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Inside

Moto Guzzi

Special

Booming Italian let

loose in Somerset

Truly Matchless

Super-rare 750cc twin on the road

Continental

lifestyle

Reader’s lifelong passion

for Enfield’s sweet 250

FEBRUARY 2018 | modified triumph 650 | team obsolete | enfield continental | matchless 45 | wasp motorcycles | vintage trikes | fit electronic ignition | sunbeam project | issue #457

PLUS

20 pages of

Classic

World

News

B r i t a i n ’ s b i g g e s t - s e l l i n g c l a s s i c b i k e m a g a z i n e

subtle sensation

Stealth

Triumph

Beautiful TT replica hides cunning

upgrades for our modern world

Britain’s forgotten 1000cc twin

160mph Trident outfit ¤ Salon Moto Legende

Vintage trikes tear up Brooklands

Swiss JAP Special ¤ 50 years of Wasp

Inside Team Obsolete

Workshop

Project Sunbeam

Electronic Dominator

Enfield frame

Feb 2018 UK Jan 24-Feb 20

£4.30 USA $9.99


The

issue

Two fingers on the

clutch? You’d want

more than that on

an earlier Jota...

Sound

The

speed

of

words: Phillip Tooth.

Photography: tim keEton

Velocity is intoxicating, but when it’s combined with a noise that sounds

like a portent of the world’s end, it can only be one thing – a Laverda Jota

70

71


laverda jota

1

2

T

o say that the Jota comes with a

reputation is a massive understatement.

When it was launched in 1976, it was the

fastest road bike that money could buy.

While the Ducati GT I owned at the time

was good for about 115mph and my Le Mans’ top speed

was closer to 130, the legendary Jota was the first overthe-counter

production road bike to top 140mph. It

didn’t matter if it was too heavy and that you had to

bully it round bends, or that you

needed two hands to pull in the

clutch lever, the Jota blew the best

from Japan into the weeds, and

deafened them in the process.

Laverda’s 981cc triple had

launched itself from the Breganze

factory in 1973 with the uninspiring

model name 3C (Tre Cilindri). With

a bore and stroke of 75 x 74mm and

featuring the usual chain-driven

double overhead cams with two

valves per cylinder, designer

Some advertising lines are just hype – but not this one

Luciano Zen went his own way

with a 180° crankshaft. Because the middle piston was

at top dead centre when the outer pistons were at

bottom dead centre, the 3C wasn’t as smooth as a 120°

triple like a Triumph Trident, but it certainly wasn’t

rough – and the power pulses gave the exhausts a brutal

bark. Laverda claimed 80bhp at 7250rpm and a top

speed of 137mph... but you could take those figures with

a large grind of black pepper.

It was British importer Slater Brothers who unleashed

the Beast of Breganze. Richard and Roger Slater had

‘the Jota blew the best from Japan

into the weeds – and deafened

them in the process’

On the gas with the

fastest bike of its

generation

been campaigning a 3C in production racing with some

success. Fork triple clamps from the SFC750 endurance

racer twin were used to give a shorter rake. The engine

delivered extra punch, thanks to a factory cam and

pistons designed for the endurance racers that first

appeared at the Bol d’Or, and the silencers lost their

baffles while the collector pipe was a bit bigger. Those

mods were enough for another 8-9bhp at peak revs, and

that meant harder acceleration. In 1975 Slater Brothers

built a small number of these

racers for the road, and called

them the 3CE (‘E’ for England).

Tested at the Motor Industry

Research Association track, the

latest Laverda recorded a mean

average speed of 133.3mph.

The Breganze factory had also

been busy, upgrading the 3C with

Laverda’s own cast wheels, triple

Brembo discs and a tail fairing to

produce the 3CL for the 1976

season. This was to be the bike

that the Slater Brothers would use

as the basis for the Jota, a name that music-loving Roger

chose after hearing Spanish folk dance songs with a

three/four beat – and they didn’t hang about.

