SR 500 1978-79

General Specifications

1978 1979
Model: 
I.B.M. No.
Frame I.D. and starting number
Engine I.D. and starting number

2J2
2J2-000101
2J2-000101
2J2-020101
2J2-020101
Dimensions: 
Overall length
Overall width (standard)
Overall height (standard)
Wheel base
Minimum ground clearance

2,105 mm (82.9 in)
835 mm (32.9 in)
1,150 mm (45.3 in)
1,410 mm (55.5 in)
165 mm (6.5 in)
Weight:
Net weight

163 kg (359 lbs)
Performance: 
Climbing ability
Minimum turning radius
Braking distance

30 deg
2,400 mm (94.5 in)
14 m (45.9 ft) at 50km/h (31 mph)

Engine specifications 

Description: 
Engine type
Engine model
Displacement
Bore x Stroke
Compression Ratio
Starting system
Ignition system
Lubrication system

Air cooled 4-stroke, forward incline, single, S.O.H.C.
2J2
499 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 type
Combustion chamber volume
(with BP7ES or N-7Y)
Head gasket thickness

Hemispherical

62.4 cc (3.81 cu. in.)
1.0 mm (.039 in)

Camshaft: 
Cam drive type
Camshaft bearing type (left)
Camshaft bearing type (right)
Cam chain type and No. of links

Drive chain (right side drive)
6005C3
6005C3 (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 pcs

47 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: Inner 
Free length: Outer
Spring rate: Inner

Spring 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:
Material
Bore size 

Taper limit 
Out Of round limit

required <allowable>
Aluminum alloy with cast iron sleeve
87.00 ~87.02 mm <87.1 mm> 
(3.4252 ~3.4260 in <3.429 in>)
<.05 mm> (<.0020 in>)
<.01 mm> (<.0004 in>)
Piston: 
Piston clearance 
Piston clearance measuring position 
(from piston skirt bottom) 
Piston pin bore size

Piston 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 ring 
Piston ring design: 2nd ring
Piston ring design: Oil ring
Ring end gap (installed): Top ring 

Ring 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 ring
Plain 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: 
Type 
Inside dia. x outside dia. x width 
Needle dia. x quality

Needle bearing
34 x 42 x 24 mm (1.34 x 1.65 x .94 in)
IKO 4 mm (.16 in) x 18 pcs
KOYO 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 type 
Clutch 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/quantity 

Clutch 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 type
Inner 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: 
Type 
Gear 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 speed
33/14 (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 system 
Shifting type 
Oil seal type: Change lever

Return type, left foot operation 
Guide bar type, cam drum system 
SDO-14-24-6
Kick starter: 
Type 
Oil seal type Kick axle

Ratchet type 
SD-25-35-7
Compression release: 
Type 
Lever free play 
Oil seal type

Manual, wire linked cam axle type 
2 mm (.079 in) 
SD-12-17-2.5-2NR
Air cleaner: 
Type/quantity

Dry foam rubber / l pc.
Carburetor: 
Type and manufacturer
I.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 MIKUNI 
2J200
#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 oil 
Quantity
 

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

Chassis specification (Top)

Frame: 
Frame design

Tubular steel semi double cradle
Steering system:
Caster 
Trail 
Steering head ballbearings: 
Upper race 
Lower race 
Lock to lock angle

27.5 deg (62.5 deg)
117 mm (4.6 in)

22 pcs. 3/16 in
19 pcs. 1/4 in
L.R. 41.5 deg

Front suspension: 
Type 
Front fork cushion travel

Front fork spring: 
Free length 
Set length 
Wire dia. x winding dia. 
Spring constant
 
 

Inner tube outside diameter 
Oil seal type 
Front fork oil: Quantity
Front fork oil: Type


Telescopic forks
150 mm (5.9 in) 

445 mm (17.52 in) 
417 mm (16.42 in)
3.6 x 24.3 mm (.14 x 0.96 in)
K1 = .4 kg/mm (0 ~ 100 mm) 
(22.4 lb/in (0 ~ 3.94 in)
K2 = .504 kg/mm (100 ~ 150 mm) 
(28.2 lb/in (3.94 ~ 5.91 in) 

35 mm (1.38 in)
SD-35-48-10.5
182 cc (6.15 oz) (6.41 IMP.oz) 
Yamaha fork oil 10 Wt. or equivalent

Rear suspension: 
Type 
Damper type 
Rear shock absorber travel 
Rear wheel travel 
Rear shock absorber spring: 
Free length 
Set length (soft position) 
Wire dia. x winding dia. 
Spring constant
 
 

Swing arm free play (limit) 
Pivotshaft: 
Outside dia. 
Bearing type and size
Dust seal type

required <allowable>
Swing arm 
Coil spring, oil damper 
80 mm (3.15 in)
110 mm (4.33 in)

216.5 mm (8.52 in) 
198 mm (7.80 in) 
7.5 x 61 mm (.30 x 2.40 in) 
K1 = 1.8 kg/mm (O ~ 50 mm) 
(100.8 lb/in (0 ~1.97 in)
K2 = 2.1 kg/mm (50 ~ 80 mm) 
(117.6 lb/in (1.97 ~ 3.15 in)
<1 mm (0.039 in)> 
16 mm (0.63 in)
L.R. Needle bearing (22-29-20) 
L.R. Thrust needle bearing (22-40.15-6) 
L.R. OSO-35-41.5-8

