Group 5 - Motorized Scooter (Goped)/Gate 4

Gate 4

Figure 1. Reassembled Product

Project Management: Critical Project Review

Cause for Corrective Action

There are currently no unresolved challenges in the group that need to be resolved. All difficulties in the earlier gates have been addressed and solved. Additionally, there have been no new challenges that have occurred since the last cause for corrective action report.

Although low scores were received for each gate, each group member felt that he had given a significant effort and had not provided unsatisfactory work. The grades given as a result were not met happily but were accepted as there was not much beyond that point that could be done.

Product Archaeology: Product Explanation

Product Reassembly

Ease of Reassembly

Throughout the reassembly process, there were no snags and very few difficult steps that the group encountered. The most difficult step was reassembling the front brake assembly in which we forgot how certain parts fit together so it needed to be looked up on the internet to find the proper order. A meaningful scale can be achieved based on a number of factors. The main factor would have to be how we as a group felt a certain step was difficult or not. Then one can look at if the step was done under ideal circumstances, what else would have needed to be done or what could have been avoided.

The Goped, after all parts are manufactured, the final product is hand assembled using all conventional tools. The only sub-component that was machine manufactured was the engine, which is then mounted by hand onto the frame. Our group used the same or similar tools for dis-assembly and reassembly. The engine was still able to be put back together by hand although that is not how it was initially assembled. In terms of our groups assembly process, the steps to dismantle the Goped were simply reversed to reassemble.

Complexity Scale

The complexity scale is based largely on the one used in Gate 2. Each rating is given based on level of 1 to 5 based on required skill and knowledge.

• 1: Extremely Simple: Requires little to no technical expertise and is performed with ease; intuitive
• 2: Relatively Simple: Slightly more effort required but still little to no technical knowledge required
• 3: Moderate Difficulty: Some technical expertise required, may take some effort to perform
• 4: Difficult: Requires technical know how, component may need some coercion to assemble
• 5: Very Difficult: More technical than other components, may require alternative methods to go about process (brainstorming to perform process with an unconventional method).

Overall, the reassembly of the Goped was simple and seamless, with only a single quickly resolvable issue posing any delay. This can mostly be attributed to the fact that the group became more familiar with the individual components of the product during dis-assembly and could more easily be put back together. The total time spent reassembling the product was roughly two hours, a longer time than anticipated because breaks needed to be taken in order to document each step.

Steps for Reassembly

Table 1. Product Reassembly
Step	Process	Difficulty	Figure
1	Insert crankshaft/piston assembly into case.	2	Step 1
2	Bolt halves of crankcase together using a 10mm Allen key.	2	Step 2
3	Slide piston into the case, being careful not to grind the piston against the walls too hard.	3	Step 3
4	Bolt the engine head to crankcase using a 10mm Allen key.	2	Step 4
5	Push cord into spark plug hole in order to jam the piston cycling.	1	Step 5
6	Inset woodruff key into slot on crankshaft. Make sure the indented side faces out.	1	Step 6
7	Slide flywheel over crankshaft and Thread flange nut onto crankshaft in front of flywheel using a 12mm socket.	2	Step 7
8	Bolt engine onto frame mounts with a 10mm socket.	2	Step 8
9	Bolt magneto onto engine with a 3mm socket.	2	Step 9
10	Bolt muffler over exhaust port using an Allen key.	2	Step 10
11	Bolt plastic shroud onto engine using a Phillips head screwdriver.	1	Step 11
12	Slide spark plug wire into mount on shroud. Then screw the outer shroud/pull start onto shroud/over flywheel with a Phillips head screwdriver.	2	Step 12
13	Bolt the intake manifold onto the engine head using a Phillips head screwdriver. The gasket needs to be secured under the engine shroud.	2	Step 13
14	Screw the throttle cable onto the carburetor mount by hand. Then mount the intake housing and carburetor onto the intake manifold. The bolt goes through the housing and the carburetor with a Phillips head screwdriver.	3	Step 14
15	Insert the two metal grates into the intake housing.	1	Step 15
16	Insert the foam filters into the intake housing.	1	Step 16
17	Snap intake housing cover into place.	1	Step 17
18	Slide spindle over crankshaft. Bolt the spindle bolt onto the spindle with an Allen key.	3	Step 18
19	Thread the fuel hoses through frame and connect lines to receivers.	4	Step 19
20	Bolt gas tank and rubber bushings onto mounts with a 10mm socket.	2	Step 20
21	Mount the deck and bushings onto the frame using a 5/32” Allen key and an 11mm socket.	2	Step 21
22	Stretch kickstand so that it fits in its mounts and stretch the return spring so that it hooks into its mounting hole. May require bending the spring with a pair of needle-nosed pliers.	4	Step 22
23	Mount the brake and throttle levers onto the handle bars with Phillips head screwdriver.	1	Step 23
24	Remove the string from the spark plug hole and thread in spark plug. Place cap over spark plug.	1	Step 24
25	Press wheel bearings and spacer into the front wheel.	1	Step 25
26	Press wheel bearings and spacer into the rear wheel.	1	Step 26
27	Slide the brake components over the bolt on the bottom of the T-bar in the following order: torsion wire, right fork, left fork. Then screw the cap nut onto the end of the bolt, and connect the brake cable.	4	Step 27
28	Bolt the front wheel onto the fork with a 14mm socket.	1	Step 28
29	Slide the rear wheel over the rear axle. Secure it by tightening down the quick-release system. It helps to put force down on the board to ensure contact with the spindle.	2	Step 29

