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Blog
Welcome to the Kingpin Components blog, where I share my experiences of riding, restoring and maintaining classic motorcycles, alongside running Kingpin Components. Along with technical articles and practical workshop insights, this is a place to explore classic bikes as they are actually used — not as museum pieces, but as machines to ride, tinker with and enjoy. Long before Kingpin Components existed, I was a motorcyclist first, and that’s the perspective this blog is written from.
Here you'll find technical articles alongside posts about my own bikes, restoration projects, workshop jobs, rides, rallies and events, together with honest opinions, lessons learned and practical advice for using classic motorcycles on today's roads. There will naturally be some overlap with the work I do through Kingpin Components — parts I’m developing, interesting customer projects and problems that needed solving — but this isn’t a sales pitch. It’s simply a place for me to document the experiences that come from classic motorcycles being both my hobby and my business.
Workshop Update - June 2026
June has been more about riding than workshop time, but there are still two new technical articles, a customer Panther project, progress on my Norton CS1 and an update on parts coming back into stock.
Andy Marks
Jul 23 min read
AMAL Type 76 Carburettor Fault Finding and Repairs
When my Norton CS1 started fouling plugs and smoking badly after cylinder head work, I assumed the carburettor would need minor adjustment. The real fault turned out to be far more interesting and had probably been hiding in plain sight for years.
Andy Marks
Jun 243 min read
How to Check and Adjust Fuel Level on AMAL Pre-Monobloc Carburettors
This guide explains how to check the fuel height using a simple sight glass, identify common faults and make any adjustments required.
Andy Marks
Jun 223 min read
Workshop Update - May 2026
May was a busy month with bikes in the workshop, new products, Norton gearbox repairs and a successful trip to France on my 1929 Harley-Davidson. Read on for a look at some fantastic machines and what’s been happening in the workshop.
Andy Marks
Jun 15 min read
Taking a 1929 Harley-Davidson to France - La Balade des Vieux Clous 2026
This year I swapped my usual Norton ES2 for a 1929 Harley-Davidson on a trip to France. From fuel stops and roadside fettling to memories of my Granddad, here’s how a 97-year-old motorcycle coped with a long weekend abroad.
Andy Marks
May 2911 min read
Norton Dolls Head and Upright Gearbox Shells - Repairs and Modifications
A common problem with Norton Dolls Head and upright gearboxes is cracking or breaking around the upper mounting ears. This guide covers our preferred repair method, including modifying the top mounting arrangement, repairing worn pivots and machining new mounting components to prevent the problem returning. Why Norton Gearbox Mounting Ears Break Cracked or broken mounts are usually caused after the gearbox has come loose and been allowed to rattle. This wears the bottom pivot
Andy Marks
May 184 min read
Workshop Update - April 2026
April’s workshop update includes a stunning Velocette KTT, magneto verniers back in stock, new Norton engine stands, Stafford highlights and a look at what’s been going on with my Harley and CS1 this month.
Andy Marks
May 73 min read
Bonhams Spring Stafford Sale - What It Says About the Classic Bike Market
Stafford 2026 wasn’t just about the show bikes and autojumble — Bonhams’ auction offered a fascinating look at where classic bike values really are. Here are a few of the bikes that caught my eye, and what the results might say about the market.
Andy Marks
Apr 285 min read
Oil Tap with Cutout Switch - FAQ
This page answers the most common questions about our oil tap with cutout switch, designed to prevent wet sumping on classic motorcycles. It covers how the tap works, how to fit and wire it, and what you need to install one on your bike. How does the Oil Tap with Cutout Switch work? Our Oil Tap with Cutout Switch can be connected to bikes with magneto or coil ignition. They ensure that, if the oil tap is 'off', the switch will stop any sparks and the engine cannot be started
Andy Marks
Apr 134 min read
Workshop Update - March 2026
March’s workshop update includes new technical pages, an expanded range of bearings and oil pipe, plus a look at a couple of customer bikes and ongoing work in the workshop.
Andy Marks
Apr 74 min read
Introducing Andy - The Man Behind Kingpin Components
Meet Andy Marks, founder of Kingpin Components. Learn how restoring classic motorcycles led to making and supplying hard-to-find vintage bike parts.
