PAN­THER MODEL 100

Rowena Hosea­son’s purrsuit of purr­fec­tion takes her to Cleck­heaton, the home of bad jokes about big pussy­cats…

Real Classic - - Contents - Pho­tos by Rick at Fo­cused Im­age En­ter­prises

Rowena Hosea­son’s purrsuit of purr­fec­tion takes her to Cleck­heaton, the home of bad jokes about big pussy­cats…

In 1911, Ph­elon & Moore claimed to have created ‘the per­fected mo­tor­cy­cle’, ad­ver­tis­ing hype which might, with hind­sight, have been just a tiny bit pre­ma­ture. Half a cen­tury later, it must’ve been easy for the fast lads of the 1960s, sit­ting astride their Bon­nevilles and Gold Stars and Dom­i­na­tors, to scoff at the slow-revving heavy­weight sin­gles. As our own Ed­i­tor once said, ‘they are un­de­ni­ably prim­i­tive, even by the stan­dards of the day.’

But – like Vin­cent, Dou­glas and Ve­lo­cette – P&M did things in their own inim­itable way, ex­per­i­ment­ing with in­no­va­tive en­gi­neer­ing which the mass market man­u­fac­tur­ers sim­ply wouldn’t risk. So per­haps we can (with not in­con­sid­er­able kind­ness) con­sider P&M’s state­ment to be an am­bi­tion; an ad­mirable in­ten­tion to achieve ex­cel­lence in an in­dus­try where the pa­ram­e­ters are per­ma­nently de­vel­op­ing.

In­deed, in the years im­me­di­ately af­ter WW2, the big Pan­thers ap­peared to be on a par with their high-ca­pac­ity sin­gle-cylin­der op­po­si­tion. Or, as P&M put it in 1948, the Model 100 was ‘the finest ma­chine in its class. De­vel­oped over a longer pe­riod than any other mo­tor­cy­cle, the 600cc Pan­ther is now per­fected in ev­ery de­tail and will re­main in pro­duc­tion in­def­i­nitely.

‘Ask the man who owns one,’ said P&M’s ad­vert. So we did…

‘Af­ter fin­ish­ing my ap­pren­tice­ship in 1994, I took off to go trav­el­ling,’ says Dan, owner of the 1950 Model 100 you see here, who lives in Aus­tralia.

‘Much of my fam­ily is orig­i­nally from York­shire, the home of Ph­elon & Moore. I first spot­ted a few Pan­thers in Har­ro­gate on a rare sunny day and read a bit about thhem. I learned that they were mmade be­tween 1900 and 1967 in Cleck­heaton, where my m great-grand­fa­ther had an e ngi­neer­ing fac­tory.

‘I was im­me­di­ately cu­ri­ous and read lots more about them – start­ing with “The Pan­ther Story” by Barry M Jones, an amaz­ing, in-depth book. It ex­plains how the Model 100 was launched in 1932 and con­tin­ued through to 1963. While the en­gine and over­all lay­out stayed the same, an ohv sloper en­gine in a frame where the en­gine re­places the front down­tube, the spec­i­fi­ca­tions steadily evolved over 30 years.’

The Model 100 resur­faced af­ter WW2 in 1946 with hot­ter tim­ing and a twin­port head, Webb-type girder forks and a rigid rear end. ‘ They were a work­ing class, util­i­tar­ian bike, fa­mous for pulling around a fam­ily in a side­car or be­ing loaded up with a side­car for trades­men. Peo­ple who own Pan­thers love them.’

Dowty air forks ar­rived for 1947, then were re­placed by Pan­ther’s own type of tele­scop­ics in 1954, which was the same year that swing­ing arm rear sus­pen­sion ar­rived. The

23bhp Model 100 adopted a sin­gle-port head in 1957, and the 28bhp Model 120 joined it in 1959, gain­ing 50cc by ex­tend­ing the al­ready long-stroke cylin­der to 106mm. In deluxe form from 1957, the Model 120 weighed a sub­stan­tial 425lb, a whop­ping 40lb more than the rigid Model 100.

In fact, the Model 100 is usu­ally viewed as be­ing nicer to live with than the later 650. It’s not got quite so much grunt as the Model 120 but is less prone to oil­ing is­sues. The 650 stayed in pro­duc­tion un­til 1966, three years af­ter the 600 had been dis­con­tin­ued.

Four decades later, Dan wanted to re­in­force his con­nec­tion with his fam­ily’s an­ces­tral home­land. ‘I worked all over the world as a ma­rine en­gi­neer for years and moved back to Aus­tralia in 2007. All that time I’d been look­ing for a suit­able Pan­ther – I’ve al­ways had a pref­er­ence for sin­gle cylin­der mo­tor­cy­cles; I rode ju­nior speed­way and then crashed a lot in se­niors on 500cc so­los.