Available from January 1976, the Jota’s engine was

factory-built to Slater’s 3CE specification. The

transmission featured a lower first gear ratio (9.51:1

instead of the 3CL’s 11.24:1) and closer ratios for the

other four, which made the Jota racetrack-ready and a

great bike to ride on fast, open roads. Claimed

maximum power was now 90bhp at 7600rpm. And that

1: High, wide,

handsome –

and very fast

2: Pumper

Dell’Ortos feed

in the fun juice

3: Adjustable

handlebars and

Japanese clocks

are quality touches

4: Just so as you

know what’s

overtaking you

5: Looks like a

silencer – but looks

can be deceptive...

was enough for a two-way average of 137.80mph, with a best

one-way of a benchmark-setting 140.04mph.

Those first Jotas were available in either red or green paint for

the tank and side panels, with a black frame. Silver was the

colourscheme for 1977, with gold an option the following year,

when the Ceriani suspension was replaced by Marzocchi.

Laverda’s official orange race livery and a silver frame graced the

Jota in 1979. For 1980 the cylinder head was redesigned, the

exhaust headers were increased to 36mm diameter and the

clutch got extra plates. There were more changes in 1981, when

the Series II Jota got a bigger-output alternator (up from a barely

adequate 140W supplied by Bosch to an impressive 240W

thanks to Nippon-Denso). The transistorised ignition was

moved to the left side of the crankshaft, and the primary

chaincase grew a bulge as big as mamma’s pasta pot to hide it.

Almost as important, the clutch cable was replaced by a

hydraulic system. The big news for 1982 was a new 120° crank,

but a year later the Jota was replaced by the RGS.

I’d have been happy to throw my leg over any Jota, but the

pick of the bunch has to be the 1981 orange-and-silver version

that owner Terry Sage wheels out of his garage before handing

me the ignition key. Before hitting the starter, I used to openand-close

the twistgrip on my Le Mans so that the pumper carbs

would squirt neat petrol into the combustion chambers. The

Jota also wears pumper Dell’Ortos, but Terry does things

differently. “Just pull back the choke lever a bit and press the

button. It’ll fire immediately, then ease the choke right off.”

The Jota’s soon ticking over reliably. It’s my first surprise.

This Jota is full of surprises. The second is that I can plant

both feet on the ground. The seat height might be a crotchstretching

32in, but the nose of the seat and the rear of the tank

are both slim. I think it was journalist Peter Watson who

described the Jota’s Brevettato ace bars as ‘adjustable to 27

different configurations, none of them comfortable’ – and I still

laugh whenever I see a Jota and think of him. Yet as soon as I set

off, I feel completely at home, easing through rush-hour traffic

and out of the city as if I’d owned this Jota as long as my Duke.

After a quick blast along a dual carriageway, I change down

23

4

5

73


1 laverda jota

into third entering a village and rumble through with

rock-steady needles recording 30mph and 2000rpm on

the Japanese clocks. Read that again: third gear, 30mph,

2000rpm. I didn’t believe it, either – and had to play

with the gearbox to make sure that I was right. Wasn’t

the Jota meant to be a right pain in the neck – and

wrists, and clutch hand – to ride slowly, and only come

into its own when you were thundering across England

at speeds close to twice the legal limit?

But when I crack on, the Jota begins to reveal its true

nature. The engine growls, the exhausts boom and as the

needle swings past 6000 my guts tell me that things are

getting exciting. The Jota can be safely revved to 8500,

but with 500rpm in hand that’s still 60 in first, nearly 90

in second and 110 in third. Two more gears to go...

You don’t ‘think’ a Jota through bends. At 236kg

(522lb) with a gallon of super unleaded, it weighs the

same as my old GT – but most of that weight is carried

much higher. Stay focused. Get your braking done early

and pitch it into the corner. Winding on the throttle

helps to pick the Jota up again and throws it out of the

apex. You’ll have to use muscles you forgot you had, but

it feels good. Who needs a gym when you’ve got a Jota?

On fast sweepers the steering is faultless. You can

relax at 70mph with the engine turning over at a lazy

4000rpm, or cross continents at the ton and still only be

using 5700rpm. Gears snick effortlessly into engagement

and the hydraulic clutch feeds the power in smoothly.

Brake and clutch levers were set up by Ricardo Oro’s

workshop in Breganze, so they are as good as you can

get, but after riding for four hours the thumb muscle on

my left hand was aching and I didn’t like the front brake.

Although it was powerful enough, it had as much feel as

squeezing a pick-axe handle. And the lever was too far

from the handlebar for the span of my dainty paw.

