Sunbeam S7 Deluxe

1949 Sunbeam S7 Deluxe

The Imp had a granddaddy.
This is it....

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What's a Sunbeam motorcycle?

Where did the name "Sunbeam" come from anyway.  Legend has it that John Marston had built his first bicycle in 1887 and his wife remarked how the sun reflected off the black enameled frame of the bike.  In this story was the name "Sunbeam" born?  Marston was a japanner (metal laquerer) by trade, and due to his enterprising nature started his own company to build bicycles.  Being successful at bicycles, he moved into automobiles with the persuasion of his right-hand man Thomas Cureton.  The Sunbeam-Mabley was their first production "car" despite its unconventional diamond-shaped wheel layout.  Perhaps 100 or so examples were produced and sold.  Sunbeam Motorcar Company LTD was formed as a separate entity from John Marston LTD.  What put Sunbeam in the center of attention was the French Grand Prix in 1912, where three of the four Sunbeam cars entered finished 1st, 2nd, and 3rd.  This reputation perhaps earned Sunbeam Motorcar LTD some contracts for the war effort producing not only cars but motorcycles!  This is where things get interesting for me.  Marston had passed away by the time Rootes acquired the company, but Sunbeam had been involved in not only cars but these high quality motorcycles as well before World War 2.  Well after the war the Sunbeam motorcycles were spun off into the hands of BSA, while the automobiles stayed with Rootes.  We all know the story of the Sunbeam autos, but there's an interesting connection.  BSA with a vision of the future, set out to with the Sunbeam design team to create a totally different Sunbeam motorcycle than that of pre-war models.  This resulted in the specimen that now resides in my garage.

The Sunbeam S7 sports an all alloy overhead cam 500cc parallel twin motor with wedge combustion chambers, rubber mounted in an stout frame, linked to a shaft driven worm-drive unit.  What's that have to do with anything?  Well, when Walter Hassan chief engineer at Coventry had been tasked with finding an engine for a water pump, he looked at the reliable Sunbeam S7 engine for his inspiration.  This became the Coventry Climax Featherweight Marine Engine, which shares a lot of technology with the S7 engine: Inline vertical design, chain driven overhead cam, all alloy construction with steel liners, and an oversquare displacement yielding good power at high revs.  Later when designers from Hillman needed an engine for their new economy car (the IMP), they came to Walter Hassan's Coventry Climax water pump engine for their final choice.  So there we have it, its a small world sometimes (especially on a small island like England).  Even though the name is the same the Sunbeam IMP and Sunbeam S7 aren't really related until you look into the history.  The Sunbeam S7 could be considered the IMP's grandad.

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The History of KYL95

My wife Valerie has been involved with Sunbeams of the Rootes Group variety all her life.  Her first car was a Sunbeam (Hillman) Imp.  Which we still have and I have the joy of maintaining.  So, when I came along Sunbeams naturally interested me as well.  Being a Yankee from the coal mining regions of Western Pennsylvania my exposure to British marques was limited, so I had no idea of the lineage of Sunbeam starting with John Marston.  As I learned the history I discovered someone had already designed and built the perfect motorcycle.  This discovery came to me on Chris Gamble's "Classic Glory" website.  I thought the S7 was a superb design and by some means I HAD to have one.  Plus it was a Sunbeam.  By this point I had already settled for a modern shaft drive air-cooled Moto Guzzi California, figuring that an S7 or S8 would never come my direction.  The opportunity to own an S7 Deluxe presented itself last autumn.  A complete Deluxe appeared on eBay with what I thought was a reasonable starting bid.  Of course I got the argument from my wife, that I already owned two motorcycles.  The auction often entered my thoughts throughout the week.  It just so happened that this week was during our local Sunbeam car club national meet, which we call the Tigers East / Alpines East United.  (The name is a bit out of date because there are Imps, Rapiers, Talbots, and Venezias in the club as well.)  Anyway, there was an opportunity for us to Autocross our Imps.  Valerie was having so much fun and was so elated by the experience of racing, I thought that this was the perfect chance to bring up the subject of the S7 Deluxe on eBay.  Not a soul had put a bid on it, and this made me even more anxious. She was in such a good mood after the race (likely because her autocross time was better than mine), she shouted out a number as an agreement to place the bid. The auction was scheduled to expire at the same time we were due to be at the awards banquet.  I was NOT leaving that computer unless I knew the outcome.  With no mentionable competition at the last moment I became the victor!  I would have to wait a week before I could travel to
New Jersey to pick up this new treasure.  It was a complete bike and it actually ran, what better fortune could I have?

I employed the help of my biker mentor Stephen to travel with me to the Garden State.  It was going to be a whole day's travel up and back.  We met Dennis the seller at his home in the far north of New Jersey.  He rolled out the Deluxe and coached me on its operation.  Dennis is a great guy and even threw in some spare parts, and two books.  The fun part of owning something old, is knowing its history, especially when its an unusual history.

KYL95 had a hard early life.  From what we could tell, it was a motorcycle that was used in a practical manner.  It appeared to have traveled many country roads, as the British soil was still clinging to the underside of the fenders.  At some point in the 1960's good old Doctor Patt, a local veterinarian and motorbike collector, acquired KYL95 and imported it to the Gilbertsville Pennsylvania area.  Apparently Dr. John F. "Doc" Patt is somewhat of a legend in those parts.  As the story was conveyed to me, he just loved motorcycles.  He would get a yearning for a 6 cylinder bike and then buy one of each (a CBX, a Benelli, and a Valkyrie).  The same thing must have happened with the KYL95.  He needed one of each of the shaft drive classics.  He never registered the bike here in the states, as it probably didn't run right.  When he passed from this world it was found in his barn collection with 60-some other classic motorcycles.  I'm proud to now continue the story.

Dennis, a collector of Indians and other classics, persuaded me to honor the history of KYL95 and not restore it, but simply preserve it in an original condition.  I would renew the aged parts required for safe operation and no oil leaks, fore go paint and polish, and make it drivable and reliable.  The resulting affect would be of one awe when I show up at a bike show... "Wow a survivor and it actually RUNS!"  Once at my home Stephen and I got it running for a short victory drive through the yard.  It wanted to pop like it went lean, so I didn't push it.  We noticed that the oil and charge indicators didn't function.  So I had no idea if it was making oil pressure or not.  That was top priority, which turned into major catastrophe.  The engine barely reached 8 psi when stone cold.  So that meant I was getting my hands dirty.  Someone had been in this engine before.  The original front main bearing had already been changed out and there were shims under the big end shells.  After breaking one puller to remove the crank timing gear, I found the smoking gun that no one had discovered the first time.  A material failure had caused a chunk of the rear main to break off and get pulverized in the crank as it traveled to the big ends.  I got an unbelievable amount of pulverized bearing material out of the oil passageways.  Luckily, due to the oil pump design, and a good sump screen, the top end was spared of large particles of debris.

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Its been since 2008 since I brought KYL95 home, and stripped it down.  Today it looks basically the same, its clean, and doesn't leak, runs, and makes oil pressure. Read the whole rebuild preservation process starting HERE.

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