OzVMX Forum
Marque Remarks => British (BSA, Greeves, Triumph etc) => Topic started by: firko on November 08, 2010, 11:24:46 am
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It's easy to think that 4v twin exhaust port technology is a fairly recent thing. Not really, here's the hot new Ariel engine from 1932.
(http://img.villagephotos.com/p/2005-8/1062154/Ariel%2CVG32-SpecialFeatures.jpg)
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The old saying is 'there is nothing new under the sun'.
Probably the only real improvements in engine design were developed as a result of octane improvements in petrol, and also dramatic improvement in engine oils.
In the case of fuel improvers it doesn't seem that long ago [to me] that petrol came in 68 octane, changing up to 72 octane in time for the EK Holden which had its compression raised up to about 7.5:1 I think it was,to take advantage. My '54 model T110 {8.5:1 compression and cast iron head]which I had in '58 sounded like it was about to disintegrate if I let it idle. Thankfully it had manual retard with the Lucas racing magneto fitted to the model. I notice that on the model shown the cyl. barrel is not through bolted which indicates its comp ratio was probably about 5.5:1 to handle the fuel available. One can imagine the power of this thing if it had modern fuel and an appropriate comp. ratio! cheers pancho.
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Yes I believe 4v twin exhaust port technology was quite common in the 30’s.
I was watching Indiana Jones and The Last Crusade the other night and I was looking closely at the bike chase scene.
The two Dr. Jones were being chased by what seemed like the very same Germans that Colonel Klink used to man Stalag 13
(http://i15.photobucket.com/albums/a393/gmcloa/Misc/Indiana-Jones-2.jpg)
Looking closely at one of the 1938 chase bikes you can clearly see the twin exhausts forming into one.
How advanced were those pesky Germans back then, it would be many decades later when Honda would copy this very design for their XR range.
(http://i15.photobucket.com/albums/a393/gmcloa/Misc/Indiana-Jones-4.jpg)
(http://i15.photobucket.com/albums/a393/gmcloa/Misc/Indiana-Jones-5.jpg)
Sean Connery looks on in amazement at the leading axle front forks and alloy rim of another 1938 bike.
(http://i15.photobucket.com/albums/a393/gmcloa/Misc/Indiana-Jones-7.jpg)
No wonder Maico’s are so good if Germany was this advanced back then.
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And I would just like give a warning to everyone too.
I was quite unaware of this but when Indy pokes his jousting stick into the wheel of the pursuing German it can actually make a bike explode.
(http://i15.photobucket.com/albums/a393/gmcloa/Misc/Indiana-Jones-8.jpg)
(http://i15.photobucket.com/albums/a393/gmcloa/Misc/Indiana-Jones-9.jpg)
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Your just truely amazing Geoff.......how does he do it folks? ;D
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Thats right you only got to look inside a Adler engine, forks and shocks to see how far ahead the Germans were in the 50's, they were streaks ahead of the English bikes. Amazing stuff.
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yes lots of things on bikes are by no means first.
in 1910/12 Indian released their 8 valve twin cylinder 1000cc board track racers, i saw a 30's DKW factory special in the Birdwood museum with a supercharger on it. what does amaze me is that this early stuff never caught on till many decades after
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If we cast out minds back to the radical oval piston 8 valve two conrod NR500, exhaust on top 4 stroke GP bike, Triumph had been there first in the 1930s, I mean if both pistons come up to TDC at the same time you may as well join them together, pistons looked like sardine cans.
A lot of ideas are just waiting for their moment and superior materials and machine tools to become available.
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wonder how many of the limited release NR750's have actually been ridden?
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wonder how many of the limited release NR750's have actually been ridden?
I have actually seen NR750s on the road in Japan from time to time. They come up for sale but not my cup of sushi/
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ww2 stopped most of the development in most things auto as industry geared for armament.supercharged bikes got banned in road racing after the war
jim
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Well Indy hardly got any bites
How about something serious then
Adjustable shock mounts. It was probably a means of adjusting the ride height / hardness of the rear end rather than increasing travel.
(http://i15.photobucket.com/albums/a393/gmcloa/Misc%20bike%20stuff/BonanzaLaunch--9B.jpg)
Does any on know what year it was ?
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The first time I saw that rear unit adjustment device was on the model LE Velocette which would have been about '53. cheers pancho
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I think you are right Geoff, upright for a pillion or racked forward for a lightweight rider. Bike is about a 56 MAC Velocette. They kept this frame for all the Venom's and Thruxton's as well.
Grahame.
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And I would just like give a warning to everyone too.
I was quite unaware of this but when Indy pokes his jousting stick into the wheel of the pursuing German it can actually make a bike explode.
Very good tip, Geoffrey. And let's not forget that we learnt from The Mechanic that if you ride off a cliff on a 400 Husky you will also explode... and that many Germans chased around on Triumph twins during the Great Escape years....we've got a lot to learn...
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hey mustang graham do you have a Muzy 4 wheeler?