Small Italian bikes

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Nice vid, thanks for posting. I too like the small italian bikes, athough i have always been a Britbiker.
While we all appreciate our big Nortons/BSA's/Triumphs etc, it must be said that the British motorcycle industry was not noted for its lightweight machines.
Rattly Villiers engined two strokes, or BSA bantams hardly qualify as desireable machines today, well.. at least for me.
The italians did a better job, although these bikes had their flaws too, like poor electrics, (Lucas stuff looks like a marvel of engineering by comparison).
 
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While that is true about small italian bikes, and no comparable brit tiddlers, someone has written a book on british racing 250cc bikes.
Haven't got the title to hand at the moment, but they pointed out that something like 57 (?) varieties of brit bikes had raced in the 250cc class.
Including quite a number of fancy little twins and fours - can't recall if there were any triples in there.

Comment was made that if brit roadbikes had showed the same variety and flair for design, there were a few winners there.
But none of the big factories would turn them out for sale....

Seem to recall that the Rudge Rapid (250cc) of the early 1930s was noted as a real gem.
But production didn't continue, in the face of Rudges financial difficulties.
A common theme with british motorcycle makers of the time.

Q. How do you make a small fortune out of making motorcycles ?
A. Invest a large fortune in them...

The Italians were noted for their stylish design in small bikes, where the brits seemed to just throw them together and think that was good enough (?).
And the Italians were also noted for the lovely finish of their castings, and the attention to detail in doing so.
Cheers.
 
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I think the Aermacchi Ala D'Oro 350 was one of the best bikes ever made.
 
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The fellow who did up the slimline Triton I have raced Triumph 500s back in the day- said the little Duc 450 singles would give him a run for his money on the track.
 
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Aco, great video, thanks. Lots of interesting bikes. It brings me back to when a bunch of us competed in our local hill climb in the late 70s/early 80s. We rode our street bikes to these events, stuck a race number on the headlamp and off we went. The yellow Desmo Duke in the video was just like mine 30 years ago.

The 350 Aermacchi over-the-counter racers were real thoroughbreds. They were still being raced here in the early 70s in amongst the Yam two strokes and not doing too badly. I used to race against them in the 80s on my Duke single and they gave me a hard time. They were superior in every way to Ducatis which, even if they were ohc, were mostly road bikes converted by amateurs on tight budgets (like yours truly). Only a few pros knew how to get the best out of them at top level back in the day (apart from the factory during the 60s), one of them being Reno Leoni.
 
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A friend used to race a 250cc Ducati which had the lot done to it - GP carburetor on methanol, welded up 12 to 1 piston, twin plugs and racing cam from the factory. I rode it once at Calder race way. It was like a kiddies' pram with 100 BHP. It was however unreliable. It was as quick as the TD2s for the first few laps at a race meeting then it slowed, we could not find the reason. I've raced against 350cc Ducatis a few times in the old days, with my 500cc Triton - hard to beat a good guy on one. An Aermacchi 350 is a completely different kettle of fish. I knew a guy who use d to own the Linto 500 - coupled 250cc Aermacchis. It sounded great however there was always that weakness in the mainshaft coupling between the two motors. The 450 Ducati is a good bike however I suspect the c pacity is too large for the rest of it.
In the old days were were all mad on big bikes, and I think we missed out on a lot of fun. About 6 years ago I saw a fifties Moto Morini 250 single which had been converted for road racing - that was pretty inspiring.

Have you seen this ? there is a version in English somewhere:

http://vimeo.com/3895328

Here in English :

http://www.spike.com/video-clips/tck8or ... -collector
 

xbacksideslider

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Ducatis - Dr. Taglioni didn't know much about how to design an intake or exhaust port or combustion chamber.
Ports came in low and at right angles to the cylinder, always a bad idea. Hair pin valve springs were a dead end too. Must have been a design theme - keep the head short in height.

The rest of the engine's design was just fine, even great. Simple functional beauty and well executed.
The chassis too, superior yet minimal.

Same head/ports on all of em. The 250s could breath, the 350s could be made to breath . . . . sort of, short rod narrow cases for the 350s. Good fuel important too. The 450s made OK dirt bikes because they could only breath at lower engine speeds, so cam and compression optimized for that.
 
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I think the ducatis were much lighter than many other bikes, quick mainly for that reason. The fast 250 that I rode scared me , I wasn't used to anything so nimble. There is still a 250cc Parilla production racer here, and several of my friends have ridden it. It is notable because everyone who has ridden it has crashed and not known how it happened. One split second all is going well, the next you are on the ground.
 
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xbacksideslider said:
Ducatis - Dr. Taglioni didn't know much about how to design an intake or exhaust port or combustion chamber.
Ports came in low and at right angles to the cylinder, always a bad idea. Hair pin valve springs were a dead end too. Must have been a design theme - keep the head short in height.

The rest of the engine's design was just fine, even great. Simple functional beauty and well executed.
The chassis too, superior yet minimal.

