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Supercharged racing bikes


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#1 rotrax

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Posted 20 December 2010 - 12:46

I have an interest in the pre and post war forced induction race bikes that many factories built or planned to build. The magnificent restoration to full working order of the Velocette Roarer by Ivan and Graham Rhodes stands out and shows what we might have had but for the FIM. As many of you will know BMW and DKW led the way in Germany,while Rondine/Gilera flew Italys flag. The Velo was tried in TT practice by Stanley Woods and put to one side for the development that never came due to the war. AJS designed the Porcupine for supercharging and modified it for normal induction after the FIM ban. JAWA also followed this route and built a vertical twin with unit construction and supercharging. This proved to be NBG with normal induction and was abandoned. Any others? This short list,apart from the other Velo "Whiffling Clara" is the limit of my Knowledge. Over to you! Best Regards,In Sport, Rotrax.

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#2 Rennmax

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Posted 20 December 2010 - 13:11

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500 cc, 90 plus bhp, but way too heavy

Edited by Rennmax, 20 December 2010 - 16:58.


#3 terryshep

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Posted 20 December 2010 - 16:00

I have an interest in the pre and post war forced induction race bikes that many factories built or planned to build. The magnificent restoration to full working order of the Velocette Roarer by Ivan and Graham Rhodes stands out and shows what we might have had but for the FIM. As many of you will know BMW and DKW led the way in Germany,while Rondine/Gilera flew Italys flag. The Velo was tried in TT practice by Stanley Woods and put to one side for the development that never came due to the war. AJS designed the Porcupine for supercharging and modified it for normal induction after the FIM ban. JAWA also followed this route and built a vertical twin with unit construction and supercharging. This proved to be NBG with normal induction and was abandoned. Any others? This short list,apart from the other Velo "Whiffling Clara" is the limit of my Knowledge. Over to you! Best Regards,In Sport, Rotrax.

I also have a great interest in these bikes, the pre-war period was a wonderful period of innovation in racing. The DeKaVees have already been shown us by Herr Renn and as well as those you mention in the 500 class, there was the AJS Vee-4, which I believe is fully restored and living in Sammy Miller's museum. There was a Bianchi four and also the NSU twin. Then there were the Moto-Guzzi and Benelli 250 singles and even two 250 fours, one by Benelli and one by Gilera. Finally, built for 1940, there was a very modern looking 500 Moto-Guzzi triple with 80bhp at 8000rpm.

Looking at most racing bikes and how compactly built they are, squeezing in a fairly large blower and its drive, not to mention a plenum chamber and ducting, must have been quite a problem for those designers. Also, can't help thinking that those 250 singles must have given the expression 'turbo-lag' a whole new meaning!

#4 Rennmax

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Posted 20 December 2010 - 16:40

...... Finally, built for 1940, there was a very modern looking 500 Moto-Guzzi triple with 80bhp at 8000rpm.....



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Lovely patina

#5 terryshep

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Posted 20 December 2010 - 17:33

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Lovely patina

Patina's the least of it, Renn, lovely picture. Mine is in B/W from the other side. Not sure if I can legally publish it.

That front brake seems a little on the hopeful side....


#6 rotrax

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Posted 20 December 2010 - 22:59

I also have a great interest in these bikes, the pre-war period was a wonderful period of innovation in racing. The DeKaVees have already been shown us by Herr Renn and as well as those you mention in the 500 class, there was the AJS Vee-4, which I believe is fully restored and living in Sammy Miller's museum. There was a Bianchi four and also the NSU twin. Then there were the Moto-Guzzi and Benelli 250 singles and even two 250 fours, one by Benelli and one by Gilera. Finally, built for 1940, there was a very modern looking 500 Moto-Guzzi triple with 80bhp at 8000rpm.

Looking at most racing bikes and how compactly built they are, squeezing in a fairly large blower and its drive, not to mention a plenum chamber and ducting, must have been quite a problem for those designers. Also, can't help thinking that those 250 singles must have given the expression 'turbo-lag' a whole new meaning!

OOPS! Of course I should have remembered the AJS! I have seen it in Sams museum-was this the bike Walter Rusk had a fork link break while at full speed down the Clady straight? I also seem to recall the late Norman Webb owning a V twin supercharged 250 Rudge engine-was this a racer? In Sport, Rotrax.