There was time for some cornering photos before we

headed home, and that meant turning around in the

road a half-mile from the bend. We were in the middle of

the country and there was only one house, so I didn’t

think we would disturb anyone, but I was making the

fifth turn when an old woman came out and said

politely: “You are making an awful lot of noise. Can you

please do that somewhere else?” Pointing out that I was

only using half-throttle wasn’t the way to respond, so I

apologised and we moved on. The Jota legend lives.

‘It’s special’

Terry Sage bought and fixed up a

crash-damaged 1976 Laverda 3CL

when he was 19. “I’d been riding

the 3CL for four years, but I really

wanted a Jota. When I saw a

secondhand orange-and-silver one

at Three Cross Motorcycles in 1985

I had to have it.” Terry was working

as a steel erector at the time: “I was

earning good money, but it cost

£3500 so I had to go to the bank

and get ticked up to the eyebrows.”

He was still running his Jota in

1998, but was being left behind by

his mates who were all riding

modern supersports. So he sold the

big triple and bought a Ducati 748.

“I realised I’d made a mistake as

soon as I sold it,” says Terry. He

chopped in the 748 against a 996,

then a 999 and finally 1098S – but

he still hankered after a Jota. “I

know it was loud, heavy and slow

compared to modern sports bikes,

but it was something special.”

He bought another Jota, but had

top-end oil feed problems. Ged

Shorten at GCS found that the six

long studs which fix the cam

bearings, cylinder head and barrel to

the crankcase had been fitted

upside down. As they were

tightened, some of the threads had

been ripped from the crankcase.

The studs are 9mm diameter and fit

in a 10mm hole. Oil is pumped up

the gap to feed the cam bearings

but now the lubricant was simply

returning to the sump.

After the crankshaft was rebuilt

by Keith Nairn of Laverda Scozia,

Ged repaired the crankcase and

rebuilt the engine using Omega

ceramic coated pistons.

With the Jota properly sorted,

Terry is enjoying the good times

again. “My friends all admit that she

can get a move on for an old girl!”

‘The engine growls, the exhausts

boom, the needle swings past

6000... things get exciting’

The legend lives on –

and Phillip survived

the experience, too

74


going native

The Bravest Indians

The recent revival of the Indian marque has brought it back into the

spotlight, so here’s a reminder of its first incarnation. We look at

some of the legendary models that forged the famous firm’s identity

words & Photographs: phillip tooth

▲ 1905 Camelback

On May 24, 1901 Oscar Hedstrom sent a telegram to George Hendee to

tell him that the first Indian was finished. Six days later he was riding the

prototype around Springfield before towing his friend Brooks Page, who

was on a bicycle, up a long hill. Hedstrom’s engine had a capacity of

260cc and was fitted into a bicycle frame, with chain drive and a top

speed of 25mph. The first production Indian was assembled at the

Springfield factory and was on the road in May 1902, with a total of 143

built that year. Three years later a bigger single-cylinder engine rated at

2.25hp was offered, with a bore and stroke of 67 x 82.5mm adding up to

a capacity of 290cc. When this 1905 red Indian (a colour option to the

standard Royal Blue) was first pedalled into life, there was a spring fork

and a twistgrip control to the carburettor. Production rocketed to 1181 in

that year. Speed had increased dramatically and a tuned version covered

the flying mile at 52mph. That was really flying...

▲ 1912 Hedstrom Racer replica

Headline news in 1906 was the addition of the 633cc V-twin racers to the

catalogue, soon followed by the road version (still with a camelback tank).

A single-loop cradle frame replaced the bicycle-style diamond frame in

1909, and there was a coiled spring in a cartridge mounted horizontally

above the mudguard to provide suspension for the forks (although the

famous leaf-spring forks were introduced for the 1910 season. There was

also a new 988cc F-head engine with a mechanical oil pump, and these

engines were reduced to 585cc to make them eligible for the 1911 Isle of

Man Senior TT, the first time the race was run over the Mountain course.

With all-chain drive, a clutch and a two-speed gearbox the red Indians

swept the board with a 1-2-3 finish. At the end of 1911, Indian held all 121

American speed and distance records. For the motodromes, Hedstrom

developed an eight-valve engine but these rare beasts were for the

chosen few. Mere mortals used a tuned F-head like this 1912 racer replica.

