My Mk3 was built in 1977, but wasn't registered until 1984 (on an 'A' plate..) I bought her in 1989 when it was absolutely factory standard, had been registered for only 5 years and had only 3200 miles on the clock (yet it had already had 3 former owners?..) The only badly assembled thing I ever found was that the centre head bolt was just dropped into it's hole, this revealed itself by blowing the original composite head gasket ! - I fitted a solid copper head gasket and it's been fine ever since.. While the bolt was 'on the loose' it's rattling had worn away the first three or four threads in the barrel, but luckily it still had enough to tighten down securely.. Apart from peashooters it's still standard and it's been a great bike, I absolutely love it !
I've had my 1977 registered Mk3 since 1982, when I bought it second hand, as it had apparently been traded in for a Laverda Jota. It was crashed by the first owner 6 months after he bought it and was rebuilt. I have got its mileage up to 100,000. The bike was originally a silver Interstate and as Ashley suggested was quite heavy. I converted it to Roadster specification, put peashooter pipes on it and an unbalanced exhaust, and this lightened it a little. I converted it to Boyer years ago and it is still running it's second black box. I had a Prestolite dealer convert the starter to 4 brushes and put in a 750 battery tray so that a bigger battery could be fitted and together with a different solenoid the starter was quite reliable. It has a single Amal carb conversion, which makes the throttle much lighter but knocks the acceleration down. The bike itself is reliable, but I have found that riding it for over 40 years that modern cars have got a lot faster and my poor old Mk 3 is still quite heavy compared to the 750 Commando, and so gets passed by quite easily. I would recommend a Mk3, but a very light 750 will have you grinning more.
Thank you for outlining the "pre-production" vehicle process; it is little known and greatly misunderstood among Commando enthusiasts. Most years during Commando production (and it happened pretty much every year) the process was repeated. There were three stages of these "pre-prod" motorcycles. The first were some special ones, built with production or at least production-looking components for special purposes, such as photography for sales and brochure purposes, dealer launch shows or meetings, public shows, influential magazine road tests timed to hit sales at the time the first motorcycles arrived at dealers, etc. Sometimes, these motorcycles didn't have parts inside the engine or gearbox but they were as complete as they needed to be. Most of these motorcycles were so far from final production spec that they couldn't be sold to the public, at least not without significant rebuilding or refitting. The second stage was for production fit and process. These motorcycles were put down the production line using fully-production spec components to validate all aspects of the assembly process. All the time that it took to assure that things fit together properly, were correctly sequenced on production (i.e. you can't have a process that calls for assembly of wheels to a motorcycle on the line before the wheels are spoked up, trued, and tyres fitted, as a silly-simple example), and all the non-vehicle items in the production process are present and correctly outfitted (tools like torque spanners, alignment jigs, bins for newly-introduced parts properly sized and located in the stillages at the correct assembly stages, etc.). As I mentioned, these were slow processes to assess that everything was right to produce the motorcycles and time was taken for measurements, installation of new tools or fixtures, and worker training. Then the results of the analyses done were returned to design engineering and production engineering staff for final validation and technical review. In theory, these motorcycles were fully to the specification of the motorcycles that were planned when full series production was to begin. The final "preprod" stage was a batch of motorcycles that were built on the production line at full production schedule speed. These builds were done by the assembly line workers using the established production processes and they were timed to assure that the most efficient procedures were used to build the production motorcycles to the lowest cost and quickest time involved in the process. While there was some involvement of production engineering and production planning personnel, they were mostly involved in overseeing and measuring each process rather than being actually a part of the processes. The finished motorcycles were mostly held for dispatch to distributors until series production had begun although there were cases where addition motorcycles were built at this stage to meet market demand. In the case of the introduction of the new models for production meant for January, 1972 -- the introduction of the Combat engine, the front disc brake, and the Interstate models -- there were a number of full-production pre-prod motorcycles built from October through December, 1971; some of these motorcycles were shipped to Australia, New Zealand, South Africa and other Southern Hemisphere markets so that they could be put into dealers' showrooms with timing to match their "selling season". Others were used to obtain the new processes instituted by mostly European governments for "Type Approval" of new models and for dealer stock for these markets, and more motorcycles than previously had been built for allocation to the N. American distributors (Berliner in the eastern US, Norton Villiers Corporation in the west, and Canadian distributors) so that the distribution "pipelines" in these markets could be filled for a more-than-adequate number of motorcycles to supply the expected sales of these new models. A brief look at production dispatch records and serial number batches indicates that at least 1200 motorcycles of the "1972 models" were built and mostly put into distribution prior to the actual start of production of the 1972 Commandos. If you include some early builds with standard engines (it was originally planned for the Combat engine to be an "option" at additional cost but market demand meant that this never really happened; also, the '72 model Hi-Rider Commandos were specified to have standard engines), it could be that the total number of these pre-prod '72 Commando could have reached 1600 - 2000 finished motorcycles -- prior to the "official" start of production of these models. This is very different to the earlier years when the number of pre-prod motorcycles probably did not reach more than 25 - 40 total of the three types, and it was not repeated in '73 due to a number of unsold Commandos in stock at the end of 1972 following the "Combat" engine failure and the fact that the 850 was not available for the beginning of production until the spring of 1973. A deep financial depression worldwide following the first major "Oil Crisis" also meant that production plans for 1974 did not call for a significant number of pre-prods. The number of a significant pre-prod motorcycles in 850 Mk3 production in late 1974 prior to official start of 850 production again mirrored that experience from 1972 and produced the situation as described by Ashley in this video.
