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Discussion Starter #1 (Edited)
I think you're all aware by now of my lack of aesthetic sensibilities and good taste, for evidence you only have to
look at the thread I started some time ago showing you what my ideal bike should look like:

http://www.triumphrat.net/biker-hang-out/171494-is-this-the-perfect-motorcycle-it-is-for-me.html

I now invite you to feast your eyes on another of my favourites, one that I spotted parked near my place a few days ago. Coincidentally this bike is nearly as old as I am (but it's in much better condition than me :():

A 1953 NSU Max, a 250cc, 18bhp German motorcycle.

This machine was very advanced for its time, boasting a pressed-steel monocoque chasis and a single cylinder OHC
four-stroke engine of advanced design and good performance for its time, plus massive brakes, also unusual for the period.
Not surprisingly this is the bike that first inspired Soichiro Honda. If you doubt this check out the general look and layout of the very early Honda machines,
the Dreams, CB92, etc. They did not copy British bikes as it's often claimed.

This is an overall view of the left hand side. The weight-adjustable twin cantilevered-sprung seats and Victorian-style pinstriping, make it look ancient and rather quaint,
but do not be deceived, this is a very advanced motorcycle. Picture it with a normal dual seat and bright paintwork and it would look a lot more modern:



The next photo shows it from the right-hand side. Notice the leading link suspension that compensated and cancelled brake dive, ugly but effective fenders,
chain case, integrated pannier-toolboxes, clean engine lines with such details as wiring and HT lead covered by chromium-plated trunking:



A photo with detail of said chaincase showing the inspection/lubrication hole curiously placed to check the chain
tension on the top run of the chain, also check out the massive cast alloy rear shock anchorages, neat and beautifully engineeered snail-cam chain adjusters,
the split rear fender to facilitate rear wheel removal, this being made extremely easy by the knock-out spindle that allowed the chain to stay put during wheel removal, the ample toolbox, neat rear light, etc:



You might think this engine looks boring but it's nothing of the sort. The Germans and Italians tended to go for smooth enclosures and not the nut-and-bolt bitty look of the British.
It conceals a unique and very effective overhead camshaft drive system utilising two excentric conrods to transmit motion from the crank to the camshaft.
A bit like the conrods of a steam Railroad engine. It's called the ULTRAMAX drive.

No chains and tensioners, shafts or gears anywhere, silent running. It was also used on some of the company's cars
like the NSU Prinz. A masterpiece of engineering. Honda didn't dare copy that, but preferred to go for the cheaper chain drive and we all know the extensive catalogue of cam chain troubles they've had in the past.

For anyone intrigued by how this works here is a link that includes an animated GIF image:

http://www.nsu4.nl/english/e1ultramaxcamshaftsystem.html

A brief video of the system can be seen on Youtube:


Other details of note are the neat combined oil tank and air cleaner housing ( the tank is for the dry-sump engine: Try and spot the oil hoses. they're so neat as to be nearly invisible),
note that air filters were not common, at least on European bikes of the 50's and even the 60's. Even large powerful bikes like the Royal Enfield 750 Interceptor did not get one until 1969,
the intake air on the Max is circulated through the hollow chasis that also acts as an intake roar silencer, and the filter itself is oil-wetted and cleanable.

Notice the waterproofed separate float chamber carburetor, the left-hand gear change that became the World standard years later, the chrome cover over the exhaust pipe to conceal any blueing,
the footrests mounted on serrated shafts to enable 360 degree adjustment, and the 2-piece lightweight cast-alloy centre stand that is placed and constructed in such a way that it hardly lifts up the rear wheel
and so it's extremely easy to use. It is also placed at the balance point which enables front or rear wheel removal. Clever, eh?.

Also check out the helical geared primary drive, no primary chain nonsense there, the Interchangeable quickly-detachable wheels and brakes, grease nipples
fitted to every moving part, shafts, steering head, brake spindles, swingarm bearings, suspension joints, ...etc, etc.

 

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This is really interesting, Forchetto. A very cool bike---the 'locomotive-type drive' was neat. I certainly had no idea that was ever tried before in an auto or motorcycle.

Other than expense and perhaps the weight (maybe not such a problem for a single cylinder), I'm wondering what might be some of the additional downside to that sort of mechanism.

Did you talk to the bike's owner? Did you get to hear it running?
 

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Thanks for posting Forchetto, very interesting. The NSU has loads of great design features & quality engineering, well ahead of most, even into the 60s.

The cam drive looks very neat. Not likely still covered by any patents now I would think, so I wonder why it hasn't been used more recently? Maybe cost, but possibly manufacturing tolerances & difficulty with getting consistent alignment of the cyl head with the crankcase?
 

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:) If you think that's cool, then you should see the "Street Scrambler" they built in the late 50's. I saw one whilst on holiday in Bavaria a few years back. It was red and white with lots of chrome. One of the prettiest bikes I've ever seen, and very rare, seeing as I've never seen another. Hard to imagine that at one time, NSU was the world No1 motorcycle manufacturer! Here in the UK, they were very expensive, a 250cc Supermax was more expensive than a 650cc Triumph, so very few were sold. They were exceptionally well built though. Many years ago, I was in a now long gone Yamaha dealers, and the owner showed me his latest acquisition, a brand new, still in the crate, 250 Supermax, which he had found in Malta of all places! Lovely bikes!
 

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Discussion Starter #9 (Edited)
This is really interesting, Forchetto. A very cool bike---the 'locomotive-type drive' was neat. I certainly had no idea that was ever tried before in an auto or motorcycle.

Other than expense and perhaps the weight (maybe not such a problem for a single cylinder), I'm wondering what might be some of the additional downside to that sort of mechanism.

Did you talk to the bike's owner? Did you get to hear it running?
According to that link showing the animation, over 900,000 engines were made using that system, on both bikes and cars. The trick was to ensure the different expansion rates of the various components did not affect the valve clearances or distort components.

Somehow the valve train components are carried on a sort of sub-assembly that is pivoted to take up the expansion. I've read about it, but can't get my head around how it works.

I did get to talk to the owner but as he was having his lunch I didn't want to bother him too much.
 

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Thanks Forchetto,

That is very cool. A bit before my time by about 9 years or so. I remember some some of the first Honda's that looked like that, or very close. Later they started looking more like Triumphs.
 

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I did get to talk to the owner but as he was having his lunch I didn't want to bother him too much.
You are much more respectful than me. I would have said, 'Dude, you don't see an NSU everyday, let alone hear one. Quit stuffing your face get off yer arse and kick that bike over!'. :)

I'm going over to take a closer read of that website.....
 
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