1917 PowerPlus

When a road tester arrived back at the Indian experimental department

after a hard, fast ride Charlie Gustafson, who designed the new V-twin,

and Frank Weschler, in charge after founders Hendee and Hedstrom had

retired, stubbed out their cigarettes and walked out to meet him. “What

does she go like?” asked Gustafson. “Man, this motor has power –

plus!” replied the tester. The 998cc side-valve used the same 42° V-twin

angle as the Hedstrom engine. Two years of rigorous testing were

carried out before it would go into production in 1916, but to prove just

how good the Powerplus was, Erwin ‘Cannonball’ Baker fitted a

Powerplus engine to his 1914 Hedstrom chassis to attack the Three Flag

record by setting the shortest time to ride from Canada to Mexico. He

left Vancouver on August 24, 1916, reaching Tijuana on August 27 –

1655 miles of treacherous roads in three days, nine hours, 15 minutes.

“It’s a bear, a big, husky lick-all-comers machine!” Baker enthused. That

rugged useability led to Indian supplying the US Army with nearly 50,000

Powerplus motorcycles after America entered World War I.

▲ 1917 PowerPlus Boardtrack

Somehow, Charles Franklin managed to extract more power out of a

Powerplus engine than Harley’s top tuners could squeeze out of their

eight-valve engines. While the 1917 road bike now featured leaf springing

front and rear, the earliest board track and dirt track bikes used a cut-down

frame and were often raced in rigid form. Later there would be special

Marion frames for the Powerplus racers. The tube that ran under the

engine on the loop cradle frame was cut out, and the engine held in place

with steel plates. It seemed like a backward step when these bikes were

debuted at the 200-mile national championship race in Marion, Indiana in

1919, but the pundits were proved wrong. A Daytona version of the

Marion frame, complete with lowered top tube and headstock, was

adopted in 1920. These frames are easily recognisable because the seat

tube had to be bent into an S-shape in order to make the engine fit

properly. The Daytona soon became the factory riders’ favourite bike, but

there were plenty of farm boys and garage mechanics who raced

stripped-down Powerplus cycles.

ABOVE: Spring forks

went on road bikes;

racers were rigid

both ends

RIGHT: Rugged

but tuneable

Powerplus engine


going native

xxxxxxxxx xxx xx xx

xxxxx xxx xxxxx xx

▲ 1930 Scout 101

‘You can’t wear out an Indian Scout’ was the boast long before the 101

was launched in the spring of 1928. Capacity had been hiked from the

original 600 to 750cc for the 1927 Police Special, and it was this ’45 cubic

inch’ engine that went into the 101. One of the best Indians ever, the new

Scout was about 3in longer, 1in lower at the saddle and even had decent

brakes. Big ‘balloon’ tyres were standard and handling exceptionally good.

For 1931 there was a twistgrip-controlled oil pump to vary the delivery rate

of lubricant. The 75mph 101 Scout was popular for amateur racing and

Wall of Death. Despite the Depression, some 14,000 were sold before it

was (unpopularly) replaced by the 203 Scout – a 750cc using the heavy

Chief chassis – in 1932. The sporting image was regained with the 1934

Sport Scout – a winner for Ed Kretz at the first Daytona 200-miler in 1937.

▲ 1938 Type 438

There was a new four-cylinder engine for the 1936 model year, but it was

a flop. Called the ‘upside-down’ engine because the exhaust valves were

now on the top, it looked ugly and the high exhaust pipe needed a steel

guard to stop it burning the rider’s leg, so for 1938 the Model 438

reverted to the original overhead inlet/side exhaust configuration. The

cylinders were now cast in pairs – testing proved that eliminating some of

the air gaps between cylinders allowed the heat to be pulled into the

airstream more quickly. The aluminium cylinder heads were detachable

with the valve mechanism fully enclosed and automatically lubricated.

There was a streamlined muffler to keep things quieter on this 95mph

motorcycle. Although a left-hand throttle and right-hand gearshift was

standard, a right twistgrip and left gearshift was a factory option.

