VARUN S20-1 Adult Electric Bike User Manual

Important Safety Warnings

Please mind potential fire risk and strictly follow the instruction manual for charging and storage. While using the product, please wear protective equipment and fully comply with the applicable law and regulations.

• Always wear a helmet when riding the electric bike.
• Keep both keys properly.
• Ensure your e-bike has a full battery before riding.
• Always respect pedestrians.
• Avoid riding in humid conditions; electric bike may slip and cause injury. Humid environments can also damage electronic devices.
• Always observe local laws and regulations for electric bicycles.
• Do not disassemble parts; contact us for standard parts if needed.
• Avoid prolonged exposure to sunlight or rain. Do not store in hot places or places with corrosive gas.
• E-bikes are a risky mode of transportation; follow road rules. Brake the rear wheel first, then the front wheel to avoid falling.
• Before riding, carefully check the state of the body. Improper operation or use is your responsibility.
• Each bike has a unique frame number (located in the head tube). Record and save it.
• If local laws do not allow speed regulating handles (rotary handle/accelerator), do not install or use them on VARUN products.
• Before your first ride, check that all parts/screws are tightened or locked (wheel clamps, saddle clamps, etc.).

Product Overview

The Varun S20-1 is a 20-inch foldable fat tire electric road bicycle designed for urban daily commutes. It features a powerful 48V 10.4Ah lithium battery, a peak 750W motor, and a smart LCD display for an enhanced riding experience. For more detailed diagrams and visual aids, please refer to the official user manual PDF available at: https://manuals.plus/m/06f1eab81e5542351d459dfd79760cfedbffea651b28041f15c1e905c8ad9558

Key Features:

• Ergonomic Design: Three-dimensional body structure designed according to ergonomics, mechanics of materials and aesthetics, contributing to the best riding effect.
• Lightweight & Stylish: Modern appearance with quality materials for safe and easy operation.
• Electric Safety System: For riding safety, the electric safety system will cut off power automatically when braking.
• EU Law Compliant: The bicycle is designed according to EU laws (rated speed: 25KM/H), safeguarding riding.
• Mechanical Bell: The bicycle is equipped with a mechanical bell. While riding the bicycle, the sound of bell and motor does not exceed the A-weighted emission sound pressure level requirement of 70dB(A) at workplace.

Packing List

Please inspect the contents of the package carefully. If anything is missing or damaged, contact VARUN customer service.

Assembly and Installation

For your safety, please wear protective gloves before installation. Improper assembly may cause risks of loss of control, bumping, or falling. Apply proper force when assembling the bicycle. Too tight or too loose tightening may cause damage or failure. Do not assemble or repair the bicycle without powering it off.

Note: The installation steps may vary slightly depending on the product model. The specific in-kind product shall prevail. Please refer to the corresponding installation steps for your purchased model.

Installation Video Guide

Step-by-Step Installation Instructions:

1. Unpacking and Film Removal: Carefully remove the protective film from the bike components.
2. Check Components: Verify all parts listed in the packing list are present. Remove both keys and keep them safe.
3. Bicycle Head Installation:
   • For S20-1/S20-2 models: Insert the upper part of the handle riser into the lower part, locking the retaining structure in the middle. Stand the riser vertically and lock the folders at the bottom. Ensure the handlebar structure is secure and not wobbly.
   • To ensure stability, set the head height within the scale. Do not exceed the limit line.
4. Saddle Installation:
   • Connect the seat and seatpost first, then insert the seatpost into the bar receiver. Adjust its position and height to suit your riding habits, then tighten the seat with the clamp.
   • Do not exceed the maximum saddle height and do not raise the saddle above the safety line.
5. Front Wheel Installation:
   • If your Ebike front wheel axle is hollow: Loosen the screws, place the front wheel on the fork, align the position, and tighten the screws. Pull out the center ring for easy installation. Align the holes and tighten the screws. Follow the same procedure for the other side, tightening until there is no more space.
   • If your Ebike front wheel axle is solid: Use a No.8 (M17 wrench) tool to loosen the fork retaining bar and remove it (this accessory prevents fork deformation during delivery). Place the front wheel into the forks, ensuring fork hangers are secured to the axle and the disc is centered in the brake. Tighten flange nuts on both sides using a No.7 (M15 wrench) tool.
6. Mudguards and Headlights Installation:
   • Place the fenders first, then the lights. Put the washer first, then the nut, and finally tighten it.
   • For taillight (S20-1/S20-2/M26-2 PLUS): Remove taillight, install on rack, tighten screws. Connect the plug of the taillight cable and bind it to the shelf with a tie wrap.
7. Bicycle Pedals Installation:
   • Ensure pedal threads are fully inserted into the crank arm. Tighten pedals with a No.7 (M15 wrench) tool.
   • Turn the pedal labeled "L" counterclockwise into the left crank and the pedal labeled "R" clockwise into the right crank.
   • Tighten with a wrench so that it does not come loose while riding.
8. Adjustments (Brake Levers, Gauges, Shifter, Throttle, Bell): Adjust the angle of these components on the handlebars, then tighten with a tool.
9. Battery Installation:
   • Open the battery compartment, place the battery at the correct angle, gently insert it into the holder, and press it down until it locks automatically.
   • Insert the key into the keyhole and rotate it to align with the "OFF" icon; the battery is now locked and cannot be removed.

