Panther Lore

Oil Consumption
The Panther Bites Back
Clutch Centres
Dowty Forks

Probably the biggest and longest running debate on Panthers is "why do they consume so much oil?" Figures of 1 pint per hundred miles for the heavyweights are oft mentioned. Pre-war machines are best (lowest consumption) whilst the Model 120 is the thirstiest. Many reasons are put forward as are potential fixes. IMHO the slope of the engine resulting in the exhaust valve stem and guide sitting in a puddle of oil sounds like a pretty viable cause - a slightly loose fit of stem in guide resulting in oil being drawn through and blown out of the exhaust - good for exhaust pipe life, bad for emissions and oil consumption!

Then again another view, from Rollo Turner, is:

On the never ending saga of oil consumption I am pretty sure that the majority of oil goes up past the rings not down the exhaust guide. If it did every Panther would be followed around by the most colossal plume of blue smoke and surprisingly some of the heaviest oil consuming beasts blow little smoke. The reason for this is that when it comes up past the rings it tends to burn more and therefore smoke less. Why this should be so is one of lifes great mysteries. I am now working on two theories. The first is that God never did like Panthers and has visited upon this one make all the oil consumption problems from all British bikes ever. The other is that the breathing arrangement is poor. The trouble is I have not yet come up with a fix!!

And Jordan Princic offers the view:

Theoretically, there is no reason why Panthers should use oil more than other similar designs. It is not likely to be because of its sloping cylinder, as there are v-format engines that also slope with no problem. Inundation of the exhaust guide with oil shouldn't account for much, as, unlike the inlet, it is subject to pressure rather than vacuum, which pressure would tend to keep oil out, not in. I tend to think it is an excess of oil in the flywheel compartment that gets thrown up the bore and then gets past the rings and is lost. Why are some engines worse than others? Dunno but it might be that the lip that scrapes the oil off the flywheels is farther away from the flywheels' rims in some cases. Note that 650s, that have the worst reputation for oil consumption, are 1/8 inch smaller in flywheel diameter than the 600s. Maybe some experimentation with an extended lip modification could be tried by some enterprising person. I haven't had the problem so can't advise how to do this.

This would be in agreement with an article in sloper several years ago by Will Pyke where, I think he extended the scraper and reduced oil consumption as well as increasing performance due to reduced drag on the flywheels.

Then again Bob McGrath offers the following experience:

Can't resist having my two pennorth on Panther oil consumption. Many years ago I rode an early 50's Panther outfit home from Morwell to Mt Beauty for my 21st birthday. (Definitely years ago). On arrival it had very little compression and was not a happy outfit. Nevertheless I had to get back to work and had no alternative but to ride it back again.It took me a full day to ride back to Melbourne as at any speed over about 25mph it threw an oil smoke screen of Royal Navy proportions. I tried cruising at then highway speed between Wangaratta and Benalla and near emptied the sump so had to ride slowly. The next day compression was so low I could only get it started with a tow from a car. On pulling it down when I finally got back to Morwell I found part of the ring lands on the piston missing but the rings hadn't broken. The curious thing was that the missing part of the ring lands were at the rear of the cylinder and precisely in line with the hole for the cylinder oil line feed so that instead of giving the piston additional lubrication the oil line was pumping the oil directly up this little slot into the combustion chamber and out the exhaust. Since then I have always held the opinion that extra oil feeds such as this are fine when the engine is in perfect condition but otherwise increase oil consumption as they force oil past the rings. In effect they create an otherwise non-existent weakness.
 

Check out the Technical Tips page for discussion of possible technical solutions to this problem.

Panthers have a reputation for biting their owners, almost exclusively in the achilles tendon and/or ankle. I read a report of this injury once every year or so. The manual advance/retard (specifically on the heavyweights) should be set for full retard when kickstarting otherwise when the engine fires the kickstart can kick back so hard as to tear the achilles tendon or break the ankle of the rider. Some people say they always leave the bike on full advance to wreak retribution on would be theives! (Not that I am recommending this, it is probably illegal deliberately to do such and there is always the risk you place yourself in!)

According to Barry Jones the techniques for painless starting is simple:

A gentle easing over top dead centre to find compression, engaging the half compression lever on the sump, fully retard and a steady swinging of the foot start lever down (NOT kicking). The engine will start first time.

See also technical tips on starting.

The most common failure that one hears of is that of clutch centre failure on the heavyweights. The significant and uneven power of a 600cc single is delivered to the gearbox through a small clutch centre with a small collection of matchstick sized splines. If planning to circumnavigate the planet on a big Panther a couple of spare clutch centres would be advisable. The Model 120s suffer worst. The cause is usually poor maintenance. On the Technical Page there is substantial correspondence regarding possible solutions to the Clutch Centre Problem.

Postwar models (both lightweight and heavyweight) were fitted with Dowty Oleomatic telescopic forks for several years until Panther developed their own design. These forks were developed from wartime aircraft undercarriage design and are remarkable; they are air sprung and oil damped. In good condition they are excellent. However after fifty years they tend to deflate especially on rough roads! There are several designs for converting to use springs at the sacrifice of the damping. However, this should really be a last resort as, surprisingly, all parts required for renovation are readily available, albeit a little difficult to track down. If they can be rebuilt as air sprung then do it, they are excellent forks.