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Greg Bender

Moto Guzzi Loop Frames - Differences between models

 
Antietam Classic Cycle - Excellent service spanning tune-ups to restorations
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Differences between V700, Ambassador, and Eldorado models

Like most things in life, these differences are not absolute. There was plenty of crossover as the models evolved and there are many exceptions. But, this can serve as a general guideline. Some of the photos and information came from Dave Otis' old website. I'm certain I missed something, so please contact me with any corrections, contributions, or additional photos: greg>at<thisoldtractor.com.

Special thanks to Mike Tiberio, Rob Prins, Newtin, Paul Linn, and Charlie Mullendore of Antietam Classic Cycle for providing additional difference information.

  V7 / V700 Ambassador Eldorado
Engine Case 3 shallower verticle ribs

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most had 3 deeper verticle ribs plus additional diagonal rib running rearward from cylinder base

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very late had horizontal webbing

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horizontal webbing

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Bore 80 mm 83 mm 83 mm
Stroke 70 mm 70 mm 73 mm
Displacement 703.717 cc 757.486 cc 844.05 cc
Piston rings 4, 3 above wrist pin, 1 below 4, all above wrist pin 3, all above wrist pin
Valves 38 mm intake and 34 mm exhaust 40 mm intake and 35 mm exhaust 40 mm intake and 35 mm exhaust
Valve springs Single Dual Dual
Compression Ratio 9:1 9:1 9.2:1
Maximum RPM 6000 6500 6500
Horsepower at maximum RPM (SAE) 50 60 64
Cylinder head exhaust port No boss for future exhaust studs

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Early models had no boss for future exhaust studs; later models had a boss for later exhaust studs

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Most had no boss for future exhaust studs; Some had a boss for later exhaust studs

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Cylinder head top stud One piece design with o-ring

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Early models had one piece design with o-ring; later models had two piece design with crush washer

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Two piece design with crush washer

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Valve covers early models had "Moto Guzzi" printed below raised area, no ridge on raised area, longer hex-head securing bolts

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later models had "Moto Guzzi" printed on raised area, no ridge on raised area, shorter allen-head securing bolts

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"Moto Guzzi" printed on raised area, no ridge on raised area, shorter allen-head securing bolts

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early models had "Moto Guzzi" printed on raised area, no ridge on raised area, shorter allen-head securing bolts

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later models had "Moto Guzzi" printed on raised area, ridge on raised area, shorter allen-head securing bolts

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Gas tank - capacity 4.5 gallon early models had 4.5 gallon

late models had 5.84 gallon
5.84 gallon
Gas tank - petcock position petcocks positioned forward

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early models had petcocks positioned forward

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late models had petcocks positioned rearward

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petcocks positioned rearward

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Gas tank - tunnel width

Thanks to Karl Kologiski for providing this difference information. Note: Wider tunnel tanks will fit on the earlier models. Narrow tunnel tanks will not fit on the later models.
narrow tunnel

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early models had narrow tunnel

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late models had wider tunnel

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wider tunnel

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Gas cap cap with lever, lever secured via special boss on tank

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early civilian models had cap with lever, lever secured via special boss on tank

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later civilian models had a cap with a lever, lever secure via ring and groove on neck

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police models had a screw-on cap, taller neck

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civilian models had a cap with a lever, lever secured via ring and groove on neck

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police models had a screw-on cap, taller neck

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Front brakes twin leading shoe
most had twin leading shoe
some very late models had four leading shoe (circa 1977)
most had twin leading shoe
some in 1973 had four leading shoe
late 1973 and 1974 had single disk
Rake 27° 27° 27°
Trail 56.94 mm 81.94 mm 81.94 mm
Triple tree offset 90 mm

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70 mm

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70 mm

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Transmission speeds 4 speed 4 speed 5 speed
Transmission gear ratios 1:2.230
1:1.333
1:0.954
1:0.750
1:2.230
1:1.333
1:0.954
1:0.750
1:2.000
1:1.388
1:1.047
1:0.869
1:0.750
Transmission case Smooth Smooth Ribbed
Transmission gear design Earlist all straight cut, middle first straight cut/second-fourth hellically cut, latest all hellically cut All hellically cut All hellically cut
Rear drive gearing 8/37 8/35 8/37
Rear drive case Polished starburst Polished starburst Deeper sump and not polished
Overall gear ratios (from engine through transmission to rear drive) 1:14.180
1:8.473
1:6.063
1:4.768
1:13.413
1:8.015
1:5.735
1:4.510
1:11.424
1:7.929
1:5.980
1:4.964
1:4.284
Carburetors Dell'Orto SS1 29mm; later models had an intake liner to increase air flow velocity Dell'Orto VHB 29mm Dell'Orto VHB 29mm
Carburetor body to intake manifold clamps Smooth polished aluminum band

