Valve Stem And Condition - Suzuki DR350 Service Manual

NOTE:
The valve seat contact area mus t be inspected alter each
cut.
1 . In sert wi th a s light rotation, the solid pilot that gives a
snug fit. The shou lder on the pilot should be about 10
mm
(0.39
in) from the va lve guide.
2 . Using th e 45 0 cutter. deseale and clea nup the sea t with
one or two turns.
3 . Inspect the seat by the previous seat width measurement
procedu re. If the sea t is pitted or burned, additional sea t
conditioning with the 4 5° c utter is required .
CAUTION :
Cut the minimum amount necessary from the seat to pre·
vent the possibility of the valve stem becoming too close
to the rocker arm for correct valve contact angle .
If the con tac t area is too low or too narrow, u se the 45 0
cu tter to raise and widen the contac t area. If the contac t
area is too high or to o wide, u se the 15
0
cutter to lower
and narrow the con tac t area .
4 . After the desired sea t positon and width is achieved, use
the 4 5 0 cu tter ve ry lightly to clean up any burrs c au sed
by the previous cutting operations. DO NOT use lapping
compound aher the final cu t is made. The finished valve
seat should have a velvety smooth finish and not a high-
ly polished or sh iny fin ish. This will provide a soh sur-
f ace for the final seating o f the valve which will occu r
during the first few seconds of engine operation .
S . Clean and assemble the head and valve co mpon ents. Fill
the intake and exhaust ports with gasolin e to check for
leaks.
If
any leaks occur, inspect the valve seat and face
for burrs or ot her things that cou ld prevent the valve from
sealing .
WARNING :
Always u se extreme caution when handling gasoline.
NO TE:
Be
sure to adjust the valve clearance after reassembling the
engme.
VALVE STEM END CONDITION
lnspec the valve stem end face for pitting and wear. If pit-
ting or wear of the stem end face are present, the valve stem
end may be resurfaced, providing that the length
<D
will not
be reduced to less than 1.8 mm (0.07 in) . If thi s length be-
comes less than 1 .B mm (0.07 in). the valve must be
repl aced . Aher installing a valve whose stem end has been
ground o ff as above , check to ensure that the face
@
o f
t he valve stem end is above the co tters
@' ,
COnl ltC:1 e ree 100 lo w
end 100 netr o w o n face
of lI'al..,,,
Contac t a rea 100 high
e nd 100 wide on lece of
"'81 ..,e
ENGINE 3·20
Cf a
, ill
,.'
.
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