Group 19: Gate 4

Product Reassembly

This is the final review of the product before the submission of the project. By now, we have finished the reassembly of our product and restored it to the condition as it was received. Like our previous gates, we focused on the transmission of the engine as the primary component of our reassembly. This involved the process of putting together the clutch, the gear-shift drum, the starting motor and various gears that make up the transmission. Once the transmission was secured, we had to wait for Group 31 to finish their part of the reassembly which included various internal components of the engine such as spark plugs, the crankshaft, the alternator and generator as well as the carburetor. After this step, we continued with the remainder of the reassembly process by putting the covers on the clutch, the carburetor and the alternator. We also reattached the camshafts, the cylinder head covers, the starting motor and the air cleaner.

A major challenge that halted our progress towards completing the reassembly process on time was the academic scheduling of our group members and Group 31’s members. Also, the office hours were not able to compensate for our busy schedules which made it very difficult to reassemble the engine on time. To resolve this problem, we communicated with Professor Devendorf and explained our situation. By giving us an extension on the reassembly process, we were able to complete the product reassembly in one sitting and prepare our notes for Gate 4.

Our product reassembly process is listed in the following table, Table 1: Product Reassembly, accompanied by the tools used for each step. We have created a new difficulty scale for the reassembly process as our previous one was tough to understand.

The difficulty scale ranges from 1 to 5. “One” represents a component that was effortless to reassemble and “Five” represents a component that was more challenging to reassemble due to the number of parts and location of the component.

Table 1: Product Reassembly

STEP	PROCESS	TOOLS	DIFFICULTY
1	Attach cam chain to the cam chain tensioner	12mm socket wrench	5
2	Attach alternator cover	8mm socket wrench	2
3	Put starting motor back on engine block	7mm socket wrench	3
4	Attach clutch cover	10mm socket wrench	2
5	Attach crankcase cover	8mm socket wrench	2
6	Attach cylinder head cover	8mm socket wrench	2
7	Attach air cleaner housing	Philips head screwdriver	1
8	Attach carburetor caps	Philips head screwdriver	1
9	Attach air cleaner cover	Philips head screwdriver	1
10	Attach water pump	Torx screwdriver	3
11	Put together back casing of engine	4.5mm Allen key	3

For an easier visual of each reassembly process, Table 2: Step-Picture-Part is available on the following page to further explain and help visualize the processes of Table 1: Product Reassembly.

Table 2: Step-Picture-Part

STEP	PICTURE	PART
1		Cam Chain and cam chain tensioner
2		Alternator cap
3		Starter motor
4		Clutch Cover
5		Crankcase cover
6		Cylinder head cover
7		Air cleaner housing
8		Carburetor cap
9		Air cleaner cover
10		Water pump
11		Back casing

Reassembly vs. Dissection

We did not completely reassemble the engine by ourselves. The engine was assigned to us with Group 31. We faced many scheduling conflicts during dissection as well as during reassembly. We were not able to work with Group 31 on dissection or reassembly at all during the course of the project, therefore, communication was always carried out by e-mail. This made it much more difficult to meet the deadlines on time, as stated in the introductory paragraph of this document.

The reassembly was different than the dissection in regards to the difficulty of the processes. Reassembling the engine and the transmission was much easier than taking it apart because we took great dissection notes to help us with the reassembly. We also referenced many of the dissection pictures we took to help recognize various parts and their locations when putting them back together. The most laborious part of the reassembly process was putting the correct part on first. The engine is not meant to be put together by untrained hands and therefore many parts are extremely difficult to fit in their proper positions without first putting together the correct part that should already be in that location. This elongated our reassembly process but by referencing our dissection notes and pictures, we were able to meet our extended deadline.

Functionality

Our product was a 1994 Honda 599CC engine. We decided to focus on understanding and breaking down the transmission. After the dissection, we were able to see that the transmission on our engine functioned very well. We have embedded a video of the transmission on our wiki page as well as an explanation of how the gearshift drum forks shift the gears as the rider steps on the shift lever. We were able to understand exactly what kind of gear would be reached depending on how the rider steps on the shift lever. This shifting mechanism is explained in the video.

Even though the transmission was fully functional on its own, the engine was far from it. A lot of the electrical equipment such as the alternator, the battery and the starter motor could not be tested. The exhaust, fuel and air systems were also not functioning. The functionality of our engine is very limited unless it is attached to the proper bike and all of the electrical components are connected in their proper places.

To see how our transmission works, click this link: http://www.youtube.com/watch?v=QTXUX-DPgsY

Recommendations

1) Removing the top gear allows an adjustment to the gearing so that the motorcycle will achieve a faster acceleration. This will also decrease the weight of the transmission, since fewer components will be used. It will make manufacturing cheaper; however this will result in a slight decrease in fuel economy. Since there are fewer moving parts the chance of mechanical failure seems less likely of a hazard.

2) Using a better lubricant will allow the moving parts to be more frictionless. This may increase the cost, but it will decrease the frictional force between the parts, making them move smoother and removing lost forces from the engine. Less friction means less heat and general wear and tear, meaning that the life of the transmission lengthens.

3) Replacing the steel parts with newer, lighter alloys of titanium will greatly lighten the transmission. This means that less force from the engine will be wasted moving the transmission and that extra energy will be put to power the wheels. The new alloy will be stronger and decrease the chance of mechanical failure. However, the alloys will increase the overall cost of the engine and its various components. It will also take much longer to manufacture the parts composed of the new alloys.

4) A universal screw head would make the dissection and the reassembly process much easier. This would eliminate the need for the 5 torx screws that are currently on the engine. Manufacturing a universal screw head would be cheaper in the long run because it would eliminate the need to manufacture various tools used for the dissection and reassembly.