Video by Lee Gavin via YouTube
Source
How to adjust the speed of the Rooder r804t8-Eec.
1. Left brake
2. Power on
3. Gear 3
4. Full speed
5. Power on/off the front light 3 times within 5 seconds
6. The digital flashes on the screen
7. Right turn light, higher speed, left turn light, lower speed.
8. Turn off the turn light, and then power on/off the front light to save new speed.
9. Power off, done.
10. Warranty WhatsApp: +8613632905138