Ural (Урал) - Dnepr (Днепр) Russian Motorcycle Part XIV: Plunger, Swing-Arm and Torsion Bar Evolution (
Ernie Franke [email protected] 09 / 2017 Swing-Arms and Torsion Bars for Heavy Russian Motorcycles with Sidecars • Heavy Russian Motorcycle Rear-Wheel Swing-Arm Suspension
–Historical Evolution of Rear-Wheel Suspension Trans-Literated Terms –Rear-Wheel Plunger Suspension • Cornet: Splined Hub • Journal: Shaft –Rear-Wheel Swing-Arm Suspension • Stroller, Pram: Sidecar • Rocker Arm: Between Sidecar Wheel Axle and Torsion Bar • One-Wheel Drive (1WD) • Swing-Arm – Rear-Drive Swing-Arm • Torsion Bar (Rod) • Sway Bar: Mounting Rod • Two-Wheel Drive (2WD) • Suspension Lever: Swing-Arm – Rear-Drive Swing-Arm • Swing Fork: Swing-Arm –Not Covered: Front-Wheel Suspension Torsion Bar • Sidecar Frames and Suspension Systems –Historical Evolution of Sidecar Suspension –Sidecar Rubber Bumper and Leaf-Spring Suspension –Sidecar Torsion Bar Suspension –Sidecar Swing-Arm Suspension • Recent Advances in Ural Suspension Systems –2006: Nylock Nuts Used to Secure Final Drive to Swing-Arm –2007: Bottom-Out Travel Limiter on Sidecar Swing-Arm –2008: Ball Bearings Replace Silent-Block Bushings in Both Front and Rear Swing-Arms
Heavy Russian motorcycle suspension started with the plunger (coiled spring) rear-wheel suspension on the M-72. This was replaced with the swing-arm (pendulum) and dual hydraulic shock absorbers on the K-750. Similarly the sidecar suspension was upgraded from the spring-leaf 2 to rubber isolators and a swing-arm approach in the M-72M. Not Covered: Front-Wheel Torsion Bar
3 History of Rear-Wheel and Sidecar Wheel Suspension • Rear-Wheel Suspension –Original M-72 Suspension • Plunger (Coiled-Spring) Rear-Wheel Suspension • Ural’s M-61 and M-62 Also Used Plunger Suspension System –Upgrades to Rear-Wheel Suspension • In 1958/9 Dnepr (KMZ) Introduced K-750, New Frame with Pendulum (Swing- Arm) Rear-Wheel Suspension and Coil-Spring Shock Absorbers • In 1965 Ural (IMZ) Introduced M-63 (Ural-2), M-66, M-67 and 8-103.10 which Transitioned from So-Called Candle-Frame of M-72/M-61/M-62 to New Bike Frame with Swing-Arm, Pendulum Rear-Wheel Suspension and Hydraulic Shock Absorbers • Sidecar-Wheel Suspension –Original M-72 Sidecar Suspension • Steel Leaf Springs • Until 1947, IMZ Did Not Let Sidecar Design Out of Gorky Plant • Later Ural and Dnepr Used Swing-Arm Suspension and Rubber Blocks, Replacing Leaf-Springs –In 1955 Ural (IMZ) Introduced M-72M with Sidecar-Wheel Torsion Bar Suspension • Retained Steel Leaf-Springs • Torsion Bar Mounted in Rear Cross-Member of Sidecar Frame • M-72M, M-61, M-62 Had Torsion Bar on Sidecar • Chinese-Built CJ750 (copy of M-72M) Has Torsion Bar Suspension – Has Both Leaf-Springs and Torsion Bar –In 1968/70 Ural (IMZ) Introduced M-63 (Ural-2), which Transitioned from Steel Leaf-Springs of M-72/M-61/M-62 to New Sidecar Frame with Swing-Arm, 4 Pendulum Sidecar-Wheel Suspension and Hydraulic Shock Absorbers Time-Line of Plungers, Swing-Arms and Torsion Bars Ural M-63, M-66, M-67 Ural M-61, M-62 Production Production, Plunger Rear-Wheel, Swing-Arm Rear-Wheel and Torsion Bar on Sidecar Hydraulic Shocks Dnepr Introduced Swing-Arm Rear-Wheel with K-750 Dnepr MB-650 M-72 Minor Redesigned and Issued as M-72M, Mother of All Ural Introduced Swing-Arm Torsion Bar Added to Sidecar Rear-Wheel with M-63 Russian Sidecars: M-72 Production Dnepr MB-750 Dnepr MB-750M
