See also Panther.
Panther Model 120 was a British motorcycle made between 1965 and 1971 by Phelon & Moore.
An enlarged Panther M100, the 120 had a reputation for being less reliable with a tendency for rapid clutch wear, problematical roller bearings and heavy oil consumption. As competitors produced modern designs, Panther ran into trouble obtaining supplies of Burman gearboxes and Lucas Magdynos, so production ceased in 1966 and the company was wound up.
The Panther sloper engine designed by Granville Bradshaw remained unchanged for 25 years and the 650cc 'heavyweight' had many of the Model 100 components. The increased capacity was achieved by boring out the Model 100 cylinder by 1mm and increasing the stroke by 6mm. As well as increased low speed torque this improved acceleration and top end cruising speed.
This put additional strain on the main bearings and crankcases, leading to reliability problems. The 120 also suffered with lubrication problems from the large sump cast into the front of the engine. Oil was pumped to the top of the sloper engine but return was erratic and oil consumption very heavy. The main shaft was redesigned with larger ball journal main bearings, A smaller exhaust valve combined with a larger Amal monobloc carburettor gave the Model 120 28 bhp at 4500 rpm, an increase of 4 bhp over the Model 100.
Motorcycle sidecars were popular at the end of the 1950's, so the Model 120 was provided with a purpose built sidecar chassis, connected by a three point mounting which provided minimal alignment problems. The sidecar wheel was interchangeable with the motorcycle wheels and had swinging arm suspension with an Armstrong shock absorber. A trailer with a towbar was also provided as an option.
By 1962 Phelon & Moore were in financial trouble and went into receivership. The Model 120 stayed in production for as long as the supply of spare parts lasted, but they finally ran out in 1966 and the company folded. It wasn't quite the end for the big Panther, however, as they were cheap and economical and continued to sell for another year after production ended.