Description: Engine typeEngine model
Displacement
Bore x Stroke
Compression Ratio
Starting system
Ignition system
Lubrication system |
Air cooled 4-stroke, forward incline, single, S.O.H.C.2J2499 cc (30.45 cu. in.)87 x 84 mm (3.425 x 3.307 in)
9.0 : 1
Primary kick starter
C.D.I.
Dry sump, trochoidal pump |
Cylinder Head: Combustion chamber typeCombustion chamber volume
(with BP7ES or N-7Y)
Head gasket thickness |
Hemispherical62.4 cc (3.81 cu. in.)1.0 mm (.039 in) |
Camshaft: Cam drive typeCamshaft bearing type (left)
Camshaft bearing type (right)
Cam chain type and No. of links |
Drive chain (right side drive)6005C36005C3 (with groove)BF05M, 106L |
Cam dimensions:A (Cam Height) IN.A (Cam Height) EX.B (Base circle) IN.B (Base circle) EX.
C (Cam lift) IN.
C (Cam lift) EX.
Camshaft run out limit
Valve timing:
Intake open
Intake close
Duration
Exhaust open
Exhaust close
Exhaust duration
Valve overlap
|
required <allowable>39.23 +or- .05 mm <39.08 mm>(1.5445 +or- .0020 in <1.5386 in>)39.25 +or- .05 mm <39.10 mm>
(1.5453 +or- .0020 in <1.5394 in>)
32.23 +or- .05 mm <32.08 mm>
(1.2689 +or- .0020 in <1.2630 in>)
32.28 +or- .05 mm <32.08 mm>
(1.2709 +or- .0020 in <1.2630 in>)
7.225 mm (.2844 in)
7.253 mm (.2856 in)
<0.1 mm (.0039 in)>BTDC 44 deg
ABDC 68 deg
292 deg
BBDC 76 deg
ATDC 36 deg
292 deg
80 deg |
Rocker arm and rocker shaft:Rocker arm bearing dia. (I.D.)Rocker arm shaft dia. (O.D.)Clearance |
required <allowable>12.00~12.02 mm <12.05 mm>(.4724~.4732 in <.4744 in>)
11.98~11.99 mm <11.96 mm>
(.4714~.4720 in <.4709 in>)
.01~.04 mm <.11 mm>
(.0004~.0016 in <.0043 in>) |
Valve, valve seat and valve guide:Valve clearance (cold): IN.Valve clearance (cold): EX.
No. of valves per cylinder:Valve head dia. (A): IN.
Valve head dia. (A): EX.
Valve face width (B): IN.
Valve face width (B): EX.
Valve seat width (C): IN.
Valve seat width (C): EX.
Valve margin thickness (D): IN.
Valve margin thickness (D): EX.
Valve stem outside dia.: IN.
Valve stem outside dia.: EX.
Valve guide inside dia.: IN.
Valve guide inside dia.: EX.
Valve stem to guide clearance: IN.
Valve stem to guide clearance: EX. |
required <allowable>.10 mm (.0039 in).15 mm (.0059 in)
2 pcs47 mm (1.85 in)
39 mm (1.54 in)
2.12 mm (.0835 in)
2.12 mm (.0835 in)
1.3 mm (.051 in)
1.3 mm (.051 in)
1.3 mm (.051 in)
1.3 mm (.051 in)
7.97~7.99 mm (.3138~0.3146 in)
7.96~7.97 mm (.3134~0.3138 in)
8.01~8.02 mm (.3154~0.3157 in)
8.01~8.02 mm (.3154~0.3157 in)
.02~.04 mm <.08 mm>
(.0008~.0016 in <.0031 in>)
.04~.06 mm <.1 mm>
(.0016~.0024 in <.0039 in>) |
Valve springs:Free length: InnerFree length: Outer
Spring rate: InnerSpring rate: Outer
Installed length (valve closed): Inner
Installed length (valve closed): Outer
Installed pressure (valve closed): Inner
Installed pressure (valve closed): Outer
Compressed length (valve open): Inner
Compressed length (valve open): Outer
Compressed pressure (valve open): Inner
Compressed pressure (valve open): Outer
Wire diameter: Inner
Wire diameter: Outer
Winding outside diameter: Inner
Winding outside diameter: Outer
Tilt limit from vertical: Inner
Tilt limit from vertical: Outer |
required <allowable>45.3 mm <43.9 mm> (1.783 in <1.728 in>)44.6 mm <43.3 mm> (1.756 in <1.703 in>)
K1= 1.67, K2 = 2.12 [kg/mm]
(K1 = 93.5, K2 = 119 [lb/in])
K1 = 3.60, K2 – 4.63 [kg/mm]
(K1 = 202, K2 = 259 [Ib/in])