1940 1945 1950 1955 1960 1965 1970 1975 Taiga Sahara Ural 650cc Production, Wjuga Ural M-63, M-66, M-67 Swing-Arm Rear-Wheel and Ural “Patrol” Production, Hydraulic Shocks Pustinja Swing-Arm Rear-Wheel and (non-Diff 2WD) Hydraulic Shocks Raven Basic Dnepr Dnepr MB-650M MB-650 Ural “Sportsman” Ural “Patrol-T” Ural “Gear-Up” (non-Diff 2WD) Dnepr Dnepr Dnepr (non-Diff 2WD) MB-750M MT-12 MT-11, MT-16
1975 1980 1985 1990 1995 2000 2005 2010
Heavy Russian motorcycle production began with the plunger rear-wheel and spring-leaf sidecar suspension. Demands for operation on5 rough roads gave rise to swing-arms on both the rear-wheel and sidecar-wheel. Ural (Урал) / Dnepr (Днепр) Sidecar Drive Train and Rear Suspension Ural (Урал) Model Production Drive Train Rear-Wheel Rear-Wheel Sidecar Sidecar Suspension Swing-Arm Torsion Bar Swing-Arm M-72 1941-1950 Straight Final Drive (1WD) Plunger None (Plunger) None None M-72K 1952-1958 Straight Final Drive (1WD) Plunger None (Plunger) None None M-72M 1956-1960 Straight Final Drive (1WD) Plunger None (Plunger) 7220227 None M-61 1958-1961 Straight Final Drive (1WD) Plunger None (Plunger) 7220227 None M-62 (Ural-1) 1961-1965 Straight Final Drive (1WD) Plunger None (Plunger) 7220227 None M-63 (Ural-2) 1965-1971 Straight Final Drive (1WD) Swing-Arm 6309080-Б 7220227 None (None Later) (6320020 Later) M-66 (Ural-3) 1971-1973 Straight Final Drive (1WD) Swing-Arm 6309080-Б None 6320020 M-67 (IMZ-8.101) 1974-1976 Straight Final Drive (1WD) Swing-Arm 6309080-Б None 6320020 M-67.36 1976-1983 Straight Final Drive (1WD) Swing-Arm 6309080-Б None 6320020 Sportsman IMZ 8.107 1995-1998 2WD with non-Locking Differential Swing-Arm IMZ-8.107-09081 None IMZ-8.103-20019-20 8.103 Series “650” 1WD 1984-2002 Straight Final Drive (1WD) Swing-Arm IMZ-8.103-09081 None IMZ-8.103-20019-20 8.103 Series “650” 2WD 1999-2002 1WD with Engagable 2WD (No Diff) Swing-Arm IMZ-8.107-09081 None IMZ-8.107-20019-6Б “750”Series 1WD 2003-Present Straight Final Drive (1WD) Swing-Arm IMZ-8.103-09081 None IMZ-8.1037-20019-01 “750”Series 2WD 2003-Present 1WD with Engagable 2WD (No Diff) Swing-Arm IMZ-8.107-09081 None IMZ-8.107-20019-01 Dnepr (Днепр) Model Production Drive Chain Rear Rear Sidecar Sidecar Suspension Swing-Arm Torsion Bar Swing-Arm M-72 1951-1956 Straight Final Drive (1WD) Plunger None (Plunger) None None M-72N (H) 1956-1960 Straight Final Drive (1WD) Plunger None (Plunger) None None K-750 1959-1963 Straight Final Drive (1WD) Swing-Arm 5309200 7220227 650202-Б K-750M 1963-1977 Straight Final Drive (1WD) Swing-Arm 5309200 7220227 650202-Б MT-12 (Dnepr-12) 1974-1982 2WD with Non-Locking Differential Swing-Arm ВП09800 None ВП50510 MB-750 1964-1973 2WD with Locking (Engagable) Diff