2026 KPMI Full Catalog V1 - Flipbook - Page 299
YAMAHA WR / YZ 400F / 426F 1998-'02
®
™
™
YAMAHA
Valve Spring Kit • Lightweight Racing
KPMI P/N
Type
Max Valve Lift Installed Height
Seat Pressure
Open Pressure
@ Lift
Intake
.375”
1.105"
39#
85#
.375”
Exhaust
.375”
1.105"
39#
85#
.375”
80-80100
Kit Includes
3
In Titanium Retainers
3
In CrSi Valve Springs
3
In H. T. Steel Basewashers
2
Ex Titanium Retainers
2
Ex CrSi Valve Springs 2
Ex H. T. Steel Basewashers
3
2
In Viton® Seals
Ex Viton® Seals
Valves • White Diamond® • Hard Chrome Stems
Stem Diameter
Tulip
O. L.
Remarks
1.063"
0.1765"
15º
3.320"
Standard
27.00mm
1.063"
0.1765"
15º
3.280"
Standard
28.00mm
1.102"
0.1955”
25º
3.220"
Standard
KPMI P/N
Type
Head Diameter
80-8055H
Intake
27.00mm
80-8056H
Intake
(Center)
80-8057H
Exhaust
Must use Kibblewhite® Lightweight Valve Spring Kits when installing White Diamond™ Valves.
Valve Guides • C630 Bronze
A
B
C
D
E
0.550”
0.580”
0.510”
0.640"
0.430"
0.580”
0.610”
0.580”
0.695"
F
G
Intake
0.1765” 0.3957" / Std.
0.420"
Exhaust
80-80110
+0.002”
80-80112
+0.010”
80-80119
80-80120
0.1955” 0.3957" / Std.
+0.002”
80-80122
+0.010”
80-80129
Use O.E.M. vlave guide seal.
Valve Guide Seal Kits • High Performance
Part Number
Designed for these guide specs
In / Ex Stem
Diameter
O.L
Seal
O.D.
Seal
Style
A
B
C
D
4.5mm
0.331"
0.370"
4
0.321”±0.002”
0.281”
0.120”
0.240”
80-80106
Kit Includes
3
Intake Viton® Seals
2
Exhaust Viton® Seals
Keeper Set • O.E.M. Replacement
KPMI P/N
Style
80-80130
Single
Radius Bead
“D”
“C”
A
E
Type
A
B
C
D
E
Quantity
Intake
0.177"
6.0°
0.186"
0.221”
0.212”
3 Pr.
Exhaust
0.196"
6.5°
0.181"
0.216”
0.270”
2 Pr.
Note : The bead height is referenced from the minor diameter of the keeper to the center of the bead.
281
“B”
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