1962 BSA A65


1962 bsa a65, 1962 bsa a50, bsa lightning, bsa a7, bsa a10

1962 BSA A65 - NEW UNIT TWIN
After 15 years of great success with their pre-unit twins, the 500cc A7 & 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 & 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 & 650 twins a year ahead of them, with the 1962 BSA A65 & A50.

1962 bsa a50, 1962 bsa a65, bsa motorcycles, bsa lightning, bsa a65 pictures

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.


bsa 650, bsa lightning, bsa a65, bsa a50, bsa thunderbolt bsa engine, bsa motorcycle engine, bsa a65, bsa a10, bsa motorcycles 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


MODEL DESIGNATIONS:
1962 A65 650 STAR TWIN..........................................Standard Roadster
1962 A65 650 ROYAL STAR.........................................Premium Roadster


ENGINE:
Engine Type............................................................OHV parallel twin
Horsepower @ RPM..................................................38 @ 5800 rpm
Displacement...........................................................654cc
Bore.......................................................................75mm
Stroke....................................................................74mm
Compression Ratio...................................................9.0:1
Oil Capacity.............................................................3.4 liter/6 pints
Inlet Valve Diameter.................................................1.595-1.60"
Exhaust Valve Diameter.............................................1.407-1.412"
Valve Timing:
Inlet Valve Opens.....................................................51 degrees BTDC
Inlet Valve Closes.....................................................68 degrees ABDC
Exhaust Valve Opens................................................78 degrees BBDC
Exhaust Valve Closes................................................37 degrees ATDC

IGNITION:
Ignition Breaker Type................................................Lucas 4CA
Ignition Breaker Gap.................................................0.015"
Spark Plug Type........................................................Champion N4
Spark Plug Gap.........................................................0.025/0.64mm
Ignition Timing (fully advanced).................................34 degrees BTDC

CARBURETORS:
Type.......................................................................Amal Monobloc
Bore.......................................................................1-1/8"
Main Jet..................................................................310
Pilot Jet...................................................................25
Needle Jet.............................................................. .106"
Needle Position........................................................3
Slide.......................................................................389/3-1/2

TRANSMISSION:
Speeds.....................................................................4
4th - Top..................................................................4.35
3rd - Third...............................................................5.13
2nd - Second............................................................7.18
1st - Bottom.............................................................11.1

CLUTCH:
Type........................................................................Multi-plate, Wet
Primary Chain Type...................................................Tri-plex

CAPACITIES:
Petrol Tank:
UK ..models..............................................................4.8 US gal.
US models................................................................2.4 US gal.
Engine Oil.................................................................6pts/3.4L SAE 20W/50
Primary Case............................................................1/4pt
Gearbox...................................................................7/8pt SAE 90
Front Forks, per leg...................................................1/3pt SAE 10W/30

TIRES:
Front.......................................................................3.25 X 18" (21 psi)
Rear........................................................................3.50 X 18" (22 psi)

SUSPENSION:
Front.......................................................................Telescopic Forks
Rear........................................................................Swing Arm, 2 Shocks

BRAKES:
Front.......................................................................8"/20.32cm SLS
Rear........................................................................7"/17.78cm SLS

DIMENSIONS:
Seat Height.............................................................33.0"
Wheelbase...............................................................54.0"
Ground Clearance.....................................................7.0"
Weight, unladen.......................................................406 lbs.



Check out these great
BOOKS ON BSAs


BSA TWINS, A50 & A65 GOLD PORTFOLIO

BSA UNIT SINGLES

BSA UNIT CONSTRUCTION TWINS: COMPLETE STORY

BOOK OF BSA OHV & SV SINGLES 1945-1954

BOOK OF BSA OHV & SV SINGLES 1954-70

BOOK OF BSA TWINS, 500 & 650 1948-62

BOOK OF BSA OHV SINGLES 350 & 500, 1955-67

BSA & TRIUMPH TRIPLES

BSA OHV SINGLES

BSA BANTAM

BSA BANTAM BIBLE

BSA BANTAM, ESSENTIAL BUYERS GUIDE

BUILDING BUDGET BRITS: REFURBISH BSA & TRIUMPH

BOOK OF THE BSA-WORKSHOP MANUAL, PRE-1939

For more Great Books, please visit our
MOTORCYCLE BOOK STORE




HOME PAGE
Triumph Motorcycles
BSA Motorcycles
Norton Motorcycles
Matchless-AJS Motorcycles
AMC-Associated Motor Cycles
Royal Enfield Motorcycles
Ariel Motorcycles
Vincent Motorcycles
Velocette Motorcycles
Rickman Motorcycles
Japanese Motorcycles
Cafe Racers
Choppers & Bobbers
Rat Bikes
Classic Racing Motorcycles
Classic Motorcycle Auctions
Classic Motorcycle Shows
Classic Motorcycle Rides
Classic Motorcycle Restoration
Classic Motorcycle Shops
Classic Motorcycle Clubs
Classic Motorcycle Photo Gallery
Classic Motorcycle Events Calendar
Send us Pictures of YOUR BIKE
YOUR BIKE Pictures
About Us
Site Map
CONTACT US
Brit Iron Back Issues
Visit our STORE
Subscribe to our FREE e-zine & get a FREE 11X17 Poster
BACK TO TOP - 1962 BSA A65


1962 BSA A65
1/1/14




CLASSIC TRIUMPHS
2015 Wall Calendar

HISTORIC MOTORCYCLES
2015 Wall Calendar
ULTIMATE MOTORCYCLES
2015 Wall Calendar

Check out all our
MOTORCYCLE CALENDARS