Swing-Arm ВП09800 None ВП50510 MB-750M 1973-1977 2WD with Locking (Engagable) Diff Swing-Arm ВП09800 None ВП50510 K-650/MT-8 1967-1971 Straight Final Drive (1WD) Swing-Arm 65009200 None 650202-8Б K-650/MT-9 1971-1976 Straight Final Drive (1WD) Swing-Arm 65009200 None 650202-8Б MB-650 1968-1984 2WD with Locking Differential Swing-Arm ВП09800 None ВП50510 MB-650M 1985-1991 2WD with Non-Locking Differential Swing-Arm ВП09800 None ВП50510 MT-10 1973-1976 Straight Final Drive (1WD) Swing-Arm 65009200 None 650202-8Б MT-10.36 1976-1984 Straight Final Drive (1WD) Swing-Arm 65009200 None 6502026 -8Б MT-11 (Dnepr-11) 1985-1995 Straight Final Drive (1WD) Swing-Arm 65009200 None КМЗ-8.15720200 MT-16 (Dnepr-16) 1986-1995 2WD with Non-Locking Differential Swing-Arm ВП09800 None ВП50510 Early Rear-Wheel Swing-Arm Suspension • Every Ural and Dnepr Has Swing-Arm Suspension with Spring-Hydraulic Shock Absorbers –Except for M-72, M-61 and M-62, with Rear-Wheel Plunger (Coil-Spring) Suspension –In 1959 the Dnepr K-750 Appeared, Losing the Old Plunger Frame Design in Favor of a Swing-Arm Design, Giving More Suspension Travel and a Better Ride Over Rough Terrain Motorcycle (Factory) Suspension Type Production M-72 (IMZ, KMZ) Plunger 1941-1956 M-72K (IMZ) Plunger 1954-1960 M-72 Rear Suspension M-72M (IMZ) Plunger 1956-1960 M-72N (KMZ) Plunger 1956-1959 K-750 (KMZ) Swing-Arm 1959-1963 K-750M (KMZ) Swing-Arm 1963-1977 Ural M-61 (IMZ) Plunger 1958-1961 Ural M-62 (IMZ) Plunger 1961-1965 Ural M-63 (IMZ) Swing-Arm 1965-1971
M-72 pioneered the plunger (coiled-spring) suspension, which was replaced7 in the K-750. Ural’s M-61 and M-62 also used the plunger suspension system. 1954 M-72 Rear-Wheel Suspension
1. Rear Fork Base Cap 2. Spring 3. Spring Housing Motorcycle 4. Right Suspension Support Frame 5. Guide Sleeve Motorcycle 6. Bar Frame 7. Buffer 8. Lock Screw 9. Absorber 10.Stuffing Box Rear-Drive
Rear-Drive Motorcycle Frame
1. End Caps of Rear Fork Motorcycle 2. Spring Frame 3. Spring Housing 4. Right Suspension Support 5. Guide Sleeve Coiled-Spring Isolation between 6. Bar Motorcycle Frame and Rear-Drive 7. Buffer
8 The M-72 had a plunger (coiled-spring) rear-wheel suspension. Evolution from Plunger (M-72) to Swing-Arm (K-750) Rear-Wheel Suspension
M-72
Plunger (Coiled-Spring) Suspension
K-750
Swing-Arm Suspension with Spring/Hydraulic Shocks
9 M-72 Sidecar
Frame Loop over Fender
The M-72 “Tub” Is Suspended on Leaf-Springs
Nearly all sidecars from the war vintage M-72 production have a rigid wheel suspension for the sidecar, as seen by a frame loop going over the top of the sidecar fender. This was also used on Chang Jiangs to about 101970, when they added a torsion bar suspension. Torsion Bar Suspension • Torsion Bar Suspension, a.k.a. Torsion Spring Suspension, Uses a Torsion Bar as Its Main Weight-Bearing Spring • Torsion Bar, the Elastic Absorber, Is a Metal Rod with Circular Splined Ends –One End Is Firmly Attached to the Sidecar Chassis –Opposite End Terminates in a Lever, Mounted Perpendicular to the Torsion Bar, that Is Attached to a Suspension