‘A friend fi­nally spot­ted one that had been re­built by a fella named Shaun, lo­cated near Perth. The Model 100 was one of many that Shaun pur­chased in a bulk load from a farm. The pre­vi­ous owner had at one stage been South Aus­tralia’s Pan­ther dealer. The Pan­ther was in poor con­di­tion when Shaun found her but was the ex­act rigid type I wanted.

‘Shaun res­ur­rected the Model 100 so it was 95% fin­ished, and I wrapped up the last few cos­metic items, then sorted the nig­gles to make it a re­li­able run­ner. My Pan­ther was fi­nally reg­is­tered in 2015. The bike’s been af­fec­tion­ately nick­named “June” af­ter my great-aunt from York­shire.

‘I’ve rid­den the Model 100 on bike events that I or­gan­ise or take part in, like the Dis­tin­guished Gen­tle­man’s Ride and ‘Cruise for the Cause’, plus a lot of lo­cal Mo­tor Ve­hi­cle En­thu­si­ast Club rides. I also took her down to a Pan­ther Rally in South Aus­tralia where I meet up with a load of Aus­tralian Pan­ther

Reg­is­ter mem­bers.

‘Rid­ing bikes built from 1914 through to 1967, we blasted around a sen­sa­tional route through the hills. June loved the cooler air – al­though she rides sweetly, I don’t push her too hard here in Dar­win due to the higher am­bi­ent air tem­per­a­tures. I pre­fer to sit at 55mph when go­ing down the high­way.’

The lo­cal cli­mate in Dan’s neck of the woods – around 30°C for most of the year – has some other ef­fects. ‘I run my tyres at 34 to 36psi. The ride is fine and the com­bi­na­tion of the tar­mac tem­per­a­ture and mod­ern tyre car­cass con­struc­tion means the tyres wear less at these pres­sures. I’ve re­moved the choke slide as there’s no need for it in my part of the world. And I had to play about with the carb to get the nee­dle height right for lo­cal am­bi­ent tem­per­a­tures.’

Dan isn’t the only owner who needed to spend some time set­ting up his Pan­ther’s car­bu­re­tion. Mod­ern con­cen­tric-type

Am al Pre­miers can be ad­justed to suit the big ss­in­gles, but each ma­chine seems to need in­di­vid dual set­ting up, with much trial and er­ror re­quired to get the jet­ting cor­rect. Err on the side of run­ning richh, say the gu­rus. You def­i­nitely know when you’ve got it righht – a heavy­weight Pan­ther is all about that lon­g­long-stroke lope.lope

‘June loves pulling up hills, with loads of torque like the de­sign­ers in­tended for haul­ing side­cars. She sounds sweet, and I love the sound of a large sin­gle. They are fa­mous for one thump be­tween lamp posts. Idling on the stand, if you re­tard the tim­ing they can rev ex­tremely slow.

‘ There is a knack to start­ing these ma­chines. You need to use the de­com­pres­sion lever on the crank­case right side, by lift­ing it up­ward. Tickle the carb til it oozes, re­tard the tim­ing by the lever on the han­dle­bars. I roll it over us­ing the han­dle­bar valve-lifter as I have a weak an­kle, then I drop the valve lifter and she will start on the kick-through.’

Pan­thers do have some­thing of a fear­some rep­u­ta­tion when it comes to kick­start­ing, which has even been utilised as a sub­tle form of anti-theft se­cu­rity. Sim­ply leave the ig­ni­tion set to full ad­vance, and any light-fin­gered fiend will get the re­ward they so justly de­serve! Al­ter­na­tively, use a stout se­cu­rity chain and fit elec­tronic ig­ni­tion to ease the start­ing process. Boyer’s ig­ni­tion sys­tem can be adapted to suit the heavy­weights, with a coil, and it cures the big cat’s habit of kick­ing back. On the down­side, it de­mands a sig­nif­i­cant

cur­rent, so you’ll need a posh mod­ern bat­tery which holds its Volts.

If you’re kick­ing the tyres of a prospec­tive Pan­ther pur­chase, then you’ll def­i­nitely want to check its re­cent his­tory. Has the gear­ing been set for a solo (26-tooth) or side­car (24-tooth)? On side­car tugs, you may find that a sin­gle-port cylin­der head has been fit­ted with just one ex­haust pipe on the right, leav­ing space for the chair on the left. A test ride is es­sen­tial to be sure that a solo ma­chine still steers straight; frames do twist af­ter decades of haul­ing the whole fam­ily on holiday. P&M’s unique frame de­sign can spring apart af­ter all that abuse: it’s an easy fix us­ing an hy­draulic jack to rese­cure the frame to the en­gine, so ask th he seller if this has been done.