ABOVE: Indian Big Chief

was a response to the

1200cc Harley

▲ 1925 Big Chief

For the 1920 season a radically different Indian was launched: the 600cc Scout, with semi-unit construction – the engine,

primary drive, clutch and gearbox were locked together. The primary drive consisted of three helical gears, each on roller

bearings, all enclosed in an oil-tight alloy casing. Instead of a single camshaft to operate all four valves there were now two

camshafts, each with a single-lobe cam to operate both inlet and exhaust valves of one cylinder through pivoted cam followers.

Heads and barrels were cast in one piece. The double-loop cradle frame had a flat platform to mount the engine/transmission.

But there were those who demanded more power. Enter the Chief, launched on Labor Day, September 1921. The 998cc

engine delivered about 20hp, enough for brisk acceleration to a top speed of 65mph. But Harley had gone supersize with a

1200cc engine in 1921. The Chief was more technically advanced, but Indian needed something bigger for the 1923 season –

enter the 1200cc Big Chief. In November that year Hendee Manufacturing Company became Indian Motocycle [sic] Company.

▲ 1925 Ace Sport

What’s Ace got to do with Indian? Rather a lot. William Henderson, the

technical brains behind the Henderson Four, had fallen out with Ignaz

Schwinn, whose Excelsior company had taken over Henderson in 1917.

Henderson found new backers and formed the Ace Motor Company in

Philadelphia in 1919, with the first high-performance F-head Aces rolling

out for the 1920 season. But then tragedy struck. In 1922 William was

killed while test riding his latest creation, the very rapid Sporting Solo

model Ace. Ace riders set new cross-country speed records and won

numerous hillclimbs, but financial troubles were never far away. In

December 1927 Indian purchased the Ace assets and marketed the

1300cc Four as the Indian Ace, and up to 1935 all Indian Fours were

essentially Ace, which were essentially Henderson...

▲ 1929 Type 401

While Indian initially produced the Ace virtually unchanged, the 1929

Model 401 adopted more of the parent company’s trademark features.

As well as deleting the Ace name, the tank became a compact teardrop

design. Indian’s famous leaf-spring fork replaced the Henderson-Ace

plunger type and a drum front brake was fitted, complementing the

contracting-band rear. The 401 initially shared the Ace’s single downtube

frame, but vibration issues prompted a twin-tube design based loosely on

the Scout models but using heavier tubing. The new frame was fitted to

the Model 402, available from spring 1929, which also featured a fivebearing

crank to replace the Ace’s three-bearing unit, along with a better

oil pump, redesigned cylinder heads and alloy pistons. The 402 gained

50lb, so riders needed all the available 30hp to stay with the old Ace.

ABOVE: Military Chief

boosted 1940

production

‘These 75mph bikes

were painted in a drab

olive with no hint of chrome’

▲ 1940 Military CHief 340B

Although the US Army selected Harley-Davidson for World War II, in 1940 Indian received an order for 5000 Chief sidecar

outfits from the French army. When events overtook France, most were diverted to other forces, including the Polish Army,

many ending up in Britain - some allegedly ending up at the bottom of the North Sea in torpedoed ships. These 75mph bikes

were painted a drab olive with no hint of chrome, but at least the dispatch riders had the comfort of plunger rear suspension.

41


going native

▲ 1942 Scout 741B

The British, Canadian, Australian and other Allied forces chose the Indian

Model 741B to be used alongside BSA M20 and Norton 16H dispatch

bikes. Designed in 1939, with a capacity of 500cc, the 741B was lighter

and almost as fast as its bigger brother. It revved to almost 5000rpm and

topped out at 65mph. Production ran through to 1944, with about 35,000

made. After the war, many – like this 1942 model – were stripped of their

army uniform and dressed for Civvy Street with a coat of fresh paint.

▲ 1943 Type 841

In 1941 the US Army offered Harley and Indian a $350,000 contract to

build 1000 shaft-driven 750cc twins to rival the WWII BMW. Harley’s XA

was a boxer, but Indian offered a transverse 745cc V-twin., using Sport

Scout cylinders. Put through their paces in summer 1942, Army testers

reckoned the low-centre-of-gravity 841 handled better than the H-D with

a 70mph top speed. A tough call, but there could be only one victor... the

Jeep. They were sold off as war surplus in 1944 for $500 each.