Operating Instructions

Meter Introduction (S20-1/S20-2 Model)

The instrument panel features three buttons: the “Power Button," the "Plus Button (+),” and the “Minus Button (-).”

Setup Instructions:

• Boost Mode: When stationary, press and hold the "-" button to display the static boost indicator, entering boost mode. In boost mode, vehicle speed shall not exceed 6 km/h.
• Unit Settings: Press and hold the combination keys (“+” and "-" keys) on the standby interface to enter custom parameter settings. P1 is the metric/imperial unit selection option (00 for metric (km), 01 for imperial (mile)). Briefly press the power button to enter parameter change mode. Press the +/- keys to select parameters. Press the power button to save settings and return to the custom parameter selection screen.
• Restore Factory Settings: Press and hold the combination keys ("+" and "-" keys) on the standby screen to enter the personalized parameter settings interface. dF is the Factory Reset option (N for do not reset, Y for reset required). Briefly press the power button to enter parameter modification mode. Briefly press the +/- keys to select parameters. Press the power button to save settings and return to the personalized parameter selection interface.
• Mileage Clear Settings: Press and hold the combination keys ("+" and "-" keys) on the standby screen to enter the custom parameter settings interface. P7 is the mileage clear setting option. Press and hold for over 3 seconds to reset the mileage.

Battery Instructions

Before using this product, first turn on the power switch on the side of the battery. Press “-” to turn on the power switch. In key position 2, the battery is "locked" (battery locked to frame, key removed, bike can be ridden). In key position 1, the battery can be moved and removed. Press the “O” button on the side power button.

Charging Guidelines for Safe Handling:

• Use the original special charger only.
• Note the chargeable battery type and applicable voltage. Do not mix different battery types.
• Charging time shall not exceed 12 hours, and charging current shall not exceed 3A.
• Insert the charger probe into the charger port on the electric bike battery.
• Insert the tip of the wire into the battery charger.
• The red indicator will stay on until fully charged, then turn green.

Brake Adjustment and Use

Before aligning the mechanical disc brake, make sure the brake cable is properly inserted into the lock lever. If the disc rotor is bent or damaged, replace it first.

Adjusting Brake Sensitivity:

• If the brake is not flexible: Loosen the fixing bolt of the brake cable, shorten the braking distance, and then tighten the bolt.
• If the brake is too sensitive: Increase the distance of the brake cable.

Disc Brake Alignment:

• If the rotor is always rubbing against the brake pad or has excessive clearance: Loosen the two centering adjustment screws (do not remove them).
• Turn the wheel slowly and check the space between the rotor and the brake pad. Adjust the position to avoid friction.
• After adjustment, tighten the screws.

Safe Braking Practice:

• The brake is for speed control, not just stopping. Practice gentle, progressive braking without locking the wheels.
• Push the lock lever towards the handlebar to gradually increase braking force.
• If wheels get stuck, reduce braking force to allow them to spin without being stuck.

Product Maintenance Instructions

Proper maintenance is critical for the performance and safe operation of your bicycle. The recommended intervals and need for lubrication and maintenance may vary depending on conditions the bicycle is exposed to. Always inspect the bicycle and conduct necessary maintenance before each use.

Basic Maintenance:

• For painted frames: Dust and remove loose dirt with a dry cloth. Clean with a damp cloth soaked in mild detergent, then dry and polish.
• For plastic parts and rubber tires: Clean with soap and water.
• For chrome-plated bikes: Wipe with a rust preventative fluid.
• Store your bicycle under shelter. Avoid leaving it in rain or exposed to corrosive materials.
• After riding on beaches or coastal areas (salt exposure): Wash frequently, wipe or spray all unpainted parts with anti-rust treatment. Ensure wheel rims are dry to prevent braking performance issues.
• If hub and bottom bracket bearings were submerged: Take out and re-grease to prevent accelerated deterioration.
• If paint is scratched/chipped to metal: Use touch-up paint to prevent rust. Clear nail polish can also be used.

Lubrication Schedule:

Parts Maintenance (Tires, Wheels, Drivetrain, Brakes):

Tires:

• Frequency: Inspect and maintain at least each use.
• Check tire pressure: Inflate to the pressure indicated on the tire sidewall.
• Check bead seating: Ensure the bead is properly seated while inflating or refitting.
• Tire Inflation:
  1. Remove valve cap and add air.
  2. Ensure tire is evenly seated on the rim, both sides.
  3. Spin wheel and check for high/low areas.
  4. Complete inflation to recommended psi.
  5. If not evenly seated, release some air and repeat steps 3-6.
  6. Check for dirt in valve cap or stem.
  7. Securely replace valve cap.