The Pan­ther’s Bur­man BA gear­box is di if­fer­ent to most four-speed­ers used by po ost-war Bri­tish bikes; only the Vin­cent Co omet was fit­ted with this ‘top piv­ot­ing’ ty ype. So don’t ex­pect spares from AMC,

A riel or Ve­lo­cette gear­boxes to be suit­able. Te eeth on the Pan­ther’s kick­start quad­rants ca an wear, so turn the en­gine over gen­tly a nd ‘feel’ for any slop or snatch­ing when the m mech­a­nism meets re­sis­tance.

Splines on the clutch cen­tre can suf­fer fr rom the en­gine’s thump­ing torque d eliv­ery, and the five-spring, three-plate clutch c can be tricky to assem­ble just right. There’s a tried-and trusted clutch fix rec­om­mended by the POC, so check any re­build records to see if it’s al­ready been done. Gear­box ad­just­ment bolts are prone to strip­ping, and the ex­haust port threads can cor­rode and then strip, mak­ing it tricky to se­cure the down­pipes. Re­place­ment cylin­der heads are scarce, but the club has sev­eral sug­ges­tions for re­claim­ing the thread, and even a Kawasaki part num­ber for a suit­able copper seal!

Don’t be sur­prised if there’s gen­tle oil weeps from the usual places like the pushrod tube, cylin­der base and pri­mary chain­case – get the en­gine good and hot to make sure you haven’t got a gusher. Heavy­weight Pan­thers tend to con­sume co­pi­ous quan­ti­ties of lu­bri­cant at the best of times – a pint per hun­dred miles, even! – so check and re­plen­ish reg­u­larly on any long rides. One cause could be the slope of the en­gine and a slightly worn ex­haust valve stem, but there are sev­eral the­o­ries on the

sub­ject and sev­eral sug­gested so­lu­tions.

An­other is­sue al­lied to oil con­sump­tion is how fast the big cat can con­sume its own spark plugs; a colder / harder plug can help if your en­gine is run­ning hot.

If you get a de­cent test ride on a warm day, ob­serve how hot the top end is get­ting – it has been known for the cast-iron cylin­der head fins to cor­rode over time, grad­u­ally de­grad­ing and los­ing sur­face area. Top end over­heat­ing then man­i­fests it­self as the kind of in­ter­mit­tent fault most

typ­i­cally blamed on electrics or fu­elling. The fix is to re­place the head with one in bet­ter con­di­tion (the POC re­man­u­fac­tured heads in re­cent years), or have the fins builtup by a metal spe­cial­ist. Not that Dan has ex­pe­ri­enced prob­lems of this type…

‘Dur­ing the 3500 miles we’ve cov­ered, I had to re­build the Bur­man four-speed gear­box, due to a clutch nut com­ing loose. It could do with an­other re­build now, though I’m used to its foibles.’ The POC can sup­ply an oil seal for the main­shaft to swap from grease in the gear­box to EP90. That might be ad­vis­able for peo­ple in colder cli­mates, but we sus­pect that in Aus­tralia Dan is prob­a­bly bet­ter off stick­ing with grease as orig­i­nally spec­i­fied. Espe­cially as he’s not averse to clock­ing up the miles aboard his Model 100.

‘I’ve rid­den as much as 300 miles in a day,’ says Dan, ‘and never found her un­com­fort­able.’ He reck­ons that’s down to the sprung sad­dle, but the fact he’s ‘only’ 45 years old prob­a­bly helps! As with many Pan­thers that came with Dowty’s air forks, Dan’s front end has been fit­ted with in­ter­nal springs, and this def­i­nitely en­hances longdis­tance com­fort.

If you do con­sider buy­ing a Pan­ther with its orig­i­nal Oleo­matic forks in­tact, then be pre­pared to check and fet­tle them to avoid air seep­ing from the seals. In­deed, given the age of the metal sur­faces it may not be pos­si­ble to get a good enough seal to main­tain the nec­es­sary pres­sure – so your front end could sag un­ex­pect­edly…

All of which is a far cry from when the air forks were in­tro­duced shortly af­ter WW2. Part of P&M’s con­tin­ual pur­suit of per­fec­tion, the Dowty fork of­fered ‘a vastly su­pe­rior ride to me­chan­i­cal spring sys­tems. The ad­di­tional forks added only about £10 to the model prices and this was money well spent,’ ac­cord­ing to au­thor Barry M Jones. ‘Rap­tur­ous ap­plause for the new forks en­sured that once again P&M was lead­ing the field.’

The Model 100 may feel wieldy due to its low-slung sad­dle and lack of rear sus­pen­sion, but it still tips the scales at 385lb dry, and that mass has to be hauled to a halt by a half-width 7” brake on the 19” front wheel. There’s an 8” drum on the En­field hub at the back, but even so Dan says he ‘an­tic­i­pates in­ter­sec­tions well in ad­vance!’ He also ad­mits that the Pan­ther’s light­ing isn’t the best. ‘I’m still run­ning the orig­i­nal Lu­cas 6V set-up. If it was good enough for the 1950s then it’s good enough for me!’

