional charges may apply for redelivery.

     

    8. Lost or Delayed Parcels

     

    • Please contact us if your parcel has not arrived within the expected timeframe.

       

    10. International Shipping

     

    Please get in touch with us directly if you require international shipping we may arrange this for an additional fee.

     

    11. Changes to These Terms

     

     

    We reserve the right to update or change these delivery terms at any time. Any changes will be posted on this page and apply to all orders placed after the date of update.

  • Returns Policy

     

    Thank you for shopping at Monster Electronics.

     

    We aim to provide high-quality products and excellent customer service. Please read the following returns policy carefully before making a purchase.

     

    No Change-of-Mind Returns

     

    At monster-electronics.com, we do not accept returns or offer refunds for change-of-mind purchases. Please choose carefully before completing your order, and feel free to contact us with any product questions before buying.

     

    Australian Consumer Law

     

    Our products come with guarantees that cannot be excluded under the Australian Consumer Law (ACL). You are entitled to a replacement or refund for a major failure and compensation for any other reasonably foreseeable loss or damage. You are also entitled to have the goods repaired or replaced if they fail to be of acceptable quality and the failure does not amount to a major failure.

     

    If your item is faulty, damaged, or not as described, please contact us within 7 days of receiving your order at:

     

    Email: monsterelectronicshelp@gmail.com

     

    Please include your order number, a description of the issue, and photos if applicable.

     

    Warranty and Faulty Items

     

    If a product is found to be defective or not working as intended:

     

    • We will assess the issue.

       

    • If the item is confirmed to have a major fault, we may offer a refund, replacement, or repair, in accordance with ACL.

       

    • Return postage for faulty items may be covered by us depending on the circumstances.

       

    Contact Us

     

    For all warranty or product concerns, please email us at:
    monsterelectronicshelp@gmail.com

     

     

    We are committed to resolving any legitimate issues in line with your rights under Australian law.

  • About Us

     

    Welcome to Monster Electronics — Australia’s go-to destination for bike engine kits and smart tech accessories.

     

    We specialise in high-quality motorised bike kits, parts, and accessories that help you take your ride to the next level. Whether you're building your first motorised bicycle or upgrading an existing setup, we’ve got the tools, components, and expertise to get you moving.

     

    Alongside our core range of bike engine kits, we also stock a selection of clever gadgets and electronic accessories that make life easier and more fun.

     

    Why shop with Monster Electronics?

     

    • Top-quality bike engine kits, trusted by Aussie riders

       

    • Fast, local shipping via Australia Post and CouriersPlease

       

    • Responsive Australian customer support

       

    We’re proudly Australian-owned and committed to delivering excellent value, reliable products, and a smooth online shopping experience from start to finish.

     

     

    Thanks for supporting a local business — and happy riding from the team at Monster Electronics!