Fuel tank: 
Capacity 
Fuel grade

12 lit (3.2 US.Gal) (2.6 IMP.gal) 
Regular gasoline
Wheel: 
Type 
Tire size and pattern: Front 
Tire size and pattern: Rear 
Rim type: Front 
Rim type: Rear 
Rim runout (limit): Front/Rear 
Rim hopping (limit): Front/Rear 
Bearing type: 
Front wheel (Left) 
Front wheel (Right) 
Rear wheel (Left)
Rear wheel (Right) 
Oil seat type: 
Front wheel ( Left) 
Front wheel (Right) 
Meter gear 
Rear wheel (Left) 
Rear wheel (Right) 
Secondary drive chain:
Type 
Number of links 
Chain pitch 
Chain free play
required <allowable>
Casting wheel 
3.50-S19-4PR. lug type 
4.00-S18-4PR. lug type 
1.85-19 / Aluminum 
2.15-18 / Aluminum
<2 mm> (<.08 in>) 
<2 mm> (<.08 in>)

6303ZZ 
6303Z
6203RS 
6303ZZ

..................
SD-28-47-7-1 
SDD-45-56-6 
SD-25-40-8 
SD-28-47-7-1

DID 50 HDSS 
103L +Joint 
15.875 rnm (.6250 in) 
20 mm (0.79 in)

Brakes:
Type 
Disc size (Outside dia x thickness) 
Front 
Rear 
Disc wear/limit 
Disc pad thickness 
Pad wear limit (Minimum thickness)
Master cylinder inside dia. 
Caliper cylinder inside dia. 
Brake fluid type

Hydraulic disc type 

298 x 5 mm (11.73 x .02 in) 
267 x 5 mm (10.51 x .02 in) 
<4.5 mm> (<.18 in>)
11 mm (.43 in) 
<6 mm> (<.24 in>)
14.0 mm (.55 in) 
38.18 mm (1.50 in)
DOT #3 brake fluid

Electrical Specifications (Top)

Voltage  12V
Ignition system
C.D.I. 
Model/Manufacturer 
Pulser coil resistance 
High speed (White/Red-Black) 
Low speed (White/Green-Black) 
Charge coil resistance 
High speed (Red-Brown) 
Low speed (Brown-Black) 
Ignition timing:
Ignition advancer: 
Advance type 
Advance angle 
Advance starting engine speed 
Full advance engine speed 
Ignition coil: 
Model/manufacturer 
Spark gap 
Primary winding resistance 
Secondary winding resistance 
Spark plug: 
Type 
Spark plug gap 
C. D.I. unit: 
Model/Manufacturer
required <allowable>

032000-045 / NIPPON DENSO 

16 ohm +or- 30% at 20 deg C(68 deg F)
87 ohm +or-30% at 20 degC (68 deg F)

334 ohm +or- 30% at 20degC (68 deg F) 
329 ohm +or- 30% at 20 deg C (68 deg F)
BTDC 7 deg / 1100 r/min

Electrical 
26.5 deg
1,950 r/min 
6,000 r/min

029700-468 / NIPPON DENSO
<6 mm (.24 in) / 500 r/min>
.98 ohm +or- 20% at 20 deg C (68 deg F) 
12k ohm +or- 20% at 20 deg C (68 deg F)

BP-7ES (NGK)  N- 7Y (Champion) 
.7 ~ .8 mm (.028 ~ .031 in)

070000-035/NIPPON DENSO

Charging system: 
AC. magneto: 
Model/Manufacturer 
Rotor puller thread size
Output 
Stator coil resistance 
White-Yellow 
White-White 
032000-045 / NIPPON DENSO 
M27 x P 1.0 
14.5V-11A / 5000 r/min

.73 ohm +or- 30% at 20 deg C (68 deg F) 
.80 ohm +or- 30% at 20deg C (68 deg F) 

Rectifier/regulator: 
Model/Manufacturer 
(Rectifier) 
Type 
Capacity 
Withstand voltage 
(Regulator) 
Type 
Regulating voltage
Allowable amperage 
Battery: 
Model/Manufacturer
Capacity 
Charging rate 
Specific gravity

SH235 / SHINDENGEN

I.C. type. three phase full wave 
15A 
200V

I.C. type 
14.5 +or- .5V 
15A

12N7-3B / G.S.
12V, 7AH 
.7A x 10 hours 
1.280

Lighting system: 
Headlight type: 
Bulb wattage/Quantity: 
Headlight 
Taillight 
Brake light 
Flasher light 
Turn indicator light 
Meter light 
High beam indicator light 
Neutral indicator light 

Sealed beam 

12V, 50W/40W x 1
12V 8W (3CP) x 1 
12V 27W (32CP) x 1 
12V 27W (32CP) x 4 
12V 3.4W x 1 
12V 3.4W x 4 
12V 3.4W x 1 
12V 3.4W x 1

Horn:
Model/Manufacturer 
Winding resistance 
Amperage 
Flasher relay:
Type 
Model/Manufacturer 
Flasher frequency 
Capacity

CF-12 / NIKKO HORN 
1.24 ohm +or- 10% at 20 deg C (68 deg F)
2.5A

Condenser type 
FN257C / NIPPON DENSO 
85 +or- 10 cycle/min.
12V 27W x 2 + 3W

Fuse:
Rating

20A