Arm, Spindle or Axle (Rocker Arm) • Vertical Motion of Sidecar Wheel Causes the Torsion Bar to Twist around Its Axis and Is Resisted by the Bar's Torsion Resistance, thus Achieving Elastic Coupling between the Sidecar Wheel and the Sidecar Body • Torsion Feature Is that Rotation in Only One Direction - Towards Twisting • Effective Spring Rate of the Torsion Bar Determined by Its Length, Shape, Material, Cross-Section and Manufacturing Process • Another Feature: Torsion Bar Can Be Used to Adjust the Height of the Sidecar
Torsion Bar with Torsion Bar with No Load Applied Wheel-Axle Load Applied (Static) Sidecar Frame Sidecar Frame
Sidecar Wheel’s Sidecar Wheel’s Rocker Arm Rocker Arm
11 Sidecar Wheel Axle Sidecar Wheel Axle Sidecar Frames, Leaf-Springs and Torsion Bars • Sidecar Frame Has Rigid, Reinforced, Double-Frame, Welded Tubular Construction • Rectangular Frame Connected to Ball Clamps (3,23) and Two Adjustable Tie-Rods (9, 37) • Brackets Welded at Rear of Sidecar Frame for Quarter-Elliptic Steel Leaf-Springs • Sideacar Frame (11) Connected to Torsion Bar Suspension 1. Motorcycle Frame 3. Front Collet Chuck 4. Bolt Collet Fitting 9. Rear Tie-Rod Mounting Bar 11. Sidecar Frame 12. Spring 13. Spring Ladder 14. Lever Axle 15. Sidecar Wheel Axle 16. Wheel Protective Cap 22. Shoe Springs 23. Rear Collet Chuck 24. Idler Arm Rear Suspension 36. Adjusting Fork Rod 37. Front Tie-Rod Mounting Bar
Torsion Bar Suspension of Sidecar-Wheel
Ural M-63
Sidecar Wheel Axle 12 M-72M Torsion Bar Suspension on Sidecar-Wheel Sidecar Torsion Bar Cornet Part #: 7220209
Splined Collet Firmly Anchored in Sidecar Frame Cross-Member
M-72 Sidecar Torsion Bar and Cornets
M-72 Sidecar Torsion Bar Cornet
M-72 Sidecar-Wheel Rocker-Arm
Other End of Torsion Bar Anchored in Splined Collet of Sidecar-Wheel Rocker-Arm Sidecar-Wheel Axle
Ural (IMZ) introduced the torsion bar on the sidecar with the M-72M. It continued with the torsion bar from 1955 to 1965 with the M-61 and M13-62, abandoning it with the M-63 with swing-arm sidecar suspension. K-750, M-61 and М-62 Sidecar-Wheel Torsion Bar (figure on next slide) • Torsion Bar Suspension Consists of Torsion Shaft (Bar, Rod) Made of Special Spring Steel and Mounted Across the Sidecar Frame • Torsion Wheel Suspension Mounted in Rear Cross Tube (4) of Sidecar Frame • One End of Torsion Bar (5) Rigidly Fixed to Sidecar Frame • Other End of Torsion Bar Fastened to Axis of Sidecar-Wheel Arm (Rocker-Arm) • Torsion Bar (5) Is Splined on Each End for Insertion into Collet (Inner Sleeve) (15) • Inner Sleeve (Collet) Is Splined and Firmly Attached to Sidecar Frame Tubing • Axle of Rocker-Arm (3) Is Hollow with Internal Splines to Accept Torsion Bar • Sidecar Wheel Moves Up-and-Down Relative to the Frame, Twisting Torsion Bar • Vibrations Are Absorbed by Elasticity of Torsion Bar • Movement of Lever Is Limited in the Vertical Plane by Bracket (9) Welded to the Right Longitudinal Tube of the Sidecar Frame • Maximum Upward Blows on the Lever Arm Are Absorbed by Rubber Buffer (10), Attached to Limiter-Stop Bracket (9)
