1962 BSA A65

1962 BSA A65 - NEW UNIT TWIN
After 15 years of great success with their pre-unit twins, the 500cc A7 and the 650cc A10, BSA had a real challenge ahead of them. How do you follow up a 'home run' like the A7 & A10? They had proven themselves to be not only strong, but reliable (BSA's hallmark) with success on the racetrack and in the showroom. The pre-unit BSA twins were widely regarded as the epitome of the classic British vertical twin at the time. By 1957, Triumph MotorcyclesTriumph had converted its 350cc 3T to a unit-construction, followed by the 500cc twins in 1959. BSA being the parent company to Triumph must have felt a pressing need to beat Triumph to the punch with its big twins. Triumph was due to convert the 650 twins over to unit construction for model year 1963. So BSA made sure they introduced their new unit-construction 500 and 650 twins a year ahead of them, with the 1962 BSA A65 and A50.
ABOVE: Unfortunately, no suitable photos were available of a 1962 BSA A65. So this 1962 BSA A50, which is the 500cc version & almost identical in every other aspect, stands in. The most visual difference is that the A50 had a 7-inch front brake & the 1962 BSA A65 had an 8-incher. If you have a '62 A65, please send pictures of your bike.
ABOVE: BSA unit-construction A65 engine. This one is out of a '66 A65 Lightning (note the dual carbs). The engines remained essentially the same, externally from 1962 through the end in about 1972.

1962 BSA A65
THE BASIC LAYOUT

In a classic British move, BSA Motorcycles elected to build both their new 500cc A50 & their 650cc A65 to be basically identical in almost every way. This was done in an effort to save the costs of tooling & manufacturing different sets of components. So, aside from minor cosmetic variances, the only parts that weren't in common on the two bikes were the front brake (the A65 had an 8" SLS & the A50 had a 7") & the top end. Both models shared the same 74mm stroke, with a bore of 65.5mm for the A50 (yielding a displacement of 499cc), & 75mm for the A65 (for 654cc), slightly oversquare (very slightly, it was actually almost "square"), very unusual for a Brit bike at that time. Going Unit Construction not only cleaned up the lines of the bike, but it dropped 40 pounds off the weight. The new 1962 BSA A65 in single carb form made 38hp at 5800rpm with a compression ratio of 7.5:1. The engine followed the traditional British vertical twin layout: 360-degree crank (pistons rising & falling together), timing gears on the right, primary drive on the left & it followed BSA tradition by placing the camshaft behind the cylinders & running the pushrods up through a tunnel in the cylinder block. With the new unit design they tried so hard to 'clean it up' that they robbed it of much of its visual character. Whereas the old pre-unit BSA twins were handsome engines, the new A50s & A65s looked like bland lumps, the same on all sides. This was actually part of a clever plan BSA had hatched to be ahead of the rest of the world in adopting the "power egg-look". Why an engine should be made to look like an egg is beyond me, but this is the kind of thinking that ruined BSA in the years to follow.

1962 BSA A65 - NEW ENGINE
The conversion to Unit Construction, started with 1962 BSA A65 & it's A50 little brother, allowed BSA to make many other needed (and some not so welcome) changes. For instance, the rocker arms were now on shafts supported by lugs cast into the cylinder head, rather than in separate rocker boxes which were bolted to the head. It made for a much stiffer structure & because all the valve gear was contained in a cavity in the very top of the head & sealed by a one-piece aluminum cover, there were virtually no top end oil leaks. A very neat package, in this respect.
1962 BSA A65 - TEETHING PROBLEMS
In an effort to save a few cents (farthings), clever BSA used a copper-lead bushing instead of a main bearing on the timing side. These quickly wore out & caused lots of problems, and since the crankshaft received its oil supply from this location, the resulting lubrication problems caused engine catastrophic engine failures. It would be a few years before BSA would get it right. Today, if you have one of these early Unit BSA Twins, you can retrofit an upgrade to a roller bearing, if it hasn't been done already.

1962 BSA A65 - NEW FRAME & CYCLE GEAR
For the 1962 BSA A65, a new full double-crade frame was designed following the pattern of the previous A-Range machines. Partially welded, partially brazed lugs, it was heavily reinforced around the steering head & swing arm pivot, making for a very solid frame.