Andy Marks
Mar 263 min read
Wet Sumping - Why It Happens and How to Stop It
Wet sumping is a common issue on classic motorcycles where engine oil drains from the oil tank into the sump while the engine is not running. This guide explains why it happens, how different types of oil pumps affect it, and the practical solutions available to prevent it, from maintenance and riding habits to anti wet sumping valves and oil line taps. What Is Wet Sumping and Why Do Classic Motorcycles Do It? Wet sumping is when engine oil slowly drains from the oil tank int
Andy Marks
Mar 235 min read
How to Convert Road Speed to Engine RPM
This guide explains how to convert road speed into engine RPM using the gearing and rear wheel size of your motorcycle. By using the number of teeth on the engine, clutch, gearbox and rear sprockets together with the rear wheel diameter, you can convert miles per hour into rear wheel speed and calculate the corresponding engine RPM. A downloadable spreadsheet is also included to automate the calculation. Using Motorcycle Gearing to Calculate Engine RPM This is very useful w
Andy Marks
Mar 172 min read
How to Convert Engine RPM to Road Speed
This guide explains how to convert engine RPM into road speed using the gearing and rear wheel size of your motorcycle. By using the number of teeth on the engine, clutch, gearbox and rear sprockets together with the wheel diameter, you can calculate rear wheel speed and convert it into miles per hour. The article also includes a spreadsheet tool that performs the calculation automatically. If you want to perform the opposite calculation, see our guide on converting road spee
Andy Marks
Mar 172 min read
OHV Norton Piston Options
This guide looks at the piston options available when increasing the compression ratio of an OHV Norton engine. Standard ES2 pistons, modified 16H pistons, BSA B40 scrambles pistons and custom piston designs are compared, along with the advantages, drawbacks and machining work required to make each option work. Standard Norton ES2 Piston As you'd probably expect, standard ES2 pistons offer the simplest option during an engine overhaul as they fit straight into the engine. The
Andy Marks
Mar 174 min read
Norton SOHC Cambox Tunnel Repair
This guide explains how to repair the damaged camshaft tunnel in a Norton SOHC cambox, a common issue on these engines. The article shows the full machining process required to restore the tunnel, including boring the cambox, turning a replacement tunnel in the lathe, drilling oil drain holes and reassembling the cambox correctly. The Common Problem with Norton SOHC Tunnels One of the most common problems with the Norton SOHC cambox is damage to the tunnel that the camshafts
Andy Marks
Mar 174 min read
Velocette M Series Cam Data
From the first MOV to the last Thruxton the M series Velocettes all used the same basic design for their cams. The profiles varied but all are interchangeable from one model to another. Below is a table showing the timing figures for each cam along with the checking and running clearances and finally a note on what they were originally fitted to. Return to Velocette Technical Guides or Technical
Andy Marks
Mar 171 min read
Pre-war Norton Engine Numbers
Pre-war Nortons did not have consecutive or matching engine and frame numbers. The only way to properly identify and date these engine and frames is to contact someone with access to the factory records. The Norton Owners Club has them. Pre-war engines can be dated from the number. The table bellow shows the range of engine numbers from 1923 through until 1939. 350cc engines used a separate range of numbers as follows: From 1929-1936 the ranged from 1000-6200 From 1937-
Andy Marks
Mar 161 min read
Post-war Norton Engine and Frame Numbers
Post-war Nortons can be easily dated and identified from the prefix. The letter denotes the year and the number denotes the model. The same numbering system was used on both engine and frame, and they should match on an original machine. The two tables below show the pre Commando models up to 1960. Return to Norton Technical Guides or Technical
Andy Marks
Mar 161 min read
OHV Norton Cams
Post 1948 OHV Norton valve timing is very ‘soft’. If you are trying to get the best out of your engine it is one area that significant gains can be found. You can get a bike to go well with standard cams but it is important that the timing is spot on - don’t rely on the dots! You can check your valve timing against the figures shown on this page. If you would like a little more performance from your bike - read on to see what your options are. Irving’s Recommendation This dia
Andy Marks
Mar 162 min read
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