38.0 mm (1.496 in)
40.0 mm (1.575 in)
12.2 kg (26.9 lb)
16.4 kg (36.2 lb)
28.0 mm (1.102 in)
30.0 mm (1.181 in)
33.4 kg (73.6 lb)
62.7 kg (138.2 lb)
3.1 mm (.122 in)
4.4 mm (0.173 in)
23.4 mm (.921 in)
32.9 mm (1.295 in)
1.97 mm (.0776 in)
1.97 mm (.0776 in) |
Cylinder:MaterialBore sizeTaper limit
Out Of round limit |
required <allowable>Aluminum alloy with cast iron sleeve87.00 ~87.02 mm <87.1 mm>
(3.4252 ~3.4260 in <3.429 in>)
<.05 mm> (<.0020 in>)
<.01 mm> (<.0004 in>) |
Piston: Piston clearancePiston clearance measuring position
(from piston skirt bottom)
Piston pin bore sizePiston pin outside diameter
Piston pin length
Over size piston diameter: 1 st
Over size piston diameter: 2nd
Over size piston diameter: 3rd
Over size piston diameter: 4th |
required <allowable>.050 ~ .055 mm (.0020 ~ .0022 in)7.2 mm (.283 in)20.00 ~ 20.02 mm <20.08 mm>
(.7874 ~ .7882 in <.7905 in>)
19.99 ~ 20.00 <19.96 mm>
(.7870 ~ .7874 in <.7858 in>)
75 mm (2.95 in)
87.25 mm (3.4350 in)
87.50 mm (3.4449 in)
87.75 mm (3.4547 in)
88.00 mm (3.4646 in) |
Piston ring: Piston ring design: Top ringPiston ring design: 2nd ring
Piston ring design: Oil ring
Ring end gap (installed): Top ringRing end gap (installed): 2nd ring
Ring end gap (installed): Oil ring
Ring groove side clearance: Top ring
Ring groove side clearance: 2nd ring
Ring groove side clearance: Oil ring
Over size piston ring: Ist
Over size piston ring: 2nd
Over size piston ring: 3rd
Over size piston ring: 4th |
required <allowable>Plain ringPlain ring
Oil ring with expander
.3 ~ .5 mm <0.8 mm>
(.012 ~ .020 in <.030 in>)
.3 ~ .5 mm <.8 mm>
(.012 ~ .020 in <.031 in>)
.2 ~ .9 mm <1.0 mm>
.04 ~ .08 mm <.15 mm>
(.0016 ~ .0031 in <.0059 in>)
.03 ~ .07 mm <.15 mm>
(.0012 ~ .0028 in <.0059 in>)
N.A.
87.25 mm (3.4350 in)
87.50 mm (3.4449 in)
87.75 mm (3.4547 in)
88.00 mm (3.4646 in) |
Big end bearing: TypeInside dia. x outside dia. x width
Needle dia. x quality |
Needle bearing34 x 42 x 24 mm (1.34 x 1.65 x .94 in)IKO 4 mm (.16 in) x 18 pcsKOYO 4 mm (.16 in) x 17 pcs. |
Crankshaft: Crankshaft assembly width (F)Crankshaft deflection ( D )
Connecting rod large end side clearance (C)
Connecting rod small end deflection (P)Crank pin outside dia. x length
Crank bearing type; Left
Crank bearing type; Right
Crank oil seal type: Left
Crank oil seal type: Right |
required <allowable>74.95 ~ 75.00 mm (2.9508 ~ 2.9528 in)<.03 mm (.0012 in) or less>
.35 ~ .65 mm (.0138 ~ .0256 in)
.8 ~ 1.0 mm <2.0 mm>
(.0315 ~ .0394 in <0.079 in>)
34 x 74 mm (1.34 x 2.91 in)
6306 SH2-9-C4
6307 SH2-9-C4 with special heat treatment
SD-30-60-6
S-14-25-5.5 special |
Clutch:Clutch typeClutch push mechanism
Primary reduction ratio and method
Primary reduction gear back lash number
Primary drive gear back lash number
Primary driven gear back lash number
Friction plate: Thickness/quantityClutch plate: Thickness/quantity
Clutch plate: Warp limit
Clutch spring: Free length/quantity
Clutch spring: Spring set weight
Clutch spring: Spring constant
Clutch housing thrust clearance
Push rod bending limit
Push lever axle: Bearing type and size
Push lever axle: Oil seal type and size |
required <allowable>Wet, multiple disc typeInner push, cam axle type
77/30 (2.566), spur gear
148 ~ 150
21.79 +0 -.04 mm (4 Teeth)
52.71 +0 -.04 mm (9 Teeth)
2.8 mm <2.5 mm> /8 pcs.