1962 BSA A65 SPECIFICATIONS

A65 Star Twin

A65 Royal Star

Engine type

Displacement

Bore & Stroke

Compression

Carburetor(s)

Ignition

Engine output

Primary drive

Clutch

Gearbox

Ratios, overall:

1st, bottom

2nd

3rd

4th, top

Final drive

Frame type

Wheelbase

Seat height

Ground clearance

Suspension, front

Suspension, rear

Brake, front

Brake, rear

Tire, front

Tire,rear

Fuel Capacity

Curb weight

Standard Roadster

Premium Roadster

Air-cooled OHV vertical twin

654cc

75mm X 74mm

9.0:1

1- Amal Monobloc, 1-1/8"

Breakers & coils, Lucas

38 bhp @ 5800 rpm

Triplex chain

Multi-plate, wet

4-speed constant-mesh, right-foot shift


11.0:1

7.18:1

5.13:1

4.35:1

Chain

Welded & brazed lug, full double cradle

54"

33"

7"

Telescopic fork, hydraulic damping

Swing arm, 2 Girling dampers

8"SLS drum

7" SLS drum

3.25" X 18" Dunlop

3.50" X 18" Dunlop

2.4 gal (US models); 4.8 gal (UK & export)

406 lbs

A WORK IN PROGRESS
In our efforts to complete our online index, and make this the world's greatest website about classic British motorcycles, we're building pages as fast as we can. The first thing we add are the pictures. Then come the specifications and then the history. So, if you see a page that just has only pictures on it, or just pictures and specs, please check back in a few weeks to see if we have it done. Thanks for your patience. And thanks for visiting Classic-British-Motorcycles.com. Please tell your friends about us.


MORE BSA PAGES:
BSA Motorcycles
..... BSA Gold Star
..........1939
..........1953
..........1954
..........1961
..........1962
..... BSA A7 (pre-unit 500)
..........1952
..........1955
..... BSA A10 (pre-unit 650)
..........1951
..........1954
..........1957
..........1958
..... BSA A65 (unit-construction 650)
..........1962
..........1963
..........1964
..........1965
..........1966
..........1967
..........1968
..........1969
..........1970
..........1971
..... BSA Rocket 3 (750 triple)
..........1969
..........1971
..... BSA Bantam


