Yamaha MZ360, Service Manual

Page: 137 / 178

ENGINE SPEED DOES NOT INCREASE
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TR
OUBLESHOO
TING
ENGINE SPEED DOES NOT INCREASE
No. Checking steps Possible remedy
1 Check the spark plug for dirt and check the spark plug gap. Clean, adjust, or replace the spark plug.
2 Check the air filter element for dirt. Clean.
3
Check the compression pressure.
(Refer to “MEASURING THE COMPRESSION PRES-
SURE” on page 3-1)
Too high:

Decarbonize the combustion chamber if
there is carbon deposits.
Too low:

Next checking steps.
4
Check the valve clearance.
(Refer to “ADJUSTING THE VALVE CLEARANCE” on
page 2-12)
Adjust the valve clearance.
5
Check the valve face and valve seat for wear.
(Refer to “VALVE” on page 3-37) Resurface or replace the valve face and
valve seat.
6
Check if the marks on the crankshaft, camshaft, and bal-
ancer shaft are aligned.
(Refer to “INSTALLING THE VALVE LIFTER, BALANCER
SHAFT, AND CAMSHAFT” on page 3-50)
Correct.
7
Check if there is seizure, wear, or damage on the piston,
piston ring, or cylinder.
(Refer to “PISTON, CAMSHAFT, CRANKCASE, AND
CRANKSHAFT” on page 3-44)
Rebore or replace.
8
Check if the main passages, such as the main jet in the car-
buretor, are clogged.
Clean the parts.
9
Check if there is air suction from the carburetor joint, gas-
ket, or throttle shaft.
• Tighten the carburetor nuts securely.
• Replace the carburetor joint or gasket
with a new one.