A. Reed Valve Locations
The T2500 engine relies on two steel reed
valves as a key element of its C4 technology.
The intake reed valve is mounted on the back
(engine) side of the insulator block. The
crankcase/boost chamber reed valve is
mounted beneath the crankcase in the boost
chamber.
B. Accessing Reed Valves
To inspect intake reed valve, air filter cover,
filter element, filter base and carburetor must
first be removed. Detach insulator block. Reed
valve is mounted on inside surface.
To inspect crankcase/boost chamber reed
valve, fuel tank and tank guard must first be
removed. Detach boost chamber cover on
bottom of crankcase. Reed valve is mounted
to base of boost chamber.
C. Reed Valve Inspection
Trapped debris, or damage that prevents
proper reed valve operation, can affect engine
performance. For example, a faulty intake reed
can cause excessive spit-back and poor
performance. Inspect reed valves for:
Flatness (maximum gap = .004" - .012"
(0.1 mm - 0.3 mm )
Cracking or warping
Discoloration or corrosion
Debris accumulation
Replace reed valves that exceed gap
specification or those with indications of
warping, discoloration, corrosion or debris
build-up.
D. Replacing Reed Valves
Intake reed valve/insulator block is a
complete assembly. Parts cannot be replaced
individually.
Crankcase/boost chamber reed valve
components (block, reed, stop) may be
replaced individually.
E. Reed Valve Replacement Interval
Both intake and crankcase/boost chamber
reed valves should be replaced after
400
hours
of operation.
Section
6 Reed Valve Inspection/Replacement
Inspecting &
Replacing
Reed Valves
Intake reed valve is mounted on back (engine)
side of carburetor insulator block. Reed valve/
insulator block must be replaced as a complete
assembly.
Crankcase/boost chamber reed valve is
mounted beneath crankcase. To access,
remove boost chamber cover. Valve, block and
stop may be replaced separately.
Small gap, .004" - .012", between reed block
and petal, is permissible. Boost chamber reed
petal (above) is replaceable as a separate part.
When installing, make sure it aligns with
recessed seat in reed block.
13
.004"
Edition 2• 09/2007
