Many of you remember the Munch Mammut, we’ve written about them several times on The Kneeslider, they were a fascinating motorcycle from the 1960s powered by an NSU auto engine. Very impressive engineering at the time but they looked a little ponderous, after all, that 4 cylinder engine wasn’t designed to fit into a motorcycle, what would you expect?
A few days ago, Mick King sent me a note from British Columbia, Canada, with some info and photos of a Norton special he put together in the early 1970s. What makes this Norton stand out is the powerplant, it’s a 1000cc air cooled inline 4 cylinder NSU auto engine, shades of the Munch Mammut, but this Norton seems anything but huge, actually, the engine fits in there quite well and it’s testament to Mick’s engineering that with the Norton transmission behind it, wouldn’t look out of place in any late 70s or early 80s era superbike.
Mick worked for an NSU dealership in England back in the 60s when he first saw the air cooled fours. He thought they would make a pretty impressive motorcycle engine, but it was little more than a dream at the time. A few years later, he moved to Canada and saw quite a few of those NSU cars driving around and very able to reach 100mph, his dreams of engine transplants returned and he began planning. He obtained the frame from a 1968 Norton Atlas, had it shotblasted to ready it for the project and started lining things up.
Mounting the engine in the frame went much more smoothly than he had anticipated, unfortunately, mounting the transmission was another story altogether, requiring switching the transmission around and driving it from the opposite side. A Kawasaki distributor was then modified to work in reverse rotation and the kick starter was reworked, as well.
The old NSU engine was rebuilt with all of the updates the auto engines had received up until that time. The forks and rear shocks were swapped for Commando units and a seat from a Norton Interstate was installed which seemed a better visual fit than the original.
Mick says that even with all of the modifications to the engine and a new ignition, the bike fired up on the first kick, which surprised everyone. He quickly ran through some carb adjustments to smooth it out, hopped on the bike and took it for a maiden run.
The eventual top speed of the bike was 125 mph. The 1000cc engine runs 4 Amal concentric carbs, 10.5:1 compression and puts out 70 horsepower. It may not be a lot by today’s standards, but back in the early 70s, that was a very impressive beast, not to mention the overall build which took a lot of initiative and ingenuity. The whole project took only around eight months from start to finish working part time!
The Norton NSU looks a lot more nimble than the Munch Mammut and is currently on display at Trev Deely’s motorcycle museum in Vancouver.
Nice work, Mick and thanks for sharing!