The Gilera 500cc Grand Prix bike of 1957 was the final version of a bike with a decade of world championship-winning development behind it, making it one of the most desirable racing bikes in history.

The factory Gilera team dominated the first decade of world championship motorcycle racing, winning the premier class in 1950, 1952, 1953, 1954, 1955, and the factory finished racing at the end of 1957 after winning the championship one last time.

Only 15 factory 500 racing bikes were built, and the surviving factory Gilera fours from the period are now in museums or closely held in private collections, and are rarely offered for public sale.

Until now, that is. A genuine 1957 factory bike preserved through being sold to Geoff Duke's racing team in the early 1960s has emerged as part of a single-owner collection to be offered at RM-Sotheby's Villa Erba sale on May 27, on the shores of Lake Como, Italy.

The collection is headlined by the historic 1928 Brough Superior SS100 "Moby Dick," which leads a series of five bikes from the famed British manufacturer – we covered these bikes in a feature article last week.

Plagiarism is the ultimate compliment

So rare and sought after was the Gilera 500 racing bike that, like many cars where demand vastly exceeds supply, perfect replicas are now available.

In the case of the Gilera, those exact copies are produced by MV Meccanica Vergerha in the United Kingdom. They're made to order, so you can still buy one new from MV Meccanica Vergerha with the price around £90,000 (US$116,000).

Formerly known as Kay Engineering, the company is well known for its replicas of significant racing machinery, and has now produced six 1957 Gilera four replicas, and several of these replicas have previously sold at auction.

This one sold for £84,000 (US$138,667) at Bonhams' Stafford in April, 2011.

This one fetched £76,300 (US$112,184) in April, 2009 in the aftermath of the global economic calamity.

The most recent sale of a replica was during the sale of the Robert White Collection in London on September 19, 2016 when the bike sold for £55,200 (US$71,600).

Those are quite spectacular prices for bikes with no provenance, so the authenticity of this bike and the fact that it was a genuine factory racer can be expected to make a world of difference on the auction block. RM-Sotheby's official estimate of the price is €380,000 to €450,000 (roughly US$400,000 to $500,000).

Now the provenance of this bike prior to Scuderia Duke is unknown – how much of a part it played in Gilera's successes of the fifties is unclear. What is known, though, is that it was one of three bikes provided by Gilera for the 1963 Grand Prix season, and although it had not been developed in any way during the six years since the factory pulled out of racing, it was still very competitive.

It wasn't a match for the rampaging MV Agusta of Mike Hailwood, but the bike did manage a string of impressive placings, with eight podiums in 1963 including one win in the hands of John Hartle in the Dutch 500 TT and second place in the first five races of the year, before a string of crashes and mechanical breakdowns soured the year.

Hence this bike has almost certainly been ridden by Hartle, Phil Read and Derek Minter at Grand Prix podium level during its second lifetime.

This is the last of the pre-MV era world title winners. After Gilera pulled out of world championship competition, MV Agusta won 17 straight 500cc world titles.

And another one might not become available for decades.

You can find the auction link here.

View gallery - 22 images