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Unusual engine capacities

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#1 Graham Clayton

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Posted 11 October 2012 - 08:42

In 1962 Jim Redman started the 350cc GP season on a Honda with a capacity of 285cc, before finishing the season with the 339cc RC171.

I presume that the 285cc engine was a bored out version of the RC163 250cc racer, and that no more capacity was available.

285cc is a very unusual engine capacity. Have there been many other examples in GP history of engines that were under the cc capacity for a class by a considerable margin?


#2 GD66

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Posted 11 October 2012 - 09:06

The 297cc Honda "350" six and the 300cc "350" MZ are the two that first spring to mind. Also the prolific "Fablon" specials of the 1970s certainly added to the size of GP and national fields.... I refer of course to a number of Yamahas entered as having 251cc or 254cc alleged capacity.

#3 Rennmax

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Posted 11 October 2012 - 10:39

The MV triple in '66 had a capacity of 420 cc (first race in Assen) till the Senior TT in autumn. The MV four in '73 had a capacity of 433,5 cc (Paul Ricard, Salzburg) the first real 500 cc engine rode Read in Hockenheim.

#4 SMonty

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Posted 11 October 2012 - 11:14

The last ever winner of a world championship status 500 grand prix on the Isle of Man.......

......Tom Herron on a 351cc Yamaha!

#5 rd500

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Posted 11 October 2012 - 11:27

yamaha raced the 251cc v4s for a few races in the 350 class, mang also used a 351 kawasaki in some of the 500gps of 82 and aprilia had the 400/420 and 460cc bikes for the 500 class. hans becker had a modified 250 bored out to 360 by hummel for the 500 class in 1991.

if its gps then you cant forget the roton, which was 588cc in the 500cc class but got away with it as its a rotary engine

ah the days when it was interesting.....

#6 fil2.8

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Posted 11 October 2012 - 12:48

ah the days when it was interesting.....

and had full grids ........................................................ :rolleyes: :well:

#7 Geoff E

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Posted 11 October 2012 - 16:35

Not a bike but a car ... an "overnight rebore" and rebuild to get into another class!

"On 31 May 1939 just before the outbreak of WWII driving his special engineered MG, in Dessau, Germany, Goldie Gardner took the 750cc up to 1,100cc class records over 2 kilometres, 1 mile, and 5 kilometres distances, at average speeds of 203.5 mph, 203.3 mph and 197.5 mph respectively. After an overnight engine rebore, on 2 June 1939 at the same venue he gained the 1,100cc to 1,500cc class records over the same distances at average speeds of 204.3 mph, 203.9 mph and 200.6 mph."

In 1947, they set 750cc records, then later ran the 6-cyl engine with pistons 2 and 5 removed to get 500cc records. :)