When the engine is running, the air intake valve is lifting up.
If the valve does not operate properly, check the air intake solenoid valve hoses for leak.
If there are no leaks, check the air intake solenoid valve.

Air Intake Solenoid Valve Unit TestSidestand Installation
Replace the sidestand nut [A] with a new one.
Apply grease to the sliding areas [B].
Tighten the sidestand bolt [C] first, and then the sidestand
nut.
Torque - Sidestand Bolt: 44 N·m (4.5 kgf·m, 32 ft·lb)
Sidestand Nut: 29 N·m (3.0 kgf·m, 21 ft·lb)
Install the spring [D] as sh ...
Electrical Leads
A two-color lead is identified first by the primary color and
then the stripe color. Unless instructed otherwise, electrical
leads must be connected to those of the same color.
Instrument
Use a meter that has enough accuracy for an accurate
measurement. Read the manufacture’s instructions ...
Precautions
1) No need of topping-up
No topping-up is necessary in this battery until it ends its life under
normal use. Forcibly prying
off the seal cap to add water is very dangerous. Never do that.
2) Refreshing charge.
Give refresh charge for 5 to 10 hours with charge current shown in the text
(see ...