1938 Scott Flying Squirrel

Photos of Scott Flying Squirel for guidance in my rebuild

1938 Scott Flying Squirrel

Whenever I source a vintage bike as you have seen previously I build a record of detailed photos of the condition of the bike as required which is in valuable in assisting the the total refurbishment

The photos below have been taken in no particular sequence

History of Scott Flying Squirrel

I thought it appropriate that a statement should be included about the origins of this bike

The Squirrel name was used for Scott motorcycles since 1921 but with the death of the founder Alfred Angas Scott in 1923 the unorthodox Scott two-stroke motorcycles began to become more conventional. Development of the three-speed Scott Flying Squirrel began in 1922 as the company was in severe debt and faced receivership. Launched at the 1926 Earls Court motorcycle show, the Flying Squirrel was expensive - nearly twice the cost of a sporting four-stroke motorcycle of the time.[1] The unique water-cooled circulation used a convection method known as the thermosyphon system. The bottom end block was painted either green or red for racing or road respectively and featured a centrally positioned flywheel, twin inboard main bearings, overhung crankpins and doors to enable ease of access to the engine. The redesigned three-speed gearbox, multi-plate clutch and the repositioned magneto were all significant improvements.[2]In 1929 Scott achieved third place in the Isle of Man TT and launched a road going TT Replica Flying Squirrel. Following cost cutting the factory also launched a basic touring model in 1929 for under £70. Financial problems continued, however, and in 1931 Scott were unable to enter the TT or the Earls Court show. A three-cylinder prototype was developed but Scotts lacked the resources to develop it and on the outbreak of World War II production ended.[1]

Between 1935 and 1938 the factory at Shipley in Yorkshire produced the B2592 air-cooled Aero engine, based on the Scott Flying Squirrel motorcycle unit.[3] A 25 hp (19 kW) version was also specifically developed to power the notoriously dangerous Flying Flea aircraft.[4] In 1950 the rights were bought by the Birmingham based Aerco Company and in 1956 they produced what are known as the Birimingham Scotts.[1]

Scott Flying Squirrel review

The Scott Flying Squirrel was a motorcycle made by The Scott Motorcycle Company between 1926 and the outbreak of World War II. With its optional full-frame gas tank, a nod to the works racers of the day, the Super Squirrel was launched at the 1925 Olympia Show, followed in 1926 by the Flying Squirrel. Subsequent improvements included the addition of a duplex frame, bigger brakes, and magneto power. By the 1930s, the Flying Squirrel took on more of a touring role, being further updated with detachable cylinder head, Brampton forks and a foot-change gearbox. Efforts were made to develop three-cylinder models but they came to naught. Production ceased during WWII and did not resume until 1946 with the relaunching of the Flying Squirrel. However, only a few years later, in 1950, the company ran aground financially. By 1956 there was renewed hope when Matt Holder bought the Scott rights. He added a new plunger rear suspension, twin front brakes and telescopic forks to the original design. However, the committed effort to revive the Scott brand faded away in the late 1960s. © motors-bay.com

Start of the refurbishment

It is worth the trouble to alaways show photo of the bike as purchased, inthis particular case a word of mouth purchase from a guy who was chasing Nortons in America and came across the Scott which was of no interest to him I made a deal immediately and had to wait 12 months to import from San Francisco. Worth the wait. Photo as bought is below followed by series of photos detailing all sections of bike.

Starting the refurbishment

There is a need to ensure you can work safely on dismantling and therefore it is imperative to position bike on robust stands and lifting tackle, the photos below demonstrate how I commenced.

Seat

The bike as purchased had the seat anchored directly on to the back guard and in my view, not very practical with no springs. I played around with various options but at time of writing I was undecided as to a satisfactory solution, nevertheless, it is worth recording with the inclusion of photos.

I decided on the following seat mounting which is more in keeping with the original concept.

Radiator

The water cooled radiator has a damaged header tank and is a soldered honeycomb tube radiator, very difficult to find an oganisation to attempt a repair. I eventually located Aussie Desert Coolers who have maintained the skills of this dying art form.

Front forks

The forks are air sprung and oil damped and are manufactured by Dowty Olematic. There is an air leak and this necessitated a total dismantling and the manufacture of a small jig to facilitate this. I have been very fortunate to source original seals from the UK.

I as always take many photos to record the work done and also it assists in the reassembly, below are photos of the fork main mountings.

I polished the fork yokes and will leave it with the bronzed look.

Magneto

The magneto functions perfectly and only needs refurbishment which meant cleaning and painting.

The end result I am happy with.

Mounted refurbished magneto.

Engine and gear box removal

This proved to be not such a simple task but persevered and ended with engine separated from gearbox and in a stand on bench.

Head removal

Unable to separate head from block with jigs or brute force, read some forums and this is a common fault, decided not to try anymore.

Have had real difficulty in trying to separate the head from the block, eventually engaged Crankshaft Rebuilders to solve the problem. They also experienced difficulties with eventually determining that the problem was the radiator feed pipe which had been a previous cowboy job and incorrectly assembled. Drilled out and then we were able to separate. What I then requested was for a total refurbishment to be carried out i.e. gudgeons, bushes, pistons, rings and cylinder honing.

It was necessary to source new pistons, rings, gudgeons, circlips and a full gasket set. My source for these items are Scott Parts UK and eventually arrived (COVID obviouly caused delays

Crankshaft Rebuilders did a great job but also a long time waiting but worth it, pistons purchased specifically to match re bore were 74.5mm. Photos below show results. Separating the head from block was a nightmare, I had to drill out all head studs and it still would not separate. Eventually determined it was the water jacket pipe which was butchered by people unknown and had been driven into block. Drilled this out which allowed separation and then manufacture of a correct threaded alloy insert.

Engine assembly

Block had been bored to 73.5mm with new rings to suit. First job was to set ring gap clearance which is calculated by multiplying your bore size by 0.004in. This will give you the top ring gap you are looking for. The best way to arrive at the correct gap was to place a file in the vice hold ring and draw against vice until correct gap is established by placing in bore, see below.

Gear box and clutch

The only trouble I found I was missing roller bearings (3/16") five on clutch primary drive, gear selection firm with no play and no damaged gears.

Refurbished gear box and clutch

Replaced roller bearings and cleaned components.

Removal of con rods

Removed pistons and con rods with the intention of removing flywheel, had extreme difficulty trying to separate flywheel from casing even with my press. Decided to only clean and repaint flywheel as flywheel bearings appeared OK.

Commenced reassembly

Rigged frame to start the rebuild with engine assembly first followed by the gearbox and back guard.

Bought headlight and speedo manufactured brackets and mounted also battery and regulator on manufactured platform together with manufactured rear stand and keeper.