Same head/ports on all of em. The 250s could breath, the 350s could be made to breath . . . . sort of, short rod narrow cases for the 350s. Good fuel important too. The 450s made OK dirt bikes because they could only breath at lower engine speeds, so cam and compression optimized for that.

Does this mean the Desmo 250 / 350 s too :!: :shock:
 
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xbacksideslider said:
Ducatis - Dr. Taglioni didn't know much about how to design an intake or exhaust port or combustion chamber.
Ports came in low and at right angles to the cylinder, always a bad idea. Hair pin valve springs were a dead end too. Must have been a design theme - keep the head short in height.

The rest of the engine's design was just fine, even great. Simple functional beauty and well executed.
The chassis too, superior yet minimal.

Same head/ports on all of em. The 250s could breath, the 350s could be made to breath . . . . sort of, short rod narrow cases for the 350s. Good fuel important too. The 450s made OK dirt bikes because they could only breath at lower engine speeds, so cam and compression optimized for that.
Does that follow thru to the L twins? as I think they are just two 350's/450's commoned up?
 

xbacksideslider

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The desmo technology's great contribution is to control valve float by capturing the valve against the cam; this enables almost square edged cam profiles with radical starts and stops that are impossible with spring cams/valves. The point is that this allows cam timing effectively to be stretched with very steep opening and closing ramps. So . . . . yes the desmo system helps the low angle of attack ports by allowing more air flow within any given cam's opening durations. There is more air under a square curve than under a sloped curve.

The wide case desmos disappointed compared to the earlier narrow case engines, in part in my opinion, because they went to a long rod and the engines, while gaining longevity and high speed durability, lost their "snap." Also, those bikes were a few pounds heavier and when you are dealing with low HP to start with, every ounce matters disproportionately in terms of power:weight.

And, yes, regarding the L twins, the ports/combustion chamber are similarly flat in entry/exit and the same thing happens, the 750, as two 375s runs well - at that displacement, they heads are at about the limit of what they can flow to run out to the RPM limits of the pistons/rods and so on. When they pushed the displacement up to 900cc it became a torque monster unable to spin out absent radical cams, which the desmo system, with its potential for very sharp opening and closing ramps can/does deliver.
 
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There seems to be a choice to be made about the revs at which power is to be delivered, perhaps it depends on what sort of gearbox you have ?
 
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Desmodromics were used to good effect in small capacity class racing in Italy back in the day for engine braking on the overrun, when the revs would soar, thus controlling valve float.

If the Desmo system in the 250/350 singles still conferred a significant performance advantage over the conventional valve spring heads, you would see a lot more of them in classic racing, and you don't. If you look at the top racing Ducatis like those prepared by Nigel Lacey in England, they use heavily-modified valve spring heads in which the ports have been re-shaped. In this year's Classic TT in the Isle of Man, a Lacey-prepared 350 Sebring (very much a 'cooking' engine as standard) won the Privateer 500 class, at a race average of over 98 mph over a distance of 150 miles - and no desmodromics! A friend of mine who campaigns a decent 450 valve spring race bike saw what Lacey did to his cylinder head and was quite surprised at the surgery that had to be done. You can get the 450s to go well, and the factory certainly did, but they can become grenades. I wonder how many sets of crankcases the factory went through with its works racer…

Ducati used the Desmo to gain a marketing advantage over the opposition for their road bikes. Since they were the only production machines to have the system, and since there was a mystique surrounding it, they were seen as unique, exotic and desirable.
 

Time Warp

.......back to the 70's.
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xbacksideslider said:
And, yes, regarding the L twins, the ports/combustion chamber are similarly flat in entry/exit and the same thing happens, the 750, as two 375s runs well - at that displacement, they heads are at about the limit of what they can flow to run out to the RPM limits of the pistons/rods and so on. When they pushed the displacement up to 900cc it became a torque monster unable to spin out absent radical cams, which the desmo system, with its potential for very sharp opening and closing ramps can/does deliver.
There was little point to being able to rev to the moon as the 750 GT - 860 GT and 900 GTS were all tourers.
Even the Desmodromic 900 SD was debatable as it was a tourer encumbered with heads that required looking after and that in itself effected its ability to be simple tourer long term.
The 1979 900 GTS might have been one of the best all rounders built by Ducati.
Although I have been hands on with beveldrives for 30 + years quite often 'desmo has been a PITA on occasion,a lot of complication for some 52 rwhp in the case of the 900 SD.
Even today there could be a market for a non desmodromic Ducati.

Don't forget the triple cam singles.

http://www.bevel-enthusiasm.com/image/p ... oanime.mpg
 
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Perhaps we should repeat the story of Paul Smarts' win in the Imola 200, 1972 was it.
On the race desmo v-twin.

Maggie Smart, his wife, accepted the offer for him to ride a Duc in the race.
(She was Barry Sheenes sister)
He didn't want to go, but needed the money, so turned up.
He didn't know the Duc at all, and said that down the back straight he put it in 3rd, and just pegged the throttle to the stop.
After several laps of this, he decided it just wasn't going to blow up.
So finished the race, and won.
To the eternal gratitude of Ducati....

Desmo was good for something.... ?
 
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