Motorcycle Driveline Flashcards
List four purposes of gears:
A. Transmit power
B. Torque Multiplication
C. Change Direction
D. Timing
What is a gear?
A rotating lever.
Define gear ratio:
ratio of Drive to Driven gears
Gear types:
1.Spur, 2.Offset-Spur, 3.Helical, 4.Planetary, 5.Worm, 6. Bevel, and 7.Sector.
Planetary gear:
Used in Starter motors
Gear ratio formula:
Driven / Drive = Gear Ratio
Direct Drive Gear Type
1.000:1 (changes direction/rotation)
Overdrive
Numerically Less than 1.000:1 (10/20=0.500:1)
Underdrive
Numerically more than 1.000:1 (20/10=2.000:1)
Primary Drive:
Crankshaft = Drive Clutch = Driven
Clutch / Crankshaft = Ratio
Transmission:
Main-shaft = Drive
Countershaft= Driven
Countershaft / Main Shaft = Ratio
Final Drive
Transmission = Drive
Rear Wheel = Driven
Rear wheel / Transmission Output = Ratio
Primary Drive Gear Types:
- Chain
- Belt
- Gear
Belt
Alignment is Critical
Gear:
- Crankshaft and Clutch turn opposite directions
2. Helical requires thrust bearings on crankshaft
Purpose of Clutch:
Engage and Disengage power flow.
Manual Clutch
Dry: Sealed from oil
Wet: Partially submerged in oil; dampens engagement and cools
Basket
Splined to nothing, only freewheels on transmission mainshaft
Drive Plates
Turned by basket
Hub
Turns whenever clutch is engaged. Does not turn when disengaged.
Pressure Plate
Transmits spring pressure to drive and driven plates to press them together.
Springs
Force holding parts together
Manual Clutch Release Mechanisms:
1.Rocker Arm, 2.Ball and Ramp, 3.Rack and Pinon, 4.Lever, 5.Cam, 6. Screw, 7. Hydraulic
Powerflow engaged (lever out)
Crankshaft - Basket - Drive Plates - Driven Plates - Hub - Mainshaft
Powerflow disengaged (lever in)
Crankshaft - Basket - Drive plates
Clutch Slippage
Clutch doesn’t transfer 100% of power
Weak Springs (measure free length)
Clutch Drag
Clutch doesn’t fully disengage
Worn release mechanism, warped plates, notched basket or Hub
Centrifugal Clutch
Engagement depends on engine rpm
Variable Ratio Clutch
Also know as continously variable rate transmission (CVT)
Sprag Clutch
Engages in one direction. Slips in the other
What is an advantage of Helical Gear?
Wider
Name four types of chains that are found in Primary Drives.
- Single
- Duplex
- Triplex
- Hyvo
Where is Sprag Clutch used?
In Starter systems
What is a Sprag clutch?
Engages in one direction only
What is significant about the variable ratio clutch?
It’s a clutch and transmission combined.
What type of clutch relies on engine rpm to engage and disengage power flow?
Centrifugal clutch (also known as “semi automatic” transmission)
What is the formula for determining the primary drive ratio?
Clutch / Crankshaft
What is the formula for determining the transmission gear ratio?
Countershaft / Mainshaft
Write the formula for the determining the Final Drive Ratio.
Rear Wheel / Transmission Output = Ratio
What is an advantage of a Spur Gear?
Strong
What type of gear is used when shafts are 90 degrees to each other?
Bevel Gears
What two types of springs are most commonly used to squeeze the clutch plates together?
Coil and Diaphram
What transmits pressure to the disc stack when the clutch is engaged?
Pressure Plate
What is the Hub Splined or fastened to?
Mainshaft
What plate is attached to the Hub
Driven
What plate is attached to and driven by the clutch basket?
Drive
What is the purpose of shock dampers often found on the backs of some clutch baskets?
To absorb peaks in the power flow.
What shaft does the clutch basket rotate (freewheel) on?
Mainshaft
What part of the multi-plate clutch is driven by the engine crankshaft?
Basket.
What are the 5 types of clutches?
1.Manual, 2.Centrifugal, 3.Variable ratio, 4.Sprag, 5.Torque Converter
What is the purpose of the clutch?
Engage and Disengage powerflow