▲ 1946 Chief

If Indian couldn’t compete with Harley’s Knucklehead in the performance

stakes, the 80mph Chief certainly could when it came to style. The big

news for 1940 was the skirted fenders introduced by engineer and stylist

George Briggs Weaver. Although not everyone was impressed with the

look, there were others who thought the skirted fenders made the Chief

the most beautiful bike on the planet and today they are iconic Indian

wear. Also new that year was a plunger-sprung frame, although the forks

retained the leaf spring – that all changed in 1946, however. Indian had a

new owner named Ralph Rogers; times were tough and the Chief was

the only model produced that year, but it came with a new double-spring

girder fork with a hydraulic shock absorber, basically a slimmer version of

the fork developed for the military 841. The Indian head and war bonnet

fender light was introduced for the 1947 model year, but Rogers’ business

was struggling – he was developing a range of lightweight vertical twins

to take on the Brits and finances were tight. The Chief wasn’t listed in

1949, but returned in 1950 with new telescopic forks and a capacity hike

to 1300cc. Three years later production of Indian motorcycles ended and

the Roadmaster Chief was sent to the happy hunting grounds. But today

the Chief and the Scout are back – big time. And you can even buy one

with skirted fenders and that war bonnet light...

▲ 1947 ‘Rainbow’ Chief

In 1933 the Chief went to dry sump lubrication from the old total loss. A

year later it lost the helical-gear primary drive, replaced by a cheaper and

quieter four-row chain – Harley riders joked that the whine from the

geared primary drive sounded like a built-in police siren. The 1935 Chief

looked bang up to date with smooth ducktailed fenders and a striking

Indian chief‘s head decal on the tank. Performance was improved with

cylinder heads designed to increase midrange torque with a small

sacrifice in top speed. But Harley had their own ideas, and in 1936

launched the legendary 1000cc ohv ‘Knucklehead’. Indian’s response?

A tank-top instrument panel and custom paint features – but these did

become a useful selling point, with colour options running to practically

anything the customer wanted. This was a side benefit of Dulux paint

manufacturer E Paul duPont having taken over struggling Indian in 1930.

In 1938 Rollie Free set stock class records at Daytona Beach with

109.65mph for the Chief and 111.55mph for the Sport Scout.

‘harley riders said The primary

drive sounded like a siren’

42


Workshop

Spannering supremo

Rick Parkington welcomes you

to our Classic Workshop

88

Rick’s Fixes Your problems solved 92 Project bike Martinsyde cases 98 Wiring Pt2 Looms for beginners

classicbike.workshop@bauermedia.co.uk


our classics 1?????????????

Workshop

Rick’s

how to

Make vintage bike grips

You can adapt a regular handlebar grip like this...

Fixes

Solving the problems

of the classic world

1Here’s the problem – most handlebar grips have a closed end. If you

have a vintage bike with inverted levers – or a more recent bike with

handlebar weights – you need to make a neat cut.

2

A

knife makes a mess of the job, but a wooden or nylon bar makes

it easy to use a wad punch – the bar gives the necessary support

of an ‘anvil’ against which the punch can do its work.

If the bolt doesn’t fit

the hole, it’s worth

making one that does.

“Clacka-tacka-tacka-tacka-tacka-tacka…”

stammered the Sunbeam’s engine as I peeled off

the main road into a lane. Oops, that doesn’t

sound good. It’s engine speed… piston? Big end?

It’s loud, so more likely piston, but (despite

having opened up a bit to shake off a tailgating

car) there’d been no sign of any seizure.

I limped gently along, home still ten miles

away… Try a hand-pumpful of oil. No

difference, hmmm... I’d expect a splurge of cold

oil to take the edge off a noisy big-end or

piston. Try a bit of ignition retard; taking the

punch out of the combustion usually quietens –

or at least alters – rattles. Not this time...

RICK’S patch

Not as bad as it sounds

A ride on Rick’s latest acquisition results in a noise that sends alarm bells ringing...

‘it would be Just my

luck to blow it up so

soon after buying it’

Who Is Rick?

Rick Parkington

has been riding

and fixing classic

bikes for decades.

He lives and

fettles in a fully

tooled up shed in

his back garden.

My thoughts turned to the events I’ve

booked the bike in for this year – and

what I’d take instead. Just my luck to

blow it up so soon after buying it;

whatever the trouble it can be fixed,

but it will take time and money.

