The beginnings of a wonderful relationship

Part two

The early years of Bob McIntyre with Joe Potts

In erratum

Before we get too far into this article we feel that we should point out a couple of clarifications from the first part of the story, printed in the previous issue. Firstly, the majority of images in the feature were from the Joe Potts archive (and this wonderful outlet continues to provide the majority of the images for this episode too) and secondly, the image of Bob Mac on page 56 of the first article should have been this image (right) of Bob on the Junior machine at the 1955TT. Apologies all round Now, on with the Bob Mac/Joe Potts story...

Sowhy would Bob turn down these works rides and instead decide to stay with Joe, working at the back of a funeral parlour in Bellshill, Glasgow?The answer: Bobwasaman of his word and he had made plans with Joe for the 1956 season. Bob’s friendshipwith Potts and his belief in what they could achieve together meant that he would continuewith these plans.

During the 1955 season it was apparent that the Joe Potts/Bob McIntyre team was the only privateer able to compete with the Works teams. With the reputation gained by both in 1955, Joewas able to start getting lots of spares out of the ‘back door’ of Norton’s. This included unmachined cylinder heads, crankcases, pistons etc. Joe had effectively taken off and moved on fromwhere the Works team had been operating. Norton recognised this and as well as providing the aforementioned parts, it was also supplying drawings of parts and engines from theWorks team. With the unmachined crankcases Joewould nowbe able to start creating the highly developed special Potts engines that were stamped with JP engine numbers. Huge amounts of sponsorship money started flooding in to the team, the largest portion coming from Shell.

So what were the new plans between Bob and Joe? It was Potts Manx machines, but most interestingly is that there would be an additional machine to the stable; the Potts 250cc. The Potts 250 started life as a short-stroke 350cc Manx crankcase, cambox, barrel and unmachined cylinder head. One interesting aspect of the Potts 250 is that it was based on a drawing provided to Joe by Norton, of a similar engine to the one Joe Craig had envisaged. The bore and stroke dimensions for the Potts 250 was chosen to be 70mm by 64mm. The new crankshaft assembly was machined in the workshop at North Road to allow for the reduction in engine stroke. The new crank was a one-piece unit that was fitted with an outside flywheel to allow the use of an ultra short connecting rod. The connecting rod wasmachined by Joe and wasmade from aluminium and it featured a split