A group of students, including Monish Sareen, Steven Perera, Jignesh Shah and Obaid Yasin, from Mechanical Engineering (B. Tech. 2014-2018) restored a bike of yore. This project was centered on restoration and shape optimization of a two-stroke, 3-geared carbureted Rajdoot 175 bike. Restoration, here, means to restore it to its original working condition whereas for appearance, shape optimization has been performed which is centered on comfort and aerodynamics.
This project provides an understanding of the basics and deeper analysis on shape optimization parameters, disassembling and assembling of a Rajdoot 175 which can be extended to any other two stroke motorcycle. Students applied various theories and mechanisms learnt in four years of Mechanical and Automation Engineering.
Procedure followed while dismantling the motorcycle
- The bike was placed on a heighted platform for easy access to the bolts underneath.
- The seat was removed foe gaining access to the bolt which secures the fuel tank to the chassis.
- The sari guard was removed.
- Foot pegs were removed
- Fuel supply to the engine was cut off and the fuel tank removed.
- Crankcase was drained of all fluids by unscrewing the drain bolt.
- The wiring harness was completely taken apart except for the cable coming out from the magneto.
- The air box was removed.
- The carburetor was removed and kept in a container for further inspection.
- The spark plug was removed.
- The exhaust pipe was removed.
- The chain was removed from the rear sprocket and placed near the crankcase.
- All the bolts on the engine were loosened so as to facilitate easy disassembly of individual engine component.
- Engine mounting bolts were removed.
- Engine was removed and placed aside for further inspection.
- A makeshift stand made from steel bars was placed under the frame to facilitate the removal wheels.
- Axle nuts were loosened using sockets of various sizes.
- Rear and front wheels were removed.
- The rear wheel was completely rusted and hence was scrapped.
- The front wheel was taken apart to check the condition of the drum brakes.
- The bolts on the triple clamp were loosened.
- The front suspension was separated from the chassis.
- The springs on the rear were removed for removing the swing arm.
- The swing arm axle was removed after removing the nut and the axle key.
- The swing arm was removed.
Steps involved to work on the chassis:
- Cutting Operation
- Galvanization
- Abrasive Blasting
- Painting
Steps taken to assemble the motorcycle:
- Insert the seat post into the seat tube. Use 4mm Allen key to tight the seat clamp.
- Clamp the bike onto a bicycle repair stand.
- Use 4 mm Allen key to remove the stem cap and place the handlebar into the place.
- Use 4 mm Allen key to tight the bolts. (Note: 4 bolts need to be evenly tight.)
- Adjust the handlebar to your favourite angle.
- Remove all protectors off the bike.
- Place the rear brake cable housing into the cable holder on the frame.
- Pull the rear brake cable. (Note: Please make sure the rear brake cable end in the right position in the lever. Test it by applying brake lever.)
- Place the front brake cable housing into the brake caliper holder and pull the brake cable.
- Apply some grease on the front wheel skewer.
- Place the front wheel into fork.
- Please make sure the wheel is the centre of the fork than close the quick release lever to secure the wheel.
- Insert the front brake cable holder on the calliper as the picture.
- Holder the brake calliper and pull the cable, then use 5mm Allen key to secure the cable once it reaches perfect position.
- Tight the bolt to secure the brake cable.
- Close the brake tension adjustment lever.
- Adjust the brake pads height and make sure the pads could be applied on the wheel’s braking surface. Then leave reasonable extra and cut the brake cable using a cable cutter. (Note: Please do not cut too short, you might need to re-assemble the brake cable in the future.)
- Squeeze the cable end on the brake cable.
- Insert the rear brake cable into the holder (same as front).
- Adjust the brake pads height using 4mm Allen key and make sure the pads could be applied on the wheel’s braking surface.
- Squeeze the cable end on the brake cable.
- Leave a bit extra for future use.
- Pedals have different thread. Check the mark on the axle “L” means left pedal, “R” means right pedal. (Note: Drive side is right, non-drive side is left. Apply some grease on the pedal axle.)
- Turn the right pedal axle clockwise by hand.
- Lock the axle using a 15mm pedal wrench. (Note: Please do not scratch the painting of the crank arm. Reasonably tight, if too loose, the axle would move then potentially would damage the thread of the crank arm.)
- Left pedal installing by turning the axle counter clockwise by hand.
- Lock the axle using a 15mm pedal wrench.
- 5mm Allen key to tight the top lock first. (Note: Do not over tight; it may damage the bearing inside.)
- Adjust the handlebar angle paralleling to the front wheel and tighten the side bolts to lock the stem on the fork steerer.
- Pump the tyre using compatible air pump.
- Adjust the seat height and position.