Spotting a lay-by, I pulled in for a

quick look and bingo! The rocker

support plate bolts had come loose, allowing

the rockers to jump about on the head; the

noise was that and the consequent slack in the

tappets. After a few spanner tweaks, we

completed the journey in (relative) silence.

Back home, instead of simply reaching for the

Loctite I had a closer look and the true cause of the

problem became clear. One hole in the side plate is

oversize and a loose fit on the bolt. Without the location

of being a snug fit in the hole, the clamping force of the

bolt will struggle to hold it from shifting and working

loose. I made a shouldered bolt and hopefully that will

be the last I hear of that problem.

ILLUSTRATION: iain@1000words.fi

3Lucky me, I have an arbor press which makes it simple, but a

hammer would also do the job. It may be necessary to turn the

punch after the first blow to ensure a clean cut all the away round.

THE BIG FIX

Do the maths

Bob Covey emailed with what he called a

‘simple’ question. “Rick, my BSA B44 is

stripped for rebuild. It should have a

compression plate, but I can’t find out

what thickness it should be for the correct

9.4:1 ratio. Do you know, or can you tell

me how to work it out?”

I don’t know – and I failed maths

O-level twice before giving up. But thanks

to mechanical problems like this, I’ve

picked up a bit since.

To work out the compression ratio, you

need to know the volume of the

combustion chamber at TDC, measured

by tilting the engine and filling the plug

hole to the bottom threads with a

Higher-tuned Victor had a scary 11.4:1 compression ratio

measured quantity of oil. This, added to

the swept volume of the cylinder and

divided by the combustion volume, will

give you the ratio. For example, if the

combustion volume is 100cc on a 500cc

engine, 100 + 500 = 600. Divide that by

100 and you get 6, or 6:1.

4There we go – a nice, neat job that doesn’t look like it has been

chewed out by mice. One other tip: hairspray makes a good

lubricant for handlebar grips and sticks ’em in place when it dries.

So can you adjust the equation to work

out the combustion volume from the CR

and the capacity? Suppose the 441cc BSA

chamber was 50cc, then 491/50 gives a

ratio of 9.82:1 – close. Trying again, I find

52.5cc chamber volume would give a

441cc engine a 9.4:1 ratio. The next thing

is to work out by how much volume is

increased by, say, a 1mm shim. The B44 is

79mm bore, so using Pi x R sq x H, we

can work out that a 79mm x 1mm

cylinder has a volume of 0.49cc (which is

hardly surprising since a 490cc Norton’s

bore and stroke is 79 x 100).

So, for instance, if Bob’s current volume

is 51.52 (working out at 11.7:1) he would

need a 2mm shim to correct it.

I reckon my maths teacher should eat

his cruel words…

86

87


ick’s fixes

Workshop

RICK answers your queries

Studying studs Pt1

Tony Dodsworth in Johannesburg is

building a pre-unit 500cc Triumph

for which he acquired a nice set of

late Speed Twin crankcases, but

there’s a catch: “None of my 500cc

barrels fit them – but 650 barrels do!

Any ideas what’s going on?”

As it happens, Tony, yes. Because

I ran into a similar problem building

my Tribsa scrambler. The answer is

to be found in Harry Woolridge’s

excellent Triumph Speed Twin and

Thunderbird Bible. Prior to 1956,

the barrel stud spacing was different

between 500 and 650 but from then

it was standardised to the 650 pitch

so pre-’56 500 barrels won’t fit.

In my case I had mismatched

cases – one pre-’56, one post – but in

the 30-odd years since I bought

them I only realised when I fitted

cylinder base studs in the empty

holes, having already rebuilt the

bottom end. Luckily I had another

bottom end with the right stud

spacing – but that led to another

problem. Although it appeared to be

the ‘big-bearing’ crankcase I needed,

it turned out to be the big-bearing

casting – but machined for a smallbearing

crank. I managed to

machine it out OK, but it underlined

the fact that although these engines

all look the same, there are

significant changes that need to be

borne in mind.

