Improving Classic Motorcycle Engines by Graham Blighe

This book aims to give advice to cure leaks, reduce vibes and boost performance. So who better to review it than a professional motorcycle engineer?

‘Improving Classic Motorcycle Engines’ is the third in a series of books by Graham Blighe, and it follows the same format as ‘Improving Classic Motorcycles’ and ‘Magnetic Speedometer Repair.’ It’s a 96 page, large format softback with mono illustrations, and it explores various aspects of four-stroke motors. The chapters look at oil tightness, crankcase breathing, valve timing, exhaust systems and vibration.

The author is long-term classic bike owner and rider who uses his Bantam, Starfire 3TA and Daytona as year-round daily transport. His view is that old bikes can be made to work dependably and be suitable for today’s roads, and his books aim to help other riders enjoy greater comfort and reliability from their machines.

The six chapters in ‘Improving Classic Motorcycle Engines’ cover stopping oil leaks; crankcase breathing; valve timing; valve lift graphs; reducing vibration and high performance exhaust systems. If you’re not comfortable or familiar with engine internals, then obviously you should proceed with caution… it might be better to get to grips with a basic rebuild before making alterations to your motorcycle’s standard set up.

Bearing that in mind, we asked a professional automotive engineer to give us his opinion of the book; Martyn Roberts is well known in industry circles, in both the bike and car worlds. Now semi-retired, his career has been mainly as a designer, project manager and chief engineer with companies like Triumph, Cosworth, Ricardo and Prodrive. Over to you, Martyn…

I approached this book with some scepticism. After all, why would you buy an old, outmoded motorcycle and then try to improve it? Just buy a later model surely? As I read through it, I realised I had been a bit harsh.

The author deals with a number of issues in great detail, such as checking and correctly setting the valve timing, or eliminating persistent oil leaks. Some useful tips are included – like turning a tappet