There’s a certain quality and star status afforded classic motorcycles with girder forks. Partly it’s because many date from a ‘Golden Age’ of motorcycles when there were dozens of manufacturers with very different ideas on design, but mostly because girder forks just don’t exist on new bikes these days.
But girder forks give a motorcycle eligibility for some very special road events such as the Banbury Run (1930 and before) and the annual Giants Run in Dorset organised by the local Vintage Motor Cycle Club section.
That’s a long way to get around to admitting I have a soft spot for 1930s era motorcycles (and cars come to that). I keep a look out for suitable candidates among the various auctions that come up, but for one reason or another have yet to secure the right bike.
Another chance has just come up, so I’m putting in the time to research and getting ready to bid.
It’s a 1928 BSA Sloper, a 493cc overhead valve single-cylinder motorcycle. BSA’s ‘S’ Sloper series is so-called because the engine cylinder is canted forwards which, coupled with a ‘saddle’ petrol tank, means the seat height is surprisingly low. The first models had a single port head but later bikes, including this one, have a twin port exhaust with pipes run down either side of the bike ending with spectacular fishtail silencers.
There’s also a hand gearchange, mounted on the right side of the petrol tank but otherwise the controls are recognisable.
The auction blurb from H&H Classics says the bike hasn’t been run for a while although the engine does turn over and has compression. It will need a degree of recommissioning. But hey! this is a motorcycle that’s almost 100 years old and, at some point, was subject to an extensive restoration. How bad can it be?
So what kind of price will it achieve at the auction? Kind of hard to be exact because there’s no doubt values of old British bikes have been falling for a while, while other more modern classics, such as the Kawasaki Z1000 and Honda CB750, have risen.
One Sloper sold earlier this year with H&H Classics for £5,290 incl buyers premium. That was an older restoration but had an amazing history file. It included the original sales invoice dated 2nd of July 1928 from dealers Hieatt and Argyle in Oxford. That shows the BSA cost £71 19 shillings and 9 pence when new, including the optional Lucas Magdyno and horn. Insurance wasan extra £2 15s 9p. There was also a small photo showing what appears to be the first owner sat on it in 1930.
Digging further, I then came across a YouTube video posted by Bonhams for the exact same motorcycle that’s being sold by H&H Classics in July – the very bike I’m interested in.
Bonhams said about the bike when it came up for auction with them in 2021: “A 1929 model first registered in December 1928, this overhead-valve Sloper was purchased by the vendor’s late father in 1995 and subsequently restored.
“Kept in a dry heated garage, the BSA was last used in 2012 and is presented in very good condition throughout. The machine is offered with a quantity of expired MoTs; an old V5; and a current V5C document. It should be noted that this motorcycle has been stamped with two frame numbers: ‘P7358’ and the non-factory ‘RD723224’, the latter being that recorded on the V5C.”
The Sloper, reg DS 9564, sold for £9,775 incl premium in Bon hams’ July 2021 sale at Stafford. Hmmm… that’s a bit on the steep side for me but perhaps it will fall somewhere between the two.
This 1928 BSA Slope will be for sale by auction at the H&H Classics sale on 9 July 2025 at the National Motorcycle Museum, West Midlands.
1928 BSA Sloper
