A simple way to assemble a bicycle motor with your own hands, without using a welding inverter, just a grinder and a drill. In addition to a bicycle and a 2-stroke engine (43cc - 52cc) from a Chinese petrol cutter, we also need:
Reducer aliexpress.ru/item/3281084339...
Driven sprocket from the f-50, f-80 bike motor and fasteners (link to star 44t) aliexpress.ru/item/3282814186...
The leading star 420 from the moped Alpha, Orion ... + washer of the trimmer reducer as an adapter (you can also use the native star from the 17t - 20t reducer as an adapter) because I did not find suitable leading stars (maybe I was looking badly, I don’t deny!)
Chain 420
These measurements, presented in the 0:45 video, are suitable for a bicycle with 28 "wheels. At the moment 1:22, I selected the markings for attaching the brackets manually, since the angle of the oblique part of the bicycle frame is different for everyone.
RECOMMENDED RATIO OF DRIVEN AND DRIVEN WHEELS FOR DIFFERENT BIKE WHEELS (unless, of course, you want to break the clutch within the next kilometers of driving. By the way, the clutch pads must be steel, not duralumin!):
↓ Wheel diameter - sprocket - driven sprocket ↓
20 "- 15 - 44
24 "- 13 - 44
28 "- 13 - from 48 and more (in my case 56)
At the moment 1:42 a hole for a 30mm reducer (you can of course drill it in the nearest lathe) I made all the other holes with an 8mm drill
Step drill link:
4-32mm - aliexpress.ru/item/3304485624...
10-45 mm - aliexpress.ru/item/3288216558...
At the moment 2:13 a profile pipe 40 * 40 2mm, the length was matched to the width of the gearbox
At the moment 2:45 a corner is needed as a stiffener
At 4:10, when installing the complete bracket with the gearbox, make sure that the clutch bell does not rest against the pad bolts. Although this is rare, it still happens, this is a factory marriage of gearboxes, it is solved by placing m6 washers between the retctor and the motor.
At the moment 5:36, I tried to get under way on a steep climb (in the frame, of course, it is not clear that this is an ascent, so I have to take my word for it)