#7 serafini

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Posted 21 December 2010 - 17:29

OOPS! Of course I should have remembered the AJS! I have seen it in Sams museum-was this the bike Walter Rusk had a fork link break while at full speed down the Clady straight? I also seem to recall the late Norman Webb owning a V twin supercharged 250 Rudge engine-was this a racer? In Sport, Rotrax.

Also 1930 Guzzi four and the watercooled 4 built by Dennis Jones just pre-War.

#8 billbomann

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Posted 21 December 2010 - 19:15

I had not realised that supercharged bikes were not banned immediately post-war.

Jock West won at Chimay on the AJS V-4, it is possible this was the last win by a supercharged bike?

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#9 Rennmax

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Posted 21 December 2010 - 22:49

The last wins and championships on supercharged bikes (Heiner Fleischmann on NSU, Georg Meier on BMW) in Germany were in 1950, because Germany was still banned from international competition FIM rules didn't apply.

Edited by Rennmax, 22 December 2010 - 21:17.


#10 billbomann

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Posted 22 December 2010 - 05:13

The last wins and championships on supercharged bikes (Heiner Fleischmann on NSU, Georg Meier on BMW) in Germany where in 1950, because Germany was still banned from international competition hence FIM rules didn't apply.


Many thanks for putting the record straight.


#11 terryshep

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Posted 22 December 2010 - 16:09

The last wins and championships on supercharged bikes (Heiner Fleischmann on NSU, Georg Meier on BMW) in Germany were in 1950, because Germany was still banned from international competition hence FIM rules didn't apply.

I read somewhere, Renn, that NSU got that blown twin going well enough to beat the BMW before they had to pack it in.

#12 Rennmax

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Posted 22 December 2010 - 16:59

I read somewhere, Renn, that NSU got that blown twin going well enough to beat the BMW before they had to pack it in.


Hi Terry, as far as I know Heiner Fleischmann only finished once ahead of Georg Meier, at Hannover Eilenriede in '50. IMO, the BMW was surely the better tool with a weight of 137 kgs, the NSU had at least 50 kgs more and a fuel consumption of 30 litre/100 km of alcohol fuel. The NSU might have had an advantage in power output ( 90-98 hp according to different sources), but then BMW had gained considerably more than 55 hp as the pre war version did. NSU had their share of success though in '56 with that engine, clinching the speed world record of 339 km/h at Bonneville.
Wilhelm Herz and Heiner Fleischmann took the 350 cc version (around 70 hp) to German championships in '48 and '50

Edit: Wonder what happend to Walter Moore after he left NSU shortly before the breakout of WW2 and returned to the UK . Anyone knows ? Thanks

Edited by Rennmax, 22 December 2010 - 20:55.


#13 Rennmax

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Posted 22 December 2010 - 18:41

nice little thing

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By courtesy of the Morbidelli museum

Looking at those supercharged bikes, I feel that the development of the chassis were far behind in comparision with the engines, even when this is not a plunger rear suspension. I once read that the engine and other crucial parts were hidden in a fountain when the factory in Pesaro was raided by German troops during the war...

#14 fil2.8

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Posted 22 December 2010 - 19:37

Very nice , :love: , thanks , Renn :up:

#15 rotrax

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Posted 22 December 2010 - 19:57

Very nice , :love: , thanks , Renn :up:

Hi, I am overwhelmed by the fantastic pictures and the knowledge of contributors to this post! Thanks so far- I wonder what else might come out of the woodwork. In Sport, Rotrax.

#16 serafini

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Posted 23 December 2010 - 17:08

I had not realised that supercharged bikes were not banned immediately post-war.

Jock West won at Chimay on the AJS V-4, it is possible this was the last win by a supercharged bike?

Posted Image

Nello Pagani won two races on the supercharged Gilera post War, in Switzerland - before Jock West's victory at Chimay I think but I have not checked.

#17 rotrax

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Posted 23 December 2010 - 19:02

Nello Pagani won two races on the supercharged Gilera post War, in Switzerland - before Jock West's victory at Chimay I think but I have not checked.

I started this post thinking I was the only one with an interest in these wonderful machines. I obviously misjudged it. If someone can let me know how to post pictures I may have something pretty special to put up re supercharged race bikes. Unfortunatly I am only handy with mechanical technology, not computers! Best Regards, Rotrax.