Design Revisions

Centripetal Clutch

One social impact that the centripetal clutch presents is an increase in safety. Currently, when the rider is trying to stop, the brakes attempt to stop the front wheels, which requires overcoming the forward energy that the engine outputs at idle, along with stopping the momentum. Implement a clutch system would disconnect the engine’s cycling from the axle at idle. Therefore, when the brakes are applied, they only need to overcome the forward momentum of the rider and the Goped, and not the work that the engine puts out. What this means in terms of safety is that the Goped can be stopped much more quickly, and that the life span of the braking system can be extended.

Figure 2. Centrifugal Clutch Animation

Another social impact that the implementation of a centripetal clutch presents is that it makes the Goped a more recreation-friendly product. A popular pastime of urbanite and suburbanite children is to ride their bikes to points of interest, where they hang out while sitting on their bikes. The Goped is an extremely feasible alternative the bicycle for this activity, but it lacks the convenience of being able to easily stopped and started again, like a bike does, because stopping the Goped stalls the engine, which thereby requires it to be pull-started. By installing a centripetal clutch, the engine will be able to idle without causing forward movement. This also increases the favorability of using the Goped as a transportation device as it allows the user to conveniently stop at intersections. Before the clutch, if someone had to stop at an intersection, they would need to pull-start the engine again, which can become rather annoying very quickly.

Figure 3. Centripetal Clutch Diagram

Electric Starter

If a centripetal clutch system was implemented in the design revision of the Goped, the user would lose the ability to bump start the product. This would then require the user to operate the pull start whenever the Goped was shut off. Constantly using the pull start would become annoying and time consuming. To make operating the product easier for the consumer, another design revision would be adding an electric start to the engine. This would enable the user to start the Goped with the push of a button, making operations easier.

This effects the societal factor of the engineering design constraints .This design revision would make the Goped easier to use by reducing the effort needed to start the engine each time the engine is stopped and started. Electric starters on small engines are nothing new. Many products including snow blowers and pockets bikes have this feature included. The battery for the starter could be mounted under the deck, and it could be charged through normal operation of the Goped along with an external plug for charging with an outlet. The addition of the electric start would create a need for a design revision of the current engine. It would also add additional weight to the Goped. An electric starter would also raise the price of the Goped as well.

Figure 4. Electric Starter

Handle Bars

One design revision that should be considered is the addition of adjustable handlebars. Adjustable handlebars would provide increased comfort and accessibility for riders of all heights, which falls under the societal factor design revision. The current design does not allow the user to change the height of the handle bar and can potentially be uncomfortable for taller users. The way this could be achieved is through a telescoping system. This would most likely be implemented using a system similar to what is on current kick scooters. The system consists of a ring around the bar and a tension screw that would when tightened would lock in place or when loosened allow the inner bar to move. These changes would potentially expand the market the Goped could reach, as the Goped would be more comfortable for taller riders. The downsides to adding adjustable handle bars is it would require testing, to determine what the ideal height setting would be. Additionally market research would need to be done to see if this added feature would be profitable. Both the testing and research, along with the added material needed to make the adjustable handlebars, would cost money and ultimately be passed along to the consumer to drive up the cost which can potentially hurt sales of the Goped.