Yamaha MTN850-A 2017, Service Manual, Page: 515 / 560

ELECTRICAL COMPONENTS
8-158
Refer to “CHECKING AND CLEANING THE
THROTTLE BODIES” on page 7-8.
4. Check:
•
Engine idling speed
Start the engine, warm it up, and then mea-
sure the engine idling speed.
EAS30552
CHECKING AND CHARGING THE BATTERY
WARNING
EWA13290
Batteries generate explosive hydrogen gas
and contain electrolyte which is made of poi-
sonous and highly caustic sulfuric acid.
Therefore, always follow these preventive
measures:
• Wear protective eye gear when handling or
working near batteries.
• Charge batteries in a well-ventilated area.
• Keep batteries away from fire, sparks or
open flames (e.g., welding equipment,
lighted cigarettes).
• DO NOT SMOKE when charging or han-
dling batteries.
• KEEP BATTERIES AND ELECTROLYTE
OUT OF REACH OF CHILDREN.
• Avoid bodily contact with electrolyte as it
can cause severe burns or permanent eye
injury.
FIRST AID IN CASE OF BODILY CONTACT:
EXTERNAL
• Skin — Wash with water.
• Eyes — Flush with water for 15 minutes and
get immediate medical attention.
INTERNAL
• Drink large quantities of water or milk fol-
lowed with milk of magnesia, beaten egg or
vegetable oil. Get immediate medical atten-
tion.
NOTICE
ECA13661
• This is a VRLA (Valve Regulated Lead Acid)
battery. Never remove the sealing caps be-
cause the balance between cells will not be
maintained and battery performance will
deteriorate.
• Charging time, charging amperage and
charging voltage for a VRLA (Valve Regu-
lated Lead Acid) battery are different from
those of conventional batteries. The VRLA
(Valve Regulated Lead Acid) battery should
be charged according to the appropriate
charging method. If the battery is over-
charged, the electrolyte level will drop con-
siderably. Therefore, take special care
when charging the battery.
TIP
Since VRLA (Valve Regulated Lead Acid) bat-
teries are sealed, it is not possible to check the
charge state of the battery by measuring the
specific gravity of the electrolyte. Therefore, the
charge of the battery has to be checked by mea-
suring the voltage at the battery terminals.
1. Remove:
• Rider seat
Refer to “GENERAL CHASSIS (1)” on page
4-1.
2. Disconnect:
• Battery leads
(from the battery terminals)
NOTICE
ECA13640
First, disconnect the negative battery lead
“1”, and then positive battery lead “2”.
3. Remove:
•
Battery
Refer to “GENERAL CHASSIS (1)” on page
4-1.
4. Check:
•
Battery charge
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect a digital circuit tester to the battery
terminals.
TIP
•
The charge state of a VRLA (Valve Regulated
Lead Acid) battery can be checked by measur-
ing its open-circuit voltage (i.e., the voltage
when the positive battery terminal is discon-
Engine idling speed
1100–1300 r/min
•
Positive tester probe

Positive battery terminal
•
Negative tester probe

Negative battery terminal
1 2