‘I’ve got to know Pan­thers quite well, aided in par­tic­u­lar by Lau­rence Neal’s in-depth and il­lus­trated books, one about Pan­ther en­gines and gear­boxes, the other on heavy­weight cy­cle parts. I’ve rarely seen such thor­oughly de­tailed pub­li­ca­tions on any other mo­tor­cy­cle mar­que. The Pan­ther Own­ers’ Club has an ex­ten­sive li­brary and a second-to-none spares scheme. The club mem­bers have ex­ten­sive knowl­edge and spares which are keenly shared, and the monthly ‘Sloper’ mag­a­zine is ex­cep­tional.

‘I now own four Pan­thers; three other projects in progress. A 1938 Model 85 twin-port high-pipe 350; a very in­tact and orig­i­nal 1938 Model 30, which was the cheap­est bike you could buy in the UK in its day at £27, and a 1931 Model 95 500cc Deluxe. I in­tend to re­store them all to as close to orig­i­nal con­di­tion as pos­si­ble – and then ride them as much as pos­si­ble. My work­shop is the old Qan­tas hangar in Dar­win, orig­i­nally built in 1934 as the first Aus­tralian in­ter­na­tional air­port!

‘Pan­thers are great bikes. They turn heads and are a lot of fun to ride, and the ex­pe­ri­ence is en­hanced by be­ing part of the great, global com­mu­nity of Pan­ther own­ers. Just don’t ex­pect it to set any world-speed records!

‘ They’re easy rid­ing, solid and re­li­able: very com­fort­able at 55mph. Throt­tle re­sponse is good, she has a lot of torque, and is easy enough to move around at slow speeds – she isn’t so heavy.’

So then, let’s re­turn to our orig­i­nal ques­tion. P&M reck­oned the Model 100 was the finest ma­chine in its class – just ask an owner. Here’s one now. ‘It’s def­i­nitely Cleck­heaton’s finest en­gi­neer­ing,’ con­firms Dan. ‘No im­prove­ments re­quired.’

If not quite the per­fected mo­tor­cy­cle, then cer­tainly a per­fect Pan­ther.

P&M reck­oned the Model 100 was ‘the great­est of them all. When rid­den solo its per­for­mance is amaz­ing. Quiet, ef­fort­less and un­tir­ing, it cov­ers the miles with­out the least fuss or bother…’

weir

Pri­mary drive is via a chain to a Bur­man clutch, and keep­ing both of them lubed is a good idea. The en­gine’s top end is held to its bot­tom end by a pair of mon­ster U-bolts, which is a neat ar­range­ment to pre­vent them pulling out of the al­loy crankcases when tight­ened with vigour

A se­ri­ously sin­gu­lar en­gine

The Model 100’s oil lives in the ribbed wedge at the front of the crankcases, nes­tled be­tween the down­pipes and kept sep­a­rate from the en­gine’s in­nards by a

In solo trim a Model 100 could eas­ily re­turn 80mpg while 60mpg proved pos­si­ble even when pulling a side­car. Fuel econ­omy was aided by the small­bore ‘up-draught’ carb

The Bur­man gear­box is a tough de­vice – and it needs to be.It’sane­spe­cial­ly­good idea to keep it filled to the right lev­el­with lube–and to check with the POC which lubeis­the best

Front forks are Oleo­mat­ics by Dowty, but these springs now use steel coils rather than the bouncy power of fresh air. Al­though the forks ap­pear to be of a lead­ing axle de­sign, in fact the legs are re­versible, pro­vid­ing a trail­ing axle al­ter­na­tive, should you fancy that…

The mighty en­gine hangs from the frame by the sub­stan­tial brack­ets hold­ing the rocker box. The carb is ac­tu­ally up-draught, which made a change, while Mr Lu­cas pro­vided all things elec­tri­cal via his well-known mag­dyno de­vice, drive to which was through a sub­stan­tial cou­pling rather than di­rect from the tim­ing gears

Hefty cast-iron fly­wheels con­trib­ute 14lb to the ma­chine’s mass but smooth out low-rev power de­liv­ery, ac­cen­tu­at­ing the Pan­ther’s lazy gait

Al­though mighty in ev­ery sense, Pan­ther’s Model 100 is not in fact mas­sive. It’s as slim as other sin­gles of its era. And it has twin ex­hausts, too

The view from above is sur­pris­ingly con­ven­tional, for such an un­con­ven­tional ma­chine, and the in­stru­men­ta­tion is hardly tax­ing

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