Yamaha MZ250 2012, Supplementary Service Manual

Page: 26 / 42

4-5
SPEC
MAINTENANCE SPECIFICATIONS
Model name:
MZ250 MZ300
Model code number:
7KBJ 7KBN 7VBJ 7VBN
Valve: mm (in)
Head diameter “A” IN 27.9–28.1
(1.0984–1.1063)
31.9–32.1
(1.2559–1.2638)
EX 26.9–27.1
(1.0591–1.0669)
28.9–29.1
(1.1378–1.1457)
Stem diameter “B” IN
5.948–5.963 (0.2342–0.2348)
EX
5.940–5.955 (0.2339–0.2344)
<Limit> IN
5.918 (0.2330)
EX
5.910 (0.2327)
Stem length “C” IN
90.5 (3.563) 90.0 (3.5433)
EX
91.1 (3.5866) 90.3 (3.5551)
Valve face contact width “D”
IN
0.7–0.9 (0.0276–0.0354)
EX
0.7–0.9 (0.0276–0.0354)
<Limit> IN
1.6 (0.063)
EX 1.6 (0.063)
Valve seat contact width IN
0.7–0.9 (0.0276–0.0354)
EX
0.7–0.9 (0.0276–0.0354)
<Limit> IN
1.6 (0.063)
EX
1.6 (0.063)
Valve seat width IN
0.7–0.9 (0.0276–0.0354)
EX
0.7–0.9 (0.0276–0.0354)
Valve margin thickness IN
1.0–1.4 (0.0394–0.0551)
EX 1.0–1.4 (0.0394–0.0551)
Valve stem runout limit
0.01 (0.0004)
“
θ
”
90°
Valve guide
Guide inside diameter
IN
6.000–6.012 (0.2362–0.2367)
EX
6.000–6.012 (0.2362–0.2367)
Stem to guide clearance IN
0.037–0.064 (0.0015–0.0025)
EX
0.045–0.072 (0.0018–0.0028)
Valve clearance (cold) IN 0.08–0.12 (0.0031–0.0047)
EX
0.08–0.12 (0.0031–0.0047)
Push rod: mm (in)
Runout limit
0.15 (0.0059)