ABOVE: Barrels

corroded to a

head may require

recourse to a press

LEFT: Late 500cc

Triumph

crankcases share

stud spacings with

the 650, but early

ones do not

Studying studs pt2

Tony Allanson has a particularly

nasty problem to resolve. Corrosion

has stuck his BSA A65 cylinder head

fast onto its studs. After

unsuccessfully trying a spanner on

the crank nut with the combustion

chamber filled with rope (via the

plug hole), he has now removed the

top end as a unit but is unsure where

to go next, heat and penetrating oil

having already failed.

I think the only way to do this is

with a press. The barrel will need to

be supported on flat bars, upside

down. Then I would use two pistondiameter

pieces of aluminium (or

wood) that can be bridged at the

exposed end with a strong plate and

see if the head can be pushed off

that way.

Hopefully, the even pressure

would cause the head to throw in

the towel – but if it’s stubborn,

beware breaking off the cylinder

flange. It may be necessary to have a

thick plate laser cut and drilled to

replicate the crankcase mouth so

that the barrel can be bolted

through all its holes for strength.

Rick’s top tips

Call that sturdy? Lever it out, mate!

I’m not impressed with this new inverted lever, bought by a friend on the

internet. Compared to an original it’s very spindly – little thicker than a

teaspoon handle. You wouldn’t need to be Uri Geller to bend it – as you

might discover under emergency braking...

This is not what I call boxing clever

My mate Bruce showed me a customer’s Monet Goyon gearbox that

jumps out of gear. Despite being a matched pair, the machining was way

out, with the selector shaft misaligned by 5mm! It’s all fixed now, but be

aware – just because it’s original doesn’t necessarily mean it’s correct...

88


ick’s fixes

Taking a peak

Pete Grogan emails from Australia,

asking about the headlight peak

he’s spotted on one of my bikes.

“Was there any benefit in these or

were they just cosmetic? I like the

look and am trying to find one for

my BSA Super Rocket,” he says.

These peaks were an anti-dazzle

accessory, first seen on acetylene

lamps in the vintage era and

re-introduced in the 1950s – despite

the improbability of dazzling

anyone with a 6v 30/24watt

headlight bulb!

Adding a bit of ‘bling’ to the

front end, they regained popularity

during the Rocker era. Very hard to

find by the time I started looking, I

managed to get the odd one here

and there until I had one on every

bike I owned – including a little one

Workshop

on my 98cc Excelsior. My dad

regarded them as bolt-on junk that,

if anything, slowed the bike down

and I eventually gave in and

stopped using them. But finding I

had a couple left recently, I fitted

them for old time’s sake.

These days they are popular

accessories for British classic cars of

the ’50s and ’60s, which also used a

7in headlight, so they fit just the

same. They have a turned-up lip

that clips in between the lamp glass

and the rim, retained by the

headlight W-clips – although the

peak sometimes slips round to a

jaunty angle, so I usually glue them

in place with some silicone sealant.

You can probably find them at

car shows or online, but avoid ones

for VW Beetles – the laid-back

headlight position means the peak

points down when fitted to a bike.

Love them or hate

them, headlight

peaks have been

around a long time

RICK’s final word

Signed and sealed

Bill Hannah writes to suggest I retract my advice

about machining pre-unit Triumph timing covers to

accept an oil feed seal instead of the standard

phosphor bronze bush (Fixes February). He says

although this conversion is alleged to improve oil

pressure, he has seen the seal lip ‘blow out’, resulting

in zero pressure and a wrecked engine. The original

bush, he points out, can wear but cannot fail

completely, adding that if the cover has been cast

off-centre, the hole will ‘daylight’ if machined,

needing an ally-welded repair (see above).

Well, I understand your concern, Bill, but this is

not my experience. I had my first cover converted in

the mid-’80s after finding that new bushes were no

longer available. My casting was off-centre, causing

the circlip groove to break though at one point but it

worked perfectly for years on my Tribsa before

getting ‘borrowed’ for a ’59 Thunderbird. It’s still on

there and I have never even changed the seal since.

In my feature on ‘Rockerbox’ a while ago, I

passed on their warning about cheap pattern seals –

apparently there have been some very flimsy ones on

the market, and suspect these caused Bill’s problem.

Triumph fitted garter seals to all big twins from ’63-

on and I don’t remember hearing of any problems –

even with the 750’s uprated oil pump. The seal

conversion may not be an improvement but it’s an

easy fix and I still can’t see anything wrong with it.

RIDE WITH

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