Yamaha BR250F - Page 39

Trouble
Check point Remedy
Adjustment
Poor performance at Clogged air vent Clean
I Remove
the air vent
pipe,
and
normal speeds
clean.
(Relative troubles)
Clogged or loose main jet Clean and retighten Remove main jet, and blow it out
• Excess fuel consumption
• Poor acceleration
with compressed air.
Overflow Check float and float valve
and clean
Poor performance at high
Starter valve is left open Fully close valve
Return starter lever to its
home
speeds
position.
(Relative troubles)
Clogged air vent Remove and clean
•
Power loss
•
Poor acceleration
Clogged
or loose main jet Clean and retighten
Remove main jet, and clean
with
compressed air, then install.
Clogged fuel
pipe Clean or replace
Dirty fuel tank Clean fuel tank
Air leaking into fuel line Check joint and retighten
Low fuel pump performance Repair pump or replace
Clogged
fuel filter
Replace
Clogged
intake
Check for ice, and remove
Abnormal combustion
Lean mix tu res
Clean
carburetor and adjust
(Mainly backfire)
Dirty carburetor
Clean carburetor
Dirty or clogged fuel pipe
Clean or replace fuel pipe
Overflow
Clogged air vent
Clean
(Relative troubles)
Clogged float valve
Disassemble and clean
Clean
while taking
care
not
to
• Power
idling
scratch valve seat.
•
Poor performance at low,
mid-range, and high
Scraehed or unevenly worn
Clean or replace float valve
Valve seat is press-fitted to body.
speeds
float valve or valve seat
and valve seat
So
body must be replaced if seat is
• Excessive
fuel consump-
damaged.
tion
Broken float
Replace float
• Hard starting
Incorrect float level
If not within the specified
• Power loss
•
Poor acceleration
range,
check the following
parts and replace any
defective part.
• Worn float tang
Replace
float
Replace float assembly.
•
Worn pin
Replace arm pin
• Deformed float arm
Replace
float