Group 13 - Gate 4: Product Archaeology

Product Reassembly

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Reassembly Difficulty Scale

During the reassembly there were various steps that required different amounts of work, effort and tools. The difficulty of each step was broken down into three different levels based on a criteria created by Group 13. The different levels of difficulty are described below:

Team 13 Difficulty Table

	Team Members Required	Tools Required	Effort Required	Number of Fasteners Used	Number of Components	Number of Subsystems Involved
Possible Points	1-4	1+	1-3	1+	1+	1+
Scale Criteria	This part of the scale was graded based on the number of team members needed for the step. One point was given for each member that was needed during the process.	In this step one point was given for each tool that was used. There was no cap on the amount of points given during this step. (Note: A socket and its drive counted as to points, considering one drive was used with multiple sockets in some cases.)	The effort scale was based on three different categories of effort, the first being minimal which meant the persons performing the job put no effort in, parts could be connected and assembled with no strength or force needed. The second was moderate effort, meaning that effort was needed but the job only gave moderate resistance and required effort, but nothing strenuous for the team member. The final score for the effort, was maximum, which meant that the step required an extreme amount of force, and parts that were very resistant to fastening. Fasteners required larger amounts of torque and parts were heavy and difficult to align and reassemble. One to three points were awarded for this scale, one, two and three points given respectively for the different amount of effort.	In this step one point was awarded for each piece of hardware used in the reassembly, there was no cap to the amount of points a step could accumulate.	This section of the criteria, points were given for the amount of components that were involved in the reassembly. The points were given for the number of components that were involved in the mating of the two involved parts during the reassembly.	The last part of the criteria gave points to the number of subsystems that were involved in the step being evaluated by the criteria.

Table-A: The above rubric is for the evaluation of the difficulty of each step completed during the reassembly of the Honda Engine. The larger the amount of points that a step scores based on the criteria the more complex the step was. It contains the possible points that each step could score and the description of how and why the points were given to each step.

In the following documentation of the reassembly, the aforementioned difficulty criteria were applied to describe the complexity of each step.

Procedure:

The reassembly was performed in the lab, located in Furnas Hall, during the allotted office hours. It was performed by a combined effort of Team 13 and Team 23. The following is an account of the assembly completed by Team 13:

Reassembly Steps:

Step I

Transmission: The first step of the reassembly was to put the various transmission components back in the casing. The main shaft and counter shaft need to be reassembled with their respective components as well as the transmission gears. This part consisted of putting the oil pump sprocket and chain on the input side of the main shaft. Next the main shaft and then the counter shaft were mounted on the shifting forks within the casing. Tools: A 3/8 drive with 8, 10 and 12mm sockets. Snap ring spreader. Difficulty: 97

Transmission: This shows the transmission after the major components have been replaced.

Step II

Clutch Basket: The second step of the reassembly was to put the clutch back together in proper operating order. The clutch basket can be slid right onto the input shaft of the transmission, note the shaft may need to be lifted from its seat in the transmission to do this. Tools: None Difficulty: 8

Clutch Basket: The clutch basket mounted on the main shaft of the transmission.

Step III

Clutch: The following step reassembled all of the clutch components together. The clutch/friction plates were mounted on the inner guide of the clutch. With the plates in place the inner guide could be attached to assure they stay in place, followed by the outer guide. The components were then mounted on the housing. Next the pressure plate was mounted on the clutch basket. Finally the whole assembly was mounted on the input shaft in the transmission. Tools: A 3/8 drive with a 10mm socket. Difficulty: 16

Clucth: The clutch fully assembled with in the basket, and properly mounted on the input shaft.

Step IV

Crankshaft: The following step of the reassembly involved seating the crankshaft in the crankcase. The crankshaft was set in the lower half of the crankcase. Then aligned to its proper position with sin the case. Tools: None Difficulty: 4

Crankshaft: Crankshaft seated within the lower half of the crankcase.

Step V

Pistons: The following step of the reassembly involved putting the pistons back in the crankcase. Insert the number two and three pistons into their respective cylinders from the top of the block. Then the connecting rods of the pistons had to be bolted to the crankshaft seated in the engine. Following two and three the same procedure was taken with pistons one and four in their respective cylinders. Tools: A 3/8 drive with a 10mm socket. Difficulty: 10

Pistons: The pistons being inserted into their respective cylinders within the upper half of the crankcase.

Step VI

Connecting Rods: The following step of the reassembly involved securing the connecting rods to the crankshaft. the connecting rods needed to be properly aligned with the crankshaft. Then the lower half of the rods fitted around the journals securely. Followed by the rod fasteners being tightly secured, holding the rods in place. Tools: A 3/8 drive with a 8mm socket. Difficulty: 23

Connecting Rods: The rods are now connected to the engines crankshaft within the crankcase.