14 K-750, M-61 and М-62 Sidecar-Wheel Torsion Bar (cont.)
Sidecar Torsion Bar and Cornets
Sidecar-Wheel Rocker-Arm
1. Torsion Cap 9. Limiter Stop 2. Seal Clip 3. Axle of Lever Hub Limiter Range 4. Rear Tubing of Sidecar Frame 5. Torsion Bar (Rod) 6. Locking Screws 7. Claw-Clamp to Motorcyce Frame 8. Left Tube of Sidecar Frame Sidecar-Wheel Rocker-Arm 9. Travel Stop Arm 10. Rubber Buffer 11. Sidecar Wheel Axle 12. Axle Lever (Rocker-Arm) 13. Seal 14. Ring Seal 15 15. Collet (Splined Inner Sleeve) Rear and Sidecar Wheel Suspension (2000 650cc Shop Manual) 1. Motorcycle Frame 2, 7. Adjusting Rods (front and rear) 3, 6. Collet Lower Frame Sidecar Mounting Points 4. Sidecar Frame 5. crank
1. Rear Suspension Swing-Arm 10. Collet Clamp 20. Sidecar Wheel Lever 2. Rear Mud Flap 11. Collet Clamp Screw 21. Brake Tie Rod 3. Rear Grab Bar 12. Motorcycle Stand 22. Brake Drum cover 4. Spring-Loaded Hydraulic Shock Absorber 13. Brake Pedal 23. Sidecar Wheel Axle 5. Seat (Saddle or Tractor) 14. Sidecar Wheel Brake Lever 24. Protective Hood 6. Strap 15. Sidecar Frame Legs 25. Tie Rod Nut 7. Motorcycle Frame 16. Sidecar Wheel Brake Rod 26. Sidecar Fender 8. Sidecar Adjusting Strut 17. Rear Collet Clamp Bracket 27. Rubber Body Suspension 9. Sidecar Frame Legs 18. Rear Bracket Fastening Bolt 28. Parking Brake 19. Lever Pins (Long Bolts) The rear-wheel is suspended on a trailing swing-arm, pivoting on rubber (silent-block) bushings located by removable pins in the frame and supported by dual hydraulic shocks/springs. The final drive attaches to the right-hand side of the swing-arm. The sidecar-wheel is carried on a forked, trailing-link swing-arm, supported by a single16 hydraulic/shock/spring, pivoting in silent block bushings around long bolts (“lever pins”). M-61 / K-750 Sidecar Frame (bike78.narod.ru) • Sidecar Frame (Chassis) (figure on next slide) –Welded Tubular Frame • M-61 / K-750 Sidecar Frame Fastened to Motorcycle Frame at Four Points –Two Ball Chucks (collets) at Bottom (to motorcycle frame) –Two Bolted Connections at Top (front under tank and rear behind the saddle) –Ball Joints on Motorcycle and Collets on Arms of Sidecar Frame –Petal-Shaped Bowl Draws Ball into Socket Using Bolt –Tie-Rods Adjustable in Length, Allow Alignment Relative to Motorcycle • Sidecar Wheel Axle Resiliently Isolated from Frame by Torsion Bar / Rocker-Arm –Swing-Arm Lever Pivots on Sleeve Bearing with Rubber-Metal Bushings (Silent-Blocks) –Torsion Bar, Spring Shock Absorbers (like shock absorbers installed in rear- wheel suspension), and Rubber Mounts Used for Isolation –Torsion Bar Implementation • Sidecar Wheel Axle (1) Mounted on Rocker-Arm (2) • Torsion Bar (3) Twists as Rocker-Arm Moves Up-and-Down • Ural M-61 Sidecar Dual Leaf-Springs • Dnepr’s K-750 Sidecar Has Rubber Isolators Instead of Leaf-Springs
Sidecar Attachment Clamp Joint 1. Clamp (Collet or Claw) 2. Nut 3. Bolt 17 Sidecar Mounting Bar (Tie-Rod) K-750 / M-61 Sidecar Torsion Bar Suspension and Frame (cont.)
