1928 Norton CS1

Andy Marks
3 days ago
6 min read

Updated: 11 minutes ago

My 1928 Norton CS1 had been off the road since the mid-1980s when I bought it in August 2017. Although it was remarkably complete, it needed a thorough mechanical recommissioning before it could be ridden again. After a brief history of this rare early overhead-cam Norton, this page follows the work I carried out to return it to the road while preserving its original paint, patina and nearly 90 years of history.

A Brief History of the Norton CS1

The CS1 (Camshaft Senior 1) was Norton’s very first overhead cam engine. Introduced in time for the TT in 1927, it went on sale to the public later that year as a race replica. It continued in this guise, alongside the 350cc CJ1 (Camshaft Junior 1), for just a couple of years before its designer, Walter Moore, left Norton for NSU in 1929.

After Moore's departure, Norton brought in Arthur Carroll and the OHC Norton range underwent a complete redesign. Production of the Moore designed CS1, commonly known as the 'Cricket Bat' because of the distinctive shape of the timing chest, lasted less than two years, making surviving examples both rare and highly desirable amongst vintage Norton enthusiasts.

My CS1

I bought my 1928 CS1 in 2017 from a friend who had owned it since 1982. This beauty had been used by the previous owner for a couple of years before being taken off the road because it needed a few jobs done. Life got in the way and, 30+ years later, he decided it was too far down his list to ever get finished.

Apart from the alloy mudguards it is incredibly original. The AMAL carb is a couple of years too new but I decided I could run it on that whilst I kept an eye out for the correct two-jet Binks. If anyone knows where one is available, please let me know! Within a couple of hours of getting it home, my Dad and I had propped it up on the bench as in the above pictures and I had decided to recommission rather than restore it, keeping as much of the patina as possible.

Strip and Clean

The first job was to completely strip and clean the bike. This proved to be very time-consuming, especially as I wanted to preserve the original paint. It had decades worth of grot and grime on it which I had to wash off while being careful not to damage the paint underneath.

Here’s the frame outside our workshop after a lot of cleaning. First, I used a hoover to get all the loose sawdust off, then a hose to blast the worst of the dirt away before finishing off with a can of degreaser and a rag. Once it was clean I touched in the paint to stop rust from taking hold. Over a couple of weeks I repeated this process on every individual part.

Note the three-stay frame, which was only used on the CS1 and ES2 for a couple of years. Quite a rarity now!

Crankcases

I washed the crankcases off in petrol, and blew the oilways through with an airline. They were clean, but it’s always worth checking. Fortunately, this engine was very clean inside. If it had been run on Castrol R in the past, this job could have been a nightmare!

The main bearings were good. Based on the bike's history, I suspect they were new. After cleaning the gasket faces, I was ready to reassemble the bottom end. I packed the bearings with Graphogen to ensure they were well lubricated during the first start-up, until the engine oil had circulated fully. The Graphogen is then flushed out with the first oil change.

Bottom End Reassembly

I reassembled the crankcases and checked for end float. This should be zero on a CS1, as any end float will cause problems with the meshing of the bevel gears.

The bevel gears were in good order so I was able to reassemble them and check for backlash. Again, this was found to be correct. Whoever last put this engine together knew what they were doing.

This engine dates from the early days of dry-sump, recirculating lubrication, and its plunger oil pump is so simple that it seems remarkable it can provide adequate circulation.

I simply had to strip the bottom end of the engine for peace of mind, but it went back together with nothing more than a clean-up.

Cylinder Head

I tested the cylinder head for leakage and found that the exhaust valve was allowing a small amount of fluid to leak past the seat. I got a friend to recut the valve seat, and fitted a new exhaust valve. Other than this very minor issue, the engine was reassembled with no further problems.

Girder Fork Repair

While the cylinder head was away having the new seat cut, I got to work on the rolling chassis. The first task was to repair and refit the Heavyweight Webb forks.

I've written quite a lot about girder fork repairs in our Technical section, and most of the pictures used come from this bike, so I won't repeat it all on this page. Read our guides to girder fork repairs, bush replacement and spindle fitting in the Girder Forks section.

Wheels

The next job was to replace the badly worn rear wheel bearings. Since the original cup and cone type are no longer available, I skimmed the rear hub out to take a modern taper roller bearing. Not only are these readily available, but they should also last longer, make for easier adjustment, and require less maintenance.

Fitting modern bearings meant making a new wheel spindle, spacers, and nuts. I also took the opportunity to fit modern nitrile oil seals.

Once finished and refitted to the frame, the back wheel has all the new bits hidden, keeping the appearance of the bike as original and untouched.

Gearbox

The CS1 came to me with a 4-speed Sturmey-Archer gearbox fitted instead of the correct 3-speed Sturmey-Archer. Fortunately the correct gearbox came with the bike, albeit in a sorry state.

I suspect the bike had been in an accident and the kickstart had scraped down the road causing the damage. I had to find a new layshaft, kickstart shaft, and a host of other smaller parts before I could set about making them all work together.

I was able to buy a new end casting from Ken McIntosh in New Zealand. Machining the new casting proved to be a particularly interesting job so I decided it deserves a more detailed article of its own.

Exhaust

The bike came with a Brooklands can. Although it was a very nice original, it wasn't correct for this bike. Fortunately I had made excellent contacts at a foundry through Kingpin Components so was able to manufacture the correct Double Barrel Exhaust Silencer. These are now available for sale in our shop.

The only difference between the one on my bike and the ones offered for sale is that I painted the tubes matt black with a rattle can instead of stoved gloss black to tie in with the oily rag look.

Back on the Road

I had the bike finished in time for the 2018 riding season and it has been in regular use ever since.

Looking back, I'm very pleased I chose to recommission rather than restore it. It still wears nearly a century's worth of marks and repairs, but that's exactly what gives it its character. More importantly, it's back doing what it was built to do—being ridden. I am less precious about using this bike in the rain or on dirty roads than I am about my 1934 International, and I enjoy it all the more for that. Since finishing it, I've covered several thousand miles on day rides, weekends away and vintage rallies, and I wouldn't change my approach if I had to do it all again.

Here are a few pictures of it in use over the last few years. Click on any of them to enlarge.