Step VII

Crankcase: The following step of the reassembly connecting the two halves of the crankcase together. Mounted the upper half of the crankcase was mounted to the to the lower half, containing the internal components in their respective places. Next everything need to be lined up to make sure proper fitting of the two halves together. Then the halves had to be bolted together, completing the assembly of the crankcase. Tools: A 3/8 drive with a 10mm socket. Difficulty: 18

Crankcase: With the components all in the crankcase it can now be fastened together.

Step VIII

Head Gasket: The head gasket then needed to be placed in its proper location on top of the head. Placed gasket in between combustion chamber and the head. Tools: None Difficulty: 4

Head Gasket: The head gasket is placed on the top of the crankcase.

Step IX

Starter: The following step of the reassembly involved the starter being connected to the crankcase. Insert starter into its respective housing. Fasten the starter to the back of the crankcase with two 8 mm bolts. Tools: A 3/8 drive with a 8mm socket. Difficulty: 8

Starter: After the crankcase was assembled, the starter could now be fastened.

Step X

Clutch Cover: The following step of the reassembly involves securing the clutch cover onto the crankcase, to finish the clutch assembly. Bolted the cover over the clutch basket using ten 10mm bolts. Tools: A 3/8 drive with a 10mm socket. Difficulty: 15

Clutch Cover: With the case completed, the clutch cover could now be fastened.

Step XI

Alternator: The following step of the reassembly involves attaching the alternator to the crankcase, as well as the its cover. Placed the cover onto the crankcase and made sure it was properly seated. Fastened the cover with nine 8mm bolts next to the flywheel. Tools: A 3/8 drive with a 8mm socket. Difficulty: 13

Alternator: After the crankcase was assembled, now the alternator and cover could be fastened.

Step XII

Camshafts: The following step reseated the camshafts within the head. Placed camshafts into respective places within the head Made sure the lobes were properly positioned with respect to the position of the valves. Tools: None Difficulty: 5

Camshafts: The camshafts are now seated in the head in their proper positions.

Step XIII

Camshaft Covers: The following step of the reassembly secured the camshaft covers onto the camshaft seats. Placed camshaft covers over the camshafts inside the head and made sure they were secure. Next group 13 bolted ten, 8mm bolts for each cover. Tools: A 3/8 drive with a 10mm socket. Difficulty: 17

Camshaft Cover: With the camshafts in place, the covers can be bolted down to secure the camshafts.

Step XIV

Spark Plugs: This step secured the spark plugs within the head. Placed the spark plugs into each of the four holes in the cylinder head. They were then fastened with a spark plug socket securely in place. Tools: A 3/8 drive with a 5/8 inch socket. Difficulty: 8

Spark Plugs: The spark plugs could then be secured in their respective places within the head.

Step XV

Valve Cover: The following step of the reassembly attached the valve cover to the head. Place cover on the cylinder head covering the camshafts. Secure the valve cover by fastening six, 10 mm bolts. Tools: A 3/8 drive with a 10mm socket. Difficulty: 14

Valve Cover: The valve cover and gasket could then be fastened to complete the head.

Step XVI

Timing Chain: The timing chain was now fitted around the camshafts as well as the crankshaft. Remove camshaft sprockets and timing chain sprocket. Feed tensioners into the side of engine block. Feed timing chain into side of engine block via the crankcase. Connect timing chain to timing chain sprocket and one of the camshaft sprockets. Bolt camshaft sprockets back on and turn sprockets to allow timing chain to be fitted properly. Tools: A 3/8 drive with a 10mm and 14mm socket. Difficulty: 21

Timing Chain: The timing chain could then be routed through the crankcase and head.

Step XVII

Oil Pan: This step connected the oil pan to the completed crankcase. Make sure the gasket is in the oil pan securely. Fasten the oil pan bolts accordingly. Tools: A 3/8 drive with a 10mm socket. Difficulty: 18

Oil Pan: The oil pan and its gasket were now secured to the bottom of the crankcase.

Step XVIII

Carburetor: The following step of the reassembly involved rebuilding the carburetors and attaching them to the engine. The respective components of the carburetors need to be reassembled to the state of each separate carburetor. Next a rod needs to be inserted through the bracket and guide, this needs to be done it two places to ensure that all four carburetors will be securely in place. The carburetor assembly should then be screwed into the intake manifold start of the air box to help with the later steps. Tools: A 3/8 drive with a 10mm socket. A 10mm open ended wrench. A Philips head screwdriver. A rubber mallet. Difficulty: 125

Carburetor: The carburetors were then put back together and prepared to be fastened to the head.

Step XIX

Air Box: This step involved the separate components of the air box being reassembled. first the lower half of the air box needed to be secured to the engines intake manifold. Next the filter housing along with the filter could be screwed into the lower half of the air box,now connected to the manifold. With the air box top left, make sure both intake hoses are securely fitted within the places, and screw the air box top into the rest of the air box assembly. Tools: A Philips head screwdriver. Difficulty: 20

Air Box: The air box components were then reassembled.

