FLX F2 Upgrade Manual

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  1. FLX Custom Aluminum Frame with Smooth Welds
  2. Kickstand
  3. Bafang 350W Motor with chainring and new cranks (Attached)
  4. Color Display with thumb throttle
  5. Thumb Cruise Throttle that works from 6 mph (10km/h)
  6. Bike Maintenance Stand
  7. Tools to complete the process, including:
  • 7.1.Brake Bleed Kit
  • 7.2.Cable Ties
  • 7.3.Fork Spacers
  • 7.4.Rear wheel adapter kit
  • 7.5.Seat sleeve to use your seat post in the larger diameter seat tube
  • 7.6.Wrench and hex keys of various sizes



  1. Rubber mallet
  2. Phillips screwdriver
  3. Rubbing Alcohol
  4. Clean Rag



We’ve designed this upgrade kit to maximize the number of components you can use from your first generation FLX. This way we can keep the waste to a minimum and keep the cost as low as possible for the FLX Family. All you have to do is remove the components of your original FLX bike and install them on the new frame with the new motor.

Here are all the components that can be transferred over from your first generation FLX:

  1. Battery Brakes
  2. Front Fork
  3. Derailleur/Cassette
  4. Wheels Chain
  5. Stem Handlebars
  6. Grips
  7. Seat post
  8. Chain Pedals



If you’re mechanically capable and follow the step by step instructions, the upgrade process should take approximately 3 to 4 hours. When you’re finished you’ll have turned your first generation FLX into a second generation FLX with more power and upgrades.

Warning: The information contained in this manual is provided for your convenience and is to be used at your own risk. FLX assumes no responsibility for damage to your bike, property or any injuries related with this process. Do not work on your bike if you are not capable. If you are unsure in any way, take it to a qualified professional.





( ! ) Start the disassembly on the ground.

1. Disconnect the cables underneath the neoprene sleeve in front of the handlebars.

2. Remove the battery.

3. Remove the battery housing by unscrewing 5 screws with a Philips screwdriver (1 extra screw is located behind the top housing) (pic 1.1.).Please make sure to put aside the screws in the same order as different types are used (pic 1.2.), Disconnect the power cables.


pic 1.1., 1.2.   

4. Remove the pedals by unscrewing them with a 15mm wrench. The left pedal has a reverse thread so needs to be unscrewed by turning clockwise. The right pedal is a regular thread so needs to be turned counter-clockwise.

5. Open the quick release on the seat tube, and slide the seat post out.

( ! ) Put the bike on the bike stand for easier handling. In order to balance it properly, attach it as shown in the picture. (pic 2)


pic 2


6. Remove both wheels.

7. Remove the thumb control pad with the 3mm hex key. (3.1.)

8. Remove the Display. Unscrew the 2 bolts with the 3mm hex key. (3.2.)


pic 3.1., 3.2.


9. Remove the rear brake caliper. Use the 5mm hex key to unscrew the 2 bolts. (4.1.)

10. Remove the brake pads. Unscrew the indicated bolt with the 3mm hex key (4.2.) and remove the brake pads. (4.3.)

11. Take the yellow brake block from the bleed kit and insert it into the brake pad housing. (4.4.)

( ! ) Warning: Oil will start dripping from the brake tubes once disconnected. Have something underneath to catch the oil.

12. Unscrew the brake line using the 8mm wrench. (4.5.)


pic 4.1., 4.2., 4.3., 4.4., 4.5.


13. Unscrew the anchor bolt with the 5mm hex key and release the shifter cable. (5.1.)

14. Pull the brake line and the shifter cable out of the frame.

15. To remove the chain, find the master link (longer chain link with a wider opening. (5.2.) Use the master link tool to disconnect the link.

16. Remove the derailleur hanger (leave the derailleur attached). Unscrew the bolt with the 5mm hex key. (5.3.)

17. Remove the handlebars. Unscrew the top cap bolt (5mm hex key) on the headset and loosen the 2 screws on the stem (4mm hex key). (5.4.)


pic 5.1., 5.2., 5.3., 5.4., 5.5.

18. Take a rubber mallet and gently tap the fork tube from above to remove the front fork. Please note the configuration of the lower cup and base plate of the headset (6) so you can install them correctly on the new frame. Hold the fork with your other hand so it doesn’t fall to the ground.


pic 6


( ! ) Apply grease to the steerer tube of the fork if needed.