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Early models had smooth polished aluminum band

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later models had steel bands perpendicular to the carb body

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Steel bands perpendicular to the carb body

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Shifter design Most had heel-toe, few had toe only Most had heel-toe, few had toe only Heel-toe
Shifter location Right side, had a different bend to clear the swingarm nut

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Left side Left side
Rear brake design Aluminum

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Chrome plated steel

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Chrome plated steel

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Rear brake plate Shaft at 12 o'clock, shoe pivot doubles as tie rod attachment point

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Early had shaft at 12 o'clock, shoe pivot doubles as tie rod attachment point

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later had shaft at 3 o'clock

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Shaft at 3 o'clock

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Rear brake location Left side Right side Right side
Shift pattern 1 up, 3 down 1 up, 3 down 1 up, 4 down
Headlight Deep shell Shallow shell Shallow shell
Tail light Had additional horizontal mount to the frame, round lens

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Early models had additional horizontal mount to the frame, round lens

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Later models lacked additional mount, round lens

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Early models lacked additional mount, round lens

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Later models had a rectangular lens

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Instrument panel Civilian models only had a speedometer See civilian and police variations here Early civilian models only had a speedometer; later civilian models had speedometer and tachometer See civilian and police variations here Civilian models had speedometer and tachometer See civilian and police variations here
Side covers Narrow, non louvered Early models had narrow, non louvered; later models had wider, louvered Wider, louvered
Tool boxes Knobs

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Early models had knobs; later models had locks

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Locks

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Coil Magneti Marelli Early models had Magneti Marelli; later models had Bosch Bosch
Coil mount Across the frame In line with frame In line with frame
Civilian frame Narrower backbone (later tank will fit on earlier frame, but not vice versa) Wider backbone Wider backbone
Police frame (in addition to civilian frame differences) Siren mount (mechanical sirens had different mounts than electrical - not sure of difference???), stronger gusset plate for seat, gusset plate drilled for rear crash bars, dimple in rear fender mount at the rearmost part of the frame Siren mount (mechanical sirens had different mounts than electrical - not sure of difference???), stronger gusset plate for seat, gusset plate drilled for rear crash bars, dimple in rear fender mount at the rearmost part of the frame Siren mount (mechanical sirens had different mounts than electrical - not sure of difference???), stronger gusset plate for seat, gusset plate drilled for rear crash bars, dimple in rear fender mount at the rearmost part of the frame
Generator Magneti Marelli Early models had Magneti Marelli, later models had Bosch Bosch
Generator covers Two individual metal plates (most painted, there is some debate as to whether or not some were chromed)

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Early models had two individual metal plates (most painted, there is some debate as to whether or not some were chromed)

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later models had a single black plastic cover

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Single black plastic cover

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Regulator Magneti Marelli Early models had Magneti Marelli; later models had Bosch Bosch
Starter Magneti Marelli Early models had Magneti Marelli; later models had Bosch Bosch
Center stand Short feet Early models had short feet; later models had long curved feet Long curved feet
Turn signals None None Front and rear
Fender reflectors None Early models had none; later models has reflectors with wide chrome trim; some very late models had reflectors with very narrow trim Early models had reflectors with wide chrome trim; later models had reflectors with very narrow trim
Fork covers / headlight ears Shorter Shorter Shorter for all drum brake models. Disc brake models are longer.
Swing arm Aluminum cap on the back end of the swing arm...just before the rear drive Boss that could be drilled for aluminum cap No boss.
Hand levers Smooth lever with a perch that angled toward the handlebar

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Early models used a smooth lever with a perch that angled toward the handlebar

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later models used a finger-grooved lever with a perch that was more square to the handlebar

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Finger-grooved lever with a perch that was more square to the handlebar

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models with 4 leading shoe front brakes used a finger-grooved lever with a special adpater to connect both front brake cables

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Shocks

Thanks to Newtin for providing this difference information. Note: the shocks must be completely disassembled to remove the chrome cover; the plastic cover can be distorted to clear the tabs at the bottom of the shock body.
Early models had a black plastic inner cover to hide the rod

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later models used a chrome steel cover to hide the rod

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Early models used a chrome steel cover to hide the rod

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later models had a black plastic inner cover to hide the rod

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All used a black plastic inner cover to hide the rod

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