M-61 Sidecar Frame 1. Connection Ball (Clam-Shell) 2. Connecting Rods 3. Sidecar Frame 1. Sidecar Wheel Axle 4. Sidecar Fender 2. Lever Axle (Rocker-Arm) 5. Sidecar Wheel Axle 3. Torsion Bar (Rod) 4. Locking Screws to Adjust Wheel Axle 5. Splined Hub (Cornet)
The rocker arm for the sidecar axle was isolated using a torsion bar mounted in the rear cross-member of the sidecar tubular frame. Ural’s M-61 sidecar still retained the dual leaf-springs for suspension,18 whereas Dnepr’s K-750 used rubber bumpers plus the torsion bar. Ural М-63 Frame and Sidecar (Рама и коляска) •Frame Is Main Weight-Bearing Element –All Components and Assemblies Are Attached –Double, Tubular, Welded, Closed Type of Frame 1 - motorcycle frame 20 - turn lamp 2 - front motor pin 21 - carrier body 3 - front collet chuck attachment 4 - bolt collet 22 - shoe springs 5 - motorcycle stand 23 - back collet chuck 6 - foot brake pedal 24 - idler arm rear 7 - step right driver suspension 8 - supports clipboard 25 - shock absorber 9 – sidecar rod mounting Torsion Baron 26 - license plate bracket frame Sidecar Suspension 27 - yoke back plate 10 - passenger footrest 28 - passenger seat 11 - sidecar frame 29 - passenger handle 12 - spring 30 - back plate 13 - spring clamp 31 - driver's seat 14 - wheel axle lever 32 - gas tank bracket 15 - sidecar wheel axle 33 - left footrest Driver 16 - protective cap kit 34 - bracket motor 17 - protective disc brake 35 - rear motor hairpin drum 36 - adjusting fork rod 18 – buffer 37 - sidecar rod mounting 19 – sidecar fender frame
Sidecar frame is connected to the motorcycle frame thru collets. 3 and 23 and two rods (9 and 37). At the rear of the frame are welded brackets for the quarter-elliptic leaf springs. The sidecar wheel frame (11) is connected to the torsion bar suspension. To protect against contamination of 19 brake drums, the inner cavity is closed (17). Ural М-63 Sidecar (коляска) Torsion Bar
1 - plug torsion 2 - gland (seal) 3 - hub axis of the lever 4 - rear frame tube 5 - torsion bar 6 - tightening bolts 7 - rear bracket collet connection 8 - left tube stroller frame 9 - stroke limiter control arm 10 - rubber buffer 11 - wheel axle 12 - lever of the wheel axle 13 - seal 14 – gland (seal) ring 15 - lever pivot pin
The torsion arm is mounted in the rear transverse frame tube (4). The torsion bar (5) has ends of small triangular splines for connecting the inner tube and the axis of the coupling arm (15). The inner sleeve has a slot-pipe hole and is welded to the frame tube. The axis arm (3) is hollow with internal splines. Outer surfaces polished lever pivot pin mounted in the hub axis (3). At the outer end of the shaft lever attached a woodruff key and bolted wheel axle lever (12). The hub axis of the arm is inserted into the back of the frame cross (transverse) tube and the flange is attached to the frame of the sidecar. Moving the lever wheel axis in the vertical plane is limited by the bracket (9) welded to the right of the longitudinal frame tube. Sharp fluctuations are absorbed by the rubber buffer (10) attached to the bracket. 20 Mounting Rods or Sway Bars and Claw Fittings MB-750 MT-16, MB-650M and MB-650M1 MT-12 and K-650
Sidecar Attachment Collet or “Clamshell” to Motorcycle 1. Front Tie Rod 2. Middle Tie Rod 3. Rear Clamp 4. Front Clamp
Sidecar Claw Coupling Sidecar Attachment Clamp Joint Sidecar Mounting Bar 1. Clamp (Collet or Claw) 21 2. Nut 3. Bolt Dnepr 2WD Sidecar Transverse Drive Shaft
Transverse Propshaft
Transverse Propshaft Sidecar Gear Reducer
22 With the tub removed, the sidecar drive shaft and gear reducer is clearly seen. Ural M-63, M-66, M-67 Swing-Arm Frame
4 Holes for Mounting Swing-Arm Directly to 1WD Rear Drive Casing 1.Silent Block Pendulum Fork 2.Spacer 3.Plug 4.Bolt lower tip 5.Swingarm Rear Suspension Fork 6, 7. Threaded Bushing Assembly 8. Pendulum Fork Bolt 9. Washer 10, 11, 12, 13. Reinforcing Plate 14. Rubber Bushing 15. Frame 16. Spring Shock Absorber
Because Ural’s M-63 / M-66 / M-67 do not offer 2WD, 23 the swing-arm is not C-shaped on the open end. Ural M-63 (Ural-2) with Rear-Wheel, Swing-Arm Suspension
The M-63 was the first Ural to use a rear-wheel, swing-arm suspension.24 Unlike Dnepr (KMZ) bikes, the swing-arm is on the outside of the frame. M-63 Suspension: Plunger, Torsion Bar or Swing-Arm?