Step XX

Final: The following step was the last, making sure the air box was secured to the carburetors. The air box needs to be properly aligned with all four carburetors, this should be quite easy if steps were followed from XVIII. Once this is complete the carburetor/ air box assembly can be attached to the head, completing the engine rebuild. Tools: A Philips head screwdriver. Difficulty: 22

Honda Engine: With the air box completed and fastened to the engine, the Honda CBR600 F2 was now fully assembled.

Note: Following these steps, group 13 was able to successfully put the Honda Motor back to its original state. These steps should be followed carefully when reassembling the Honda CBR600 F2 motor. If there are any discrepancies or question on certain components please refer to the product evaluation page for pictures and component specifics.

Assembly Summary

Product Assembly

The following is a summary of how Honda originally assembled the motor in the early 90's in contrast to the procedures that group 13 took during gate four.

The original assembly for the 1994 Honda cbr600f2 engine was done in the following manner. The engine works its way through an assembly line where the components and subsystems are attached in a predetermined manner. The engine starts its assembly with just the block, and the engine components are put in place as it progresses through the line. First, the crankshaft is bolted to the bottom of the block so that the pistons can be fed through the top of the cylinders. When the pistons are in the cylinders, the crank arms are bolted on the crankshaft to allow movement. Next, the oil pan is bolted on the bottom of the engine block to ensure the crankshaft is protected as it works its way through the rest of assembly. The series of gears that make up the transmission are assembled separately, and then added to the transmission area of the block. When these gears are in place, the clutch basket (which was also assembled separately) is connected to the end of the transmission shaft. The top of the transmission is then bolted on the block to complete the transmission assembly. Since the cylinder head is a high tolerance subsystem, it is assembled separately from the assembly line and bolted to the top of the engine block as a whole. When assembling the cylinder head, the valves must be set in place with the valve springs on top, and then the valves are connected to the springs using two small pins. After the cylinder head is bolted on the block, the timing chain fed into the engine block with the chain tensioner from the crankshaft spindle up to the top of the cylinder head. The camshafts are then bolted into place while wrapping the timing chain around the sprockets of the camshafts. The valve cover is then bolted on over the cylinder head covering the camshaft assembly. The carburetor’s are another complex subsystem and are assembled at a separate time. When they are brought to the assembly line, they are bolted to the intake side of the cylinder head. The final part of assembly is attaching the air filter/ air box to the top of the engine via the carburetor system. When the air box is attached, the assembly is complete and ready for installation.

Comparison

The following summarizes the dissection of the Honda motor and the reassembly performed by group 13.

For the most part, the assembly of the engine used the same procedure for disassembly, only in reverse order. During disassembly, we started by disconnecting the air box, carburetors, cylinder head, etc. and finished with the transmission. When we started to reassemble the engine, we started with the transmission assembly and worked our way through using the same process ending with the carburetors and air box. The only portion of reassembly that differed from disassembly is the introduction of the pistons into the cylinder. The fact that the piston rings need to expand in the cylinder makes it difficult to keep the rings compressed while sliding the pistons into place using a tool called a ring compressor. Since our group did not have this tool, we were able to work around this procedure due to the fact that the piston rings were not originally with the pistons. The reassembly of the engine was completed in a relatively quick manner by successfully adding each component the same way that they came out.

Design Revisions

These following revisions contain changes that could be made to the Honda motor on the system level. These consist of major changes affecting performance and reliability as well as other important aspects regarding the engine.

One

The angle of the cylinders in relation to the incoming air.

When changing the angle of the cylinders, this will allow for a smoother flow of air travel going from the intake to the cylinders. When the air flow is subjected to a higher degree angled junction, it creates turbulence in the flow and can somewhat restrict performance. With this minimal change of the angle, the air flow will have a more linear path for air flow, thus creating a slight increase in performance. Changing the angle of the cylinders has a societal impact because of the improved performance of the engine as a whole. With increased engine performance, the popularity of the product will be increased within the target audience. Also, with an increased air flow the engines efficiency will be slightly higher. With a more efficient engine the product will operate in such a way that more beneficial when dealing with environmental concerns.

Two

Having the transmission housing detachable from the engine block.

This design revision is directed towards the ability to remove the transmission assembly from the engine block. This revision will allow users to slide the entire transmission assembly out through the side of the block. In order to make this design effective, the transmission assembly will be enclosed in a compact casing, the casing will be resting on sliders that will allow the entire casing to be removed easily. This casing will be bolted to the engine block to ensure the transmission does not slide during operation. This design is an excellent way to increase serviceability of the product. This design consideration addresses some societal concerns in the way that the transmission is improved for the people who work with repairing motorcycle transmissions.

Three

Econ Mode

With the introduction of econ mode to the engine, the engine will now be able to run more efficiently at the discretion of the user. With econ mode enabled the engine will have the ability to shut down a cylinder, as well as adjust the timing of the engines firing order. The efficiency of the engine will be greatly increased when running in econ mode because when dropping one cylinder the amount of fuel used for that cylinder will be saved. This feature will be an excellent economic revision because of the amount of money being saved with increased fuel economy. Also, it is more environmental friendly due to the fact that it is producing fewer emissions.