An article on the 1926 Tourist Trophy Races reads:
Roughly speaking, the standard T.T. Panther will be used in the races, though several small but important alterations have been made. The inlet port is now at right angles to the cylinder bore, and the gudgeon pin is now clamped into the small end of the connecting rod.
The makers have decided that lubrication is the most important item in a T.T. machine, and a special system has been devised. A standard mechanical pump delivers oil under pressure (adjustable) through the crankshaft and flywheels to the crank-pin, which is provided with four holes. These holes allow the oil to penetrate to the big-end rollers, thence to the sprayer into the cylinder bore, and the inside of the piston. Separate feeds are provided for the timing gear and inlet valve guide, the overhead rocker gear being lubricated by oil from the timing case via, the tappet enclosing tube.
The saddle pillar tank is carried as a stand-by should the other system fail and serves to lubricate the chains. A four-speed close ratio box is fitted, the petrol tank holds 3 gallons, and the sump 3 pints of oil. The engine develops 22 h.p., and is capable of 90 m.p.h.
C. T. Ashby, H. M. Walters, and T. F. Bullus, all good men, are the riders.
Extract from a report on the 1926 Olympia Show:
A longer taper to the rear end of the tank, resulting in a greatly improved appearance, will be noticed on the various P. & M. Panther models. Some of these machines are supplied with speed guarantees varying from 75 m.p.h. to 90 m.p.h., and provided that the makers have learnt their lesson from the T.T., an always excellent machine should have advanced one step nearer perfection.
Attractive as the Panther may be, it is probable that it will be somewhat outshone in interest by the new " Cuckoo in the Nest" that has been hatched at Cleckheaton.
Excerpt from Reports on sports machines of 1926 (penned in 1949)
The T.T. P. & M. Panther came up for test next, in 84 by 90 mm., 499cc. form. This engine took the place of the front down tube and had fully automatic sump lubrication. The P. & M. gearbox normally possessed ratios of 8.4, 7.0, 5.4 and 4.5 to 1, but the test machine had a 12 to 1 bottom gear, the saddle tank accommodated 2¼ gallons of petrol and the sump 3½ pints of oil and the Webb forks gave remarkable road-holding and stability at really high speeds. What speed? Alas, no speedometer was fitted, but "Paul Sadler," now doing the tests, estimated it at about 80 m.p.h. Yet there was docility in traffic and enormous acceleration. A faulty decompressor spoilt easy starting and an odd engine vibration intruded when "all-out." The gear-change needed practice, but was snappy and the brakes were "exceptionally good" (by 1926 standards, of course), although the r.h. pedal could easily be mistaken for the decompressor.
A sporting small car good for some 70 m.p.h. was easily disposed of by very moderate throttle in the P. & M.'s top gear; 50/50 mixture was used and an oiled plug experienced because there had been too much u.c. lubricant in the tank. At about 50 m.p.h. the machine became happy in top gear and was really sweet at about 65, keeping that up all day with no sign of overheating, causing the photographer's 3 h.p. twin to eat its tappet rods and lose an exhaust pipe and still fail to keep anywhere near the "Panther."
Snags? Well, a spanner was needed to undo the oil filler and the magneto was very far advanced. Otherwise, full marks, notably to the good finish. The price in 1926 was £85, or £92 10s. with a Brooklands' Certificate for 85 m.p.h.