1963 (Start of M-63 Production Line)
Plunger (from M-62 Parts) Torsion Bar (No Swing-Arm)
1972 (End of M-63 Production Line)
Swing-Arm (from M-63 Parts) Swing-Arm (No Torsion Bar )
As strange as it may seem, Ural changed motorcycle and sidecar suspension25 in mid-stream. I’m sure that never happened before! Pining Down the Year of Change
1968 M-63 Swing-Arm Swing-Arm (No Torsion Bar )
Swing-Arm (No Torsion Bar ) 1970 M-63
Swing-Arm
It appears that by 1968/70, Ural had instituted changing replacing the plunger with the swing-arm on the motorcycle and 26 replacing the torsion bar with a swing-arm on the sidecar. 1WD versus 2WD Suspension of Rear Drive • Swing-Arms Differ on the Drive Side –1WD Swing-Arm Has a Simple Plate Which Bolts to Four Studs around the Axle Hole of the Rear Drive Casing –2WD Swing-Arm Has a C-Shaped Fork Which Attaches to the Circumference Bolts on the Rear Drive Casing
2WD: C-Shaped Fork of Rear Drive Swing-Arm
Gearboxes are also distinguished by the appearance and method of fastening27 to an arm rear suspension. MT-16 Rear Drive and Sidecar Wheel Gear Reducer (Ken Ulrich U-2 Cycles)
Swing-Arm Suspension
Sidecar Pendulum Gear Reducer Differential rear Drive,Transverse Axle and Sidecar Gear Reducer and Sidecar Wheel Brake
Sidecar Pendulum Gear Reducer
2WD Swing-Arm Suspension
28 IMZ-8.108-40 Tourist and IMZ-8.107 Sportsman
1. Rear Suspension Swing-Arm 2. Rear Mud Guard 3. Rear Grab Bar 4. Spring-Loaded Hydraulic Shock Absorber 5. Seat (Tractor or Saddle) 6. Strap 7. Motorcycle Frame 8. Sidecar Adjusting Strut 9. Sidecar Frame Leg 10. Collet Clamp 11. Collet Clamp Screw 12. Motorcycle Stand 13. Brake Pedal 14. Sidecar Wheel Brake 15. Sidecar Frame Leg 16. Sidecar Wheel Brake Rod 17. Rear Collet Clamp Bracket 18. Rear Bracket Fastening Bolt 19. Lever Pins 20. Sidecar Wheel Lever 21. Brake Tie Rod 22. Brake Drum Cover 23. Sidecar Wheel Axle 24. Protective Hood 25. Tie Rod Nut 26. Sidecar Fender 27. Rubber Member of Body Suspension 28. Parking Brake
The sidecar frame is coupled to the motorcycle frame through 29 collet clamps (10), rear collet clamp brackets (17) and two frame legs (9, 13). Examining the Chang Jiang (CJ750) Motorcycle • Chang Jiang (CJ750) Is Daughter of M-72 –CJ750 Motorcycle and Sidecar Based on the 1956 Soviet IMZ (Irbitski Mototsikletniy Zavod) M-72, Which Was Derived from the 1938 German R71 –In the USSR, Now That the Side-Valve (SV) Model Had Become Obsolete, Manufacture of the Old M72 Offered It to Their Chinese Neighbors –In 1957, the M-72 IMZ Production Line Transferred to People’s Republic of China (PRC) State-Owned, Gan Jiang Machinery Factory, and Renamed the Chang Jiang 750 –Early Motorcycles Built Using Various Imported Russian Parts, and Even Some Complete Russian-Made M-72s Relabeled as CJ750 –Side-Valve CJ750 Still In Production with Few Changes from Original Design • Examining the Chang Jiang (CJ750) Helps to Understand the Modern M-72 –Often the CJ750Drawings Are Copies of 1955 M-72 Drawings • Chang Jiang 750 M1, CJ750 M1S (Super) and CJ750 M1M All Have Torsion Bar Suspension, Rocker Arm for the Sidecar Suspension and Plunger Rear Wheel Suspension