(.110 in <.098 in> /8 pcs.)
1.2 mm /7 pcs. (.047 in /7 pcs.)
<.05 mm (.0020 in)>
41.2 mm <40.0 mm> /6 pcs.
(1.622 in <1.575 in> /6 pcs.)
19.8 x 6 kg/25 mm (43.7 6 lb/.984 in)
1.22 kg/mm (68.3 lb/in)
.10 ~ .21 mm (.004 ~ .008 in)
<.2 mm (.0079 in) or less>
Needle bearing (17-21.5-15) x 2 pcs.
SD-17-28-6 |
Transmission: TypeGear ratio: 1st
Gear ratio: 2nd
Gear ratio: 3rd
Gear ratio: 4th
Gear ratio: 5th
Bearing type: Main axle (Left)
Bearing type: Main axle (Right)
Drive axle (Left)
Drive axle (Right)
Drive axle (Left)
Secondary reduction ratio and method |
Constant mesh. 5 speed33/14 (2.357)28/18 (1.555)25/21(1.190)
22/24 (0.916)
21/27 (0.777)
Needle bearing (20-32-12)
4205
6305 special
Needle bearing (20-36-12)
SD-35-62-10
44/16 (2.750), chain |
Shifting mechanism: Operation systemShifting type
Oil seal type: Change lever |
Return type, left foot operationGuide bar type, cam drum systemSDO-14-24-6 |
Kick starter: TypeOil seal type Kick axle |
Ratchet typeSD-25-35-7 |
Compression release: TypeLever free play
Oil seal type |
Manual, wire linked cam axle type2 mm (.079 in)SD-12-17-2.5-2NR |
Air cleaner: Type/quantity |
Dry foam rubber / l pc. |
Carburetor: Type and manufacturerI.D. mark
Main jet (M.J.)
Airjet (A.J.)
Jet needle: Clip position (J.N.)
Needle jet (N.J.)
Cutaway (C.A.)
Pilot jet (P.J.)
Mixture screw turns out
Starter jet (G.S.)
Float height
Idling engine speed |
VM34SS MIKUNI2J200#300#80
6FL25-2
P-8
3.5
#25
Preset
#50
23.5 +or- 1 mm (.925 +or- .039 in)
1100 r/min |
Lubrication: Transmission gear and engine sump oilQuantity
Type engine oil
Oil pump: Type
Oil pump: Housing inside diameter
Oil pump: Housing depth (delivery)
Oil pump: Housing depth (scavenger)
Oil pump: Rotor diameter
Oil pump: Rotor thickness (delivery)
Rotor thickness (scavenger)
Outer rotor and housing clearance
Side clearance
Tip clearance
Check valve opening pressure
By-pass valve opening pressure
Oil cleaner type |
required <allowable>Total amount: 2.4 lit (2.5 US.qt) (2.11 Imp. qt)Periodic oil change: 2.0 lit (2.1 US.qt) (1.76 Imp. qt)
Exchange with oil filter: 2.1 lit (2.2 US.qt) 1.85 IMP.qt)
Yamalube 20W / 40 motor oil or equivalent
Trochoidal pump
40.65 ~ 40.68 mm <40.85>
(1.6004 ~ 1.6016 <1.6083 in>)
4.03 ~ 4.06 mm <4.09 mm>
(.1587 ~ .1598 in <.1610 in>)
18.03 ~ 18.06 mm <18.09 mm>
(.7098 ~ .7118 in <0.7122 in>)
40.53 ~ 40.56 mm <40.50 m>
(1.5957 ~ 1.5968 in <1.5945 in>)
3.98 ~ 4.00 mm <3.95 mm>
(.1567 ~ .1575 in <.1555 in>)
17.98 ~ 18.00 mm <17.95 mm>)
.09 ~ .15 mm <.35 mm>
(.0035 ~ .0059 in <.0138 in>)
.03 ~ .08 mm <0.14 mm>
(.0012 ~ .0031 in <.0055 in>)
.07 ~ .12 mm <.35 mm>
(.0028 ~ .0047 in <.00138 in>)
.18 kg/cm2 (2.56 lb/in2)
1.0 kg/cm2 (14.2 lb/in2)
Paper type |