My Mk3 was built in 1977, but wasn't registered until 1984 (on an 'A' plate..) I bought her in 1989 when it was absolutely factory standard, had been registered for only 5 years and had only 3200 miles on the clock (yet it had already had 3 former owners?..) The only badly assembled thing I ever found was that the centre head bolt was just dropped into it's hole, this revealed itself by blowing the original composite head gasket ! - I fitted a solid copper head gasket and it's been fine ever since.. While the bolt was 'on the loose' it's rattling had worn away the first three or four threads in the barrel, but luckily it still had enough to tighten down securely.. Apart from peashooters it's still standard and it's been a great bike, I absolutely love it !
I've had my 1977 registered Mk3 since 1982, when I bought it second hand, as it had apparently been traded in for a Laverda Jota. It was crashed by the first owner 6 months after he bought it and was rebuilt. I have got its mileage up to 100,000. The bike was originally a silver Interstate and as Ashley suggested was quite heavy. I converted it to Roadster specification, put peashooter pipes on it and an unbalanced exhaust, and this lightened it a little. I converted it to Boyer years ago and it is still running it's second black box. I had a Prestolite dealer convert the starter to 4 brushes and put in a 750 battery tray so that a bigger battery could be fitted and together with a different solenoid the starter was quite reliable. It has a single Amal carb conversion, which makes the throttle much lighter but knocks the acceleration down. The bike itself is reliable, but I have found that riding it for over 40 years that modern cars have got a lot faster and my poor old Mk 3 is still quite heavy compared to the 750 Commando, and so gets passed by quite easily. I would recommend a Mk3, but a very light 750 will have you grinning more.
Thank you for outlining the "pre-production" vehicle process; it is little known and greatly misunderstood among Commando enthusiasts. Most years during Commando production (and it happened pretty much every year) the process was repeated.
There were three stages of these "pre-prod" motorcycles. The first were some special ones, built with production or at least production-looking components for special purposes, such as photography for sales and brochure purposes, dealer launch shows or meetings, public shows, influential magazine road tests timed to hit sales at the time the first motorcycles arrived at dealers, etc. Sometimes, these motorcycles didn't have parts inside the engine or gearbox but they were as complete as they needed to be. Most of these motorcycles were so far from final production spec that they couldn't be sold to the public, at least not without significant rebuilding or refitting.
The second stage was for production fit and process. These motorcycles were put down the production line using fully-production spec components to validate all aspects of the assembly process. All the time that it took to assure that things fit together properly, were correctly sequenced on production (i.e. you can't have a process that calls for assembly of wheels to a motorcycle on the line before the wheels are spoked up, trued, and tyres fitted, as a silly-simple example), and all the non-vehicle items in the production process are present and correctly outfitted (tools like torque spanners, alignment jigs, bins for newly-introduced parts properly sized and located in the stillages at the correct assembly stages, etc.). As I mentioned, these were slow processes to assess that everything was right to produce the motorcycles and time was taken for measurements, installation of new tools or fixtures, and worker training. Then the results of the analyses done were returned to design engineering and production engineering staff for final validation and technical review. In theory, these motorcycles were fully to the specification of the motorcycles that were planned when full series production was to begin.
The final "preprod" stage was a batch of motorcycles that were built on the production line at full production schedule speed. These builds were done by the assembly line workers using the established production processes and they were timed to assure that the most efficient procedures were used to build the production motorcycles to the lowest cost and quickest time involved in the process. While there was some involvement of production engineering and production planning personnel, they were mostly involved in overseeing and measuring each process rather than being actually a part of the processes.
The finished motorcycles were mostly held for dispatch to distributors until series production had begun although there were cases where addition motorcycles were built at this stage to meet market demand. In the case of the introduction of the new models for production meant for January, 1972 -- the introduction of the Combat engine, the front disc brake, and the Interstate models -- there were a number of full-production pre-prod motorcycles built from October through December, 1971; some of these motorcycles were shipped to Australia, New Zealand, South Africa and other Southern Hemisphere markets so that they could be put into dealers' showrooms with timing to match their "selling season". Others were used to obtain the new processes instituted by mostly European governments for "Type Approval" of new models and for dealer stock for these markets, and more motorcycles than previously had been built for allocation to the N. American distributors (Berliner in the eastern US, Norton Villiers Corporation in the west, and Canadian distributors) so that the distribution "pipelines" in these markets could be filled for a more-than-adequate number of motorcycles to supply the expected sales of these new models. A brief look at production dispatch records and serial number batches indicates that at least 1200 motorcycles of the "1972 models" were built and mostly put into distribution prior to the actual start of production of the 1972 Commandos. If you include some early builds with standard engines (it was originally planned for the Combat engine to be an "option" at additional cost but market demand meant that this never really happened; also, the '72 model Hi-Rider Commandos were specified to have standard engines), it could be that the total number of these pre-prod '72 Commando could have reached 1600 - 2000 finished motorcycles -- prior to the "official" start of production of these models. This is very different to the earlier years when the number of pre-prod motorcycles probably did not reach more than 25 - 40 total of the three types, and it was not repeated in '73 due to a number of unsold Commandos in stock at the end of 1972 following the "Combat" engine failure and the fact that the 850 was not available for the beginning of production until the spring of 1973. A deep financial depression worldwide following the first major "Oil Crisis" also meant that production plans for 1974 did not call for a significant number of pre-prods.
The number of a significant pre-prod motorcycles in 850 Mk3 production in late 1974 prior to official start of 850 production again mirrored that experience from 1972 and produced the situation as described by Ashley in this video.