CJ750 Sidecar Torsion Rod
CJ750 Sidecar-Wheel Shaft Rocker Arm 30 CJ750 Sidecar Springs Chang Jiang (CJ750) Side-Wheel Axle Assembly (Sidecar-Wheel Shaft Rocker Arm)
1. Split Pin (Cotter Pin) 2. Castle Nut 3. Washer 4. Drum Cap 5. Rocker Arm 6. Torsion Rod 7. Side-Wheel Shaft 8. Screw 9. Washer 10. Rubber Buffer 11. Bolt 12. Plug Sealing Washer 13. Locking Spring Ring Felt Ring 14. Nut 15. Tab Washer 16. Lip 17. Sealing Gasket 18. Felt Ring 19. Sealing Washer Packing 20. Bushing 21. Fly Sleeve 22. Fly 23. Key 24. Bolt 25. Washer 26. Washer 27. Split Pin (Cotter Pin)
The CJ750 diagram clearly shows the torsion bar 31 in the 1951 version of the Russian M-72. CJ750 Sidecar Frame Assembly 1. Sidecar Frame 2. Side-Wheel Mudguard 3. Mudguard Middle Support 4. Nut 5. Spring Washer 6. Bolt 7. Anti-Shock Screw Shaft 8. Washer 9. Support 10. Fillet 11. Bush 12. Leaf Spring U-Bolts 13. Spacer 14. Spring Steel Plate 15. Anti-shock Shaft Bracket 16. Spacer 17. Rivet 18. Spring Washer 19. Nut 20. Bolt 21. Jaw Pipe Joint 22. Protective Plate 23. Nut 24. Spring Washer 25. Nut 26. Adjusting Screw 27. Split Pin 28. Bolt 29. Nut 30. Spring Washer 31. Rear Mounting Rod 32. Nut 33. Rear Mounting Screw 34. Lug 35. Spring Washer 36. Nut 37. Nut 38. Spring Washer 39. Joint for Mounting Rod 40. Front Mounting Rod 41. Anti-Shock Rubber 42. Front Mounting Screw 43. Bolt 44. Washer 45. Screw 46. Spring washer 47. Washer 48. Nut 32 The CJ750 sidecar frame assembly mimics the 1951 version of the Russian M-72. CJ750
Because it was a Chinese, we can see some 33 of the old features of the M-72, including the sidecar. 1. Steering Bearing CJ750 Frame Assembly 2. Motorcycle Frame 3. Nut 4. Washer Attachment Points 5. Bolt for Plungers 6. Fixing Bolt 7. Brake Rubber 8. Kick-Stand 9. Cotter Pin 10. Kick-Stand Support Shaft 11. Kick-Stand Washer 12. Kick-Stand Spring 13. Foot Pedal Rod 14. Foot Pedal Rod 15. Foot Pedal Rubber Sleeve 16. Battery Short Strap 17. Battery Long Strap 18. Battery Tightening Nut 19. Engine Body Link Support 20. Angle Iron 21. Clip 22. Rubber Spacer 23. Spacer 24. Nut 25. Screw 26. Spacer 27. Bolt 28. Washer 29. Nut 30. Nut 31. Washer 32. Bolt 8-12 Kick-Stand 16-18 Battery Holder
13-15 Foot Pedal
The CJ750 sidecar frame assembly clearly shows the attachment points34 for the plunger suspension system. M-72 Modeling (www.smcars.net)
7-Leaf Spring Bracket for Sidecar Tub
Original M-72 with Bar over Sidecar-Wheel Fender Plunger (Coil-Spring) Rear-Wheel Suspension
Dual Spring-Leaf Suspension of the Tub
35 Modeling of the old M-72 sidecar clearly shows the rigid frame over the fender.