Saturday, March 21, 2009

Norton Model 7 Restoration Part 1: Postmortem

The machine was long dead when I rolled it off the delivery truck and into a cold Seattle rain. I pushed it across the broken street to the workshop space I rent, and, as it sat dripping, I went over it assessing what I had just gotten myself into.
It was a 1950 Norton Model 7, a specimen of the first multi-cylinder engine Norton had ever produced. (A Peugeot engine had propelled the Norton twin that won its class in the inaugural Isle of Man TT in 1907.) Although it was not strictly a sporting motorcycle, Norton advertising of the period made all the hay it could of the firm’s myriad racing successes, and so Nortons gave their new twin the name “Dominator.” The model debuted at the 1948 Earl’s Court show, and production commenced for the 1949 model year.
The Norton Owners Club in England reviewed its copy of the factory records and told me that this particular machine was dispatched from the Bracebridge Street works in Birmingham on March 20, 1950. It and two consecutive Model 7s had been purchased by Brockhouse Limited and were destined for the United States. Brockhouse had purchased Indian Moto Cycles in the late 1940s and by 1950 was actively using the Indian dealership network in America to sell various British bikes. Norton ads in American motorcycle magazines proclaimed “Sold by Indian.”
The seller in Cincinnati had told me the bike was last licensed in 1974 in Minnesota, Land of 10,000 Lakes. But as I looked over the bike in 1998, it was another 24 years on; by now the bike had been off the road for as long as it had been on it.
By all appearances this was a machine that had suffered from what I call “Volkswagen Syndrome”—a sad mechanical fate that befalls obsolete vehicles that refuse to die. They are hardly worth repairing, and they certainly are not worth maintaining, but they soldier on with everything about to give up the ghost, yet not enough things do. Whatever the aesthetic reality, cases of Volkswagen Syndrome are often interesting if only for their extraordinarily bodged repairs and extremely worn parts.
Most of the bike was there, but it was in generally shabby condition. The gas tank and fenders were in gray primer, which told me they weren’t good enough to tolerate either bare or painted. Sheet metal parts were dented, fatigue cracked, and repaired badly. Short strands of wire stuck out of the few electrical components on board; someone had re-wired the plot completely with brown wire only to have someone else come along and snip off all of it. The drive chain was one size too wide and had carved a path out of the back of the primary-chain cover. The sprocket teeth were worn hook shaped. Happily the frame and engine numbers did indeed match, just as I had been told. But when I removed the gas tank it was obvious that the frame was bent at the head tube.
The original owner must have lost the tool kit on his way out of the Indian dealership. Water-pump pliers and pipe wrenches had chewed up bolt heads, nuts, and even the carburetor. Some bolts had been removed from non-critical areas to serve where the original fasteners had left the scene. Unable to remove the fork-top bolts, someone had drilled them, tapped them, and installed a bolt in one and a stud and nut in the other so that fork oil could be added without having to borrow a really big wrench.
In the tradition of those before me, I tried to piece the Dominator together enough to get it running. I would restore it as I rode it. The problem was, everything I touched came apart in my hands. I finally gave up and tore it down for a complete rebuild.
The machine had apparently been driven two-up for a fair distance. Once the primer was stripped from the rear fender, it was obvious that a pillion saddle had been bolted on and used long enough to severely fatigue and tear the top of the fender. One of the original Norton pillion footrests was received with the bike, but the other was a well-worn replacement. Disassembling the plunger-sprung rear suspension revealed that one of the coil springs was broken. Its two broken halves had wound past each other to form one very short, incompressible spring.
From the bent frame and fork yokes it was obvious that the bike had been crashed. At the moment of impact, the forks sprung back so far that the front fender got caved in from behind when it smacked into the frame tube. The steering had then whipped right hard enough to strike a sharp dent in the front of the bulbous, chrome, gas tank. Twenty-two smaller dents balanced out the tank damage. The 21-inch front wheel, when rolled across the shop floor, wobbled badly over its repaired spots and fell immediately upon reaching a grizzly warp that was probably the collision site. Regardless of the damage, someone had continued to ride the bike after rounding out the front rim as best they could and straightening the dent in the back of the fender. It was an old repair—they had used lead instead of Bondo on the fender.
Unscrewing the timing cover revealed that the phenolic generator-drive gear was missing. But even disconnected, the generator would not turn. It turned out that a commutator segment had escaped from the spinning armature, snagged the brushes, twisted the brush holders, and stopped the generator cold. This might have been enough to destroy the fiber drive gear, but inside the engine there wasn’t even the tiniest trace of phenolic shrapnel. Someone had already cleaned out the remains and put the bike back into operation without any electrics except the magneto. That explained the snipped-off wiring.
When splitting the crankcases I discovered that the best secrets were those hidden deepest. The left crankcase bore evidence of having been pierced by a broken connecting rod. The hole had been expertly welded shut, but the welder had also addressed the left piston, welding in place the broken pieces of piston skirt that had been cleaved off by the flailing remains of the broken con rod. The welds had been crudely ground off and the piston re-installed in its bore, connected to a replacement rod that was obviously a different casting from its neighbor to the right. The right con rod had suffered a giant gouge from the event but was retained. And this despite the fact that Norton twins use aluminum rods, so re-use was tantamount to a postponed death sentence.
The big-end shell bearings had also been re-used, and, when one had checked out lose, a piece of paper had been stuck behind the bearing to take up the slack. Because the paper used was a piece of blank shop receipt, I assumed the whole mess was a professional job. By the time the rod failed, the bike had already lived a long life; the pistons that they repaired and reused were 0.020” oversize.
In the end, the most surprising thing I found was the absence of any obvious cause of death, except perhaps for an indifferent magneto. Despite the laundry list of ailments, it looked like it might have continued to limp along had someone not started to disassemble it to paint a few parts.
Even so, it is all better now, and I am happy to say it is mostly an amateur job. In late September 2001, the engine fired for the first time in a long time, and by May 2002 I had the machine assembled, wired, and on the road. Since then it has covered more than 10,000 miles from sea level to 7,000 feet. Its greatest feat was a 1,200-mile trip from Seattle to the International Norton Owners Association (INOA) rally in southwest Oregon in 2005. My brother (1939 Ariel Red Hunter!) and I rode there down the Pacific Coast Highway and rode back along the Cascade Mountains. The Model 7 Dominator is such a wonderful machine to ride that I can see why prior owners had tried to keep it on the road despite its various incidents and the mounting toll of bodged repairs.

1 comment:

  1. Prepareing to frame up rebuild a 1950 md7 and found this article very interesting and informative. Enjoyed all the articles. Thanks for the great article, and site.
    RS from KS.