Check out these BSA BOOKS

BSA - THE COMPLETE STORY


BSA MOTORCYCLES: THE FINAL EVOLUTION


HISTORY OF BSA MOTORCYCLES


BSA: ILLUSTRATED MOTORCYCLE LEGENDS, by Roy Bacon


HOW TO RESTORE YOUR BSA ROCKET 3 & TRIDENT


CHILTON’S BSA MOTORCYCLE REPAIR & TUNE-UP GUIDE


BSA SINGLES 1945-1963 GOLD PORTFOLIO


BSA SINGLES 1964-1974 GOLD PORTFOLIO


BOOK OF THE BSA - OWNERS SHOP MA NUAL, PRE-WAR


BSA 350, 441 & 500 SINGLES, UNIT CONSTRUCTION 1958-1973


BSA CLASSIC MOTORCYCLES


BSA & TRIUMPH TRIPLES: GOLD PORTFOLIO 1968-1976


BSA UNIT SINGLES: COMPLETE STORY


BSA A7 & A10 TWINS, 1957-1962, by Haynes


BSA A50 & A65 TWINS: ALL MODELS


ILLUSTRATED HISTORY OF BSA MOTORCYCLES


BSA TWINS A7 & A10 1946-1962, GOLD PORTFOLIO


THE BSA GOLD STAR


MAINTENANCE MANUAL FOR BSA M20


SECOND BOOK OF THE BSA 500 & 650 TWIN 1962-1969


BSA PRE-UNIT SINGLES WORKSHOP MANUAL, by Haynes


TRIUMPH TRIDENT & BSA ROCKET 3 WORKSHOP MANUAL, by Haynes


BSA BANTAM WORKSHOP MANUAL 1948-1971, by Haynes


BSA UNIT TWINS, THE COMPLETE STORY


BOOK OF BSA SINGLES & V-TWINS 1936-1952


RUPERT RATIO UNIT SINGLE ENGINE MANUAL, BSA & TRIUMPH


RUPER RATIO, EVERYTHING BUT THE ENGINE, BSA & TRIUMPH


BSA A50 & A65 TWINS 1962-1973, Haynes Workshop Manual


BSA GOLD STAR & OTHER SINGLES, by Roy Bacon


BSA MOTORCYCLES SINCE 1950,BR>

BSA UNIT SINGLES OWNERS WORKSHOP MANUAL #127, 1958-1972, by Haynes


BSA TWINS 150 & 165 GOLD PORTFOLIO, by RM Clarke


ILLUSTRATED BSA BUYER’S GUIDE, by Roy Bacon


BSA BANTAM, by Owen Wright


BSA PRE-UNIT TWINS, by Mick Walker


BOOK OF THE BSA OHV & SV SINGLES - 250cc 1954-1970


BSA TWINS & TRIPLES, by Roy Bacon


TRIUMPH & BSA TRIPLES: THE COMPLETE STORY


BOOK OF BSA TWINS, ALL 500 & 650 1948-1962, by Floyd Clymer


BOOK OF THE BSA OHV & SV SINGLES 1945-1954: 250, 350, 500 & 600


BSA BANTAM BIBLE, ALL MODELS 1948-1971


WHERE BSAs DARE: BSA’s 1952 ISDT GOLDS & MAUDES TROPHY


ILLUSTRATED MOTORCYCLE LEGENDS: BSA, by Roy Bacon


BSA BANTAM ESSENTIAL BUYER’S GUIDE


BOOK OF THE BSA BANTAM


BSA 500 & 650 UNIT TWINS, Clymer Repair Manual


BSA COMPETITION HISTORY


BSA MOTOR CYCLING ANNUAL, 1937, Kindle






Please visit our
MOTORCYCLE BOOK STORE


Take a tour of our site...

HOME PAGE
Triumph Motorcycles
.....Bonneville
.....Tiger
.....Trophy
.....TR6
.....TR7
.....Trident
.....X-75 Hurricane
.....6T Thunderbird
.....5T Speed Twin
.....Daytona
.....Twenty-One
BSA Motorcycles
.....A65
.....A10
.....A7
.....Gold Star
.....Bantam
.....Rocket 3
Norton Motorcycles
.....Commando
.....Atlas
.....Dominator
.....Manx
Matchless-AJS Motorcycles
.....G3
.....G9
.....G12
.....G80
AMC-Associated Motor Cycles
Royal Enfield Motorcycles
.....Interceptor
.....Bullet
Ariel Motorcycles
.....Square Four
.....Red Hunter
Vincent Motorcycles
.....Black Shadow
.....Comet
Velocette Motorcycles
.....KSS
.....LE
.....MAC
.....Thruxton
Rickman Motorcycles
Japanese Motorcycles
.....Honda
.....Kawasaki
.....Suzuki
.....Yamaha
Cafe Racers
....Triumph Cafe Racers
.....Norton Cafe Racers
.....Other Cafe Racers
Choppers & Bobbers
.....Choppers
.....Triumph Choppers
.....BSA Choppers
.....Rat Bikes
Classic Racing Motorcycles

Classic Motorcycle Events
.....Auctions
.....Shows
.....Rides
Classic Motorcycle Restoration
Classic Motorcycle Shops
Classic Motorcycle Clubs
Classic Motorcycle Photo Gallery
Send us Pictures of YOUR BIKE
YOUR BIKE Pictures

HOME PAGE
.....About Us
.....Site Map
.....CONTACT US
.....Please visit our BLOG
.....Subscribe to our FREE e-zine BRIT IRON
.....BRIT IRON E-zine Back Issues

Visit our STORES
.....Motorcycle Books
.....Motorcycle Magazines
.....Motorcycle Calendars
.....Motorcycle Helmets
.....Motorcycle Rain Suits
.....Motorcycle T-Shirts
.....Whitworth Tools
.....GoPro Cameras

Crazy about cars, too? Check out our sister site:
www.American-Muscle-Cars.net

Back to top - 1962 BSA A65
5/5/16

Learn how to BUILD YOUR OWN WEBSITE, like I did.