PANTHER MODEL 100
Rowena Hoseason’s purrsuit of purrfection takes her to Cleckheaton, the home of bad jokes about big pussycats…
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
‘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…’
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