Yamaha FT50C Service Manual page 248

TRBL
SHTG
(Ignition system)
Check the ignition spark gap using the spark gap tester.
Out of specifi-
cation?
Yes
Replace the spark plug.
(Compression pressure)
Check that there is no secondary air intake on the contact surfaces of
the intake manifold and crankcase.
Is there air
intake?
No
Check the compression pres-
sure of the combustion chamber.
9-5
Troubleshooting
No
Check the ignition system out-
put peak voltage.
Yes
Replace the respective seals.
62Y5A11