1. Carefully insert the fork into the F2 head tube.

2. Replace the headset parts (1) base plate, (2) lower cup and (3) spacers (6) on the head tube (7). If your F2 kit includes an extra spacer, install it here.

3. Put the stem and the handlebars over the steerer tube of the fork and screw the bolt into the top cap with the 5mm hex key. Tighten the 2 bolts on the side of the stem with the 4mm hex key. (7)


pic 7


( ! ) Ensure that all cables are routed around the head tube properly.

4. Install the derailleur hanger (with the derailleur attached) with the 5mm hex key. ( 5.3.)

5. Insert the shifter cable through the hole at the front of the top tube (8.1). Insert the other end of the cable through the plastic screw (8.2). Re-connect the cable to the anchor bolt with the 5mm hex key. (8.3)


pic 8.1, 8.2, 8.3


6. Install the color LCD with the provided bolts and tighten the screws on the side with a 2.5 mm hex key.

7. Install the new thumb remote on the handlebars with the 3mm hex key.

8. Insert the seat sleeve into the seat tube. (9.1.)

9.Put the new seat post in the seat tube and tighten the clamp.


( ! ) Make sure the seat post is inserted at least to the minimum insertion depth which is marked by vertical lines on the seat post (9.2.).


pic 9.1, 9.2


Minimum seat post insertion depth is 5” (12.7cm). Use the seat post quick release to tighten the seat post. Failure to insert the seat post to the proper depth may overstress the seat tube, which could cause the frame to break and lead to a serious accident.


10. Connect the motor cut off cables (small cables coming off each brake lever) to the correct adapter (bike/f2-upgrade).

11. Route the rear brake line through the front hole in the top tube and out of the rear hole towards the rear brake.

12. Screw the brake line back into the caliper with the 8mm wrench (Bleed kit). (10)


pic 10





 ( ! ) Brake bleeding is challenging and should only be performed by experienced bike mechanics.


  • All tools required for this process are provided in the bleed kit, including the mineral oil.
  • Make sure to prepare a rag because the oil will drip from the brakes.


  1. Follow the instructions in the brake bleed kit.


  1. When finished, clean the brake lever, caliper and the rotor from both sides with alcohol.


  1. Put the brake pads back into the caliper and screw them in with the 3mm hex key.


  1. Place the caliper back on the bike. Loosely screw the bolts in with the 5mm hex key.


  1. Allow the caliper to be loose so it can move freely for any adjustments.


  1. Reinstall the back wheel.


  1. Hold the brake lever down so the pistons can adjust to the rotor. Now tighten the calipers all the way with 5mm hex key and let go of the lever.


  1. Spin the wheel to see if the rotor is scrubbing on the pads. If it is, loosen the bolts and repeat step 7.





  1. Put the chain back on and connect it with the master link. Use the master link tool to lock it in place.


  1. Install the front wheel.


  1. Screw in the battery housing (Make sure the correct screw type is used for the dedicated holes)


  1. Screw the pedals on the cranks with the 15mm wrench. (The Left pedal is a reverse thread. To tighten, turn anti clockwise).





1. Position the front wheel between your knees, looking back towards the rear of the bike.

2. Unscrew the top-cap with the 5mm hex key.

3. Loosen the two bolts on the stem with the 4mm hex key until the handlebars can move with a small amount of force.

4. Close one eye and align the stem with the bike frame.

5. Tighten the 3 bolts and check the alignment. If needed, adjust handlebars again.



1. Before adjusting the derailleur, ensure that the anchor bolt holding the cable is tight using the 5mm hex key. (11.1.)

2. Make sure the chain is in the highest gear.

3. Screw the Low limiter screw (11.2.) with a screwdriver to the point where the chain is in line with the smallest cog on the cassette.

4. Start to spin the pedals and shift the gears. If you shift and the chain doesn’t skip to the next gear as expected, start unscrewing the plastic screw (11.2.) on the derailleur and pedaling at the same time while changing gears, until the shift is completed smoothly.

5. Go all the way up through the gears into the lowest (First gear) and set the High limiter screw (11.2.) so the chain is in line with the biggest gear.

pic 11.1, 11.2.


6. Pedal and shift the gears slowly.

7. If the chain doesn’t shift on the lower gears, screw in the distance screw (11.2.) located in the rear end of the derailleur just behind dropout until you achieve a smoother shift.

8. If that doesn’t help, screw in the plastic screw little by little until chain skips to lower gear.