Abstract: A method of controlling the electric current of a linear solenoid valve by performing pulse width modulation on a coil current for energizing a linear solenoid of the linear solenoid valve to adjust the hydraulic pressure of a working oil in a hydraulic clutch for transmitting and interrupting the rotational drive power from a power source to a drive wheel of a vehicle. The method includes setting the period of the pulse width modulation to a shorter value as the degree to which the hydraulic clutch is engaged increases from a disengaged state thereof. Here, the period of the pulse width modulation may be set in accordance with the variation of a duty ratio depending on the hydraulic pressure corresponding to the degree to which the hydraulic clutch is engaged.

Abstract: A method of controlling the electric current of a linear solenoid valve by performing pulse width modulation on a coil current for energizing a linear solenoid of the linear solenoid valve to adjust the hydraulic pressure of a working oil in a hydraulic clutch for transmitting and interrupting the rotational drive power from a power source to a drive wheel of a vehicle. The method includes setting the period of the pulse width modulation to a shorter value as the degree to which the hydraulic clutch is engaged increases from a disengaged state thereof. Here, the period of the pulse width modulation may be set in accordance with the variation of a duty ratio depending on the hydraulic pressure corresponding to the degree to which the hydraulic clutch is engaged.

Abstract: A power unit for a motorcycle having a continuously variable transmission, which is housed in a transmission chamber inside a engine body and which accomplishes stepless changes in the transmission of power from a drive pulley shaft to a driven pulley shaft by changing the effective diameter with which a belt actually wraps around each of the drive and the driven pulleys. An input clutch is set between a crankshaft and a drive pulley and is provided on the drive pulley shaft. A starter clutch is set between a driven pulley shaft and a rear wheel and is provided on the driven pulley shaft. The switching between the engagement and disengagement of one of the input clutch and the starter clutch is hydraulically controlled. Meanwhile, the switching between the engagement and disengagement of the other one of the input clutch and the starter clutch is mechanically controlled.

Abstract: A power unit for a motorcycle having a continuously variable transmission, which is housed in a transmission chamber inside a engine body and which accomplishes stepless changes in the transmission of power from a drive pulley shaft to a driven pulley shaft by changing the effective diameter with which a belt actually wraps around each of the drive and the driven pulleys. An input clutch is set between a crankshaft and a drive pulley and is provided on the drive pulley shaft. A starter clutch is set between a driven pulley shaft and a rear wheel and is provided on the driven pulley shaft. The switching between the engagement and disengagement of one of the input clutch and the starter clutch is hydraulically controlled. Meanwhile, the switching between the engagement and disengagement of the other one of the input clutch and the starter clutch is mechanically controlled.

Abstract: A process for producing a heat-sensitive recording material superior in the stability of both base surface and recorded image, characterized by adjusting pH of a heat-sensitive coating suspension of 5 to 12.

Abstract: The present invention provides a heat sensitive recording material which is less in fog in background area and has superior color toning effect with high image storage stability which contain a fluoran compound represented by the following formula in addition to an aromatic isocyanate compound and an imino compound having at least one >C.dbd.NH group which forms color upon application of heat: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 each represents a hydrogen atom, a lower alkyl group, a cyclohexyl group or an allyl group and R.sub.4 and R.sub.5 each represents a hydrogen atom, a lower alkyl group, a phenyl group, a cyclohexyl group or an aralkyl group. This heat sensitive recording material may further contain a heat fusible substance and/or a phenol compound to further improve heat responsivity or anti-fogging properties of background portion.