Wheels:

• Frequency: Inspect and maintain at least each use.
• Rims: Inspect for dirt and grease. Use a clean rag or wash with soapy water, rinse, and air dry.
• Wheels: Check if securely fastened and axle nuts are tight. Adjust if necessary. Spin wheel and check rotation/alignment.
• Spokes: Check for broken or loose spokes. See bicycle mechanic for repair.
• Hub Bearings: Lift each wheel and check for side-to-side movement. See bicycle mechanic for repair. If you do not own cone wrenches, do not attempt hub bearing adjustments.

Drivetrain (Pedals, Chains, Crank Set):

• Pedals (Monthly): Check security and tighten into crank arm. Before each ride, check front and rear pedal reflectors are clean.
• Pedal Bearings (Every ride): Check proper adjustment. If looseness or roughness is detected, adjustment, lubrication, or replacement is required.
• Chains (Weekly): Check if clean, properly lubricated, rust-free, not stretched, broken, or stiff links. Lubricate if necessary. Replace if rusted, stretched, or broken.
• Crank Set (Monthly): Check if crank arms, chain rings, bottom bracket axle, and bearings are correctly adjusted and tight. See bicycle mechanic for repair.

Brakes:

• Frequency: Inspect and maintain before each use.
• Levers: Check if securely fastened to the handlebar. Position levers to fit rider's grip and screw tight.
• Pads: Check pad position, gap, and pressure. See Section 9: Adjusting the Brakes.
• Cables: Check outer casing for kinks, stretched coils, and damage. Check cables for kinks, rust, broken strands, or frayed ends. Check housing is seated properly. Replace cable if needed. It is recommended that cables and housing be replaced every riding season.

Troubleshooting and Error Codes

If an electrical problem occurs, an "Error" and error code will be displayed. Refer to the table below for detailed meanings and resolutions.

Error Codes:

Common Faults and Solutions:

Specifications (S20-1 Model)

Please confirm the product model and find corresponding parameters.

User Tips

• For optimal endurance mileage, use the pedal assist mode.
• Avoid frequent braking when safety is ensured.
• Do not overload the bike.
• Maintain correct tire pressure (generally 20PSI / 1.4BAR).
• Weight less than 120kg for a better comprehensive riding experience.
• Speed and range vary depending on road conditions, weather, and rider weight.
• To prevent battery issues, clean battery contacts regularly and ensure the battery is correctly placed and secured.
• If the display shows errors or goes out, check battery contacts and connections to the control unit.
• You can ride in moderate or light rain, but ensure the bike is completely dry before the next ride. Do not park in rain or wade through water.
• Charge the battery in a timely manner and avoid leaving it empty. If not used for a long time, charge every 2 months to prevent battery starvation.

Warranty and After-Sales Support

VARUN Electric Bike is committed to providing a safe, comfortable, and environmentally friendly way of traveling. We focus on functionality, design, quality, and customer experience.

Warranty Statement:

In addition to statutory warranty, VARUN grants a one-year warranty for electronic components such as the motor, control unit, display, and battery after customer registration. Wear parts (brakes, calipers, brake pads, lamps, etc.) are excluded. Defects caused by accident or improper handling are not covered.

Conditions that Void Warranty:

• Failure to follow instructions in the user manual.
• Single vehicle collision, accident, or damage due to careless parking.
• Illegal behavior.
• Not registered or unable to provide an order number.
• DIY repair of electronic products.
• Misuse on off-road terrain, dirt, snow, water, sand, gravel.
• Use as a rental unit.
• Damage from natural disasters (earthquake, lightning, fire, flood).
• Prolonged exposure to rain, hail, snow, or direct sunlight causing rust/paint discoloring.
• Overload exceeding recommended load.
• Damage from nails, needles, broken glass, debris, sharp stones, or other foreign objects.
• Jumping from ramps, stairs, or elevated ramps (stunts).
• Use for competition or racing.
• Modifications to engine, electrical system, suspension, or battery.
• Use of unapproved components.
• Damage caused by improper care and handling.
• Damage caused by over-discharge or under-discharge of the battery.
• Damage caused by collision.

Important: To protect your after-sales rights, please retain the bicycle carton and packaging materials after unboxing your bicycle! This is essential for future after-sales service. Discarding the carton will significantly hinder bicycle transportation.

After-Sales Services:

For any questions or warranty claims, please contact VARUN customer service. We aim to reply and solve problems within 24 hours.

• Email: support@varunebike.com
• When contacting, please provide your order number and bike serial number (located on the frame head tube).
• It is best to describe your problem in detail and send pictures or a video for quicker resolution.

Battery Handling Precautions:

• Recycle or discard the battery in an environment-friendly way.
• Do not throw the battery into fire; it may explode or leak.
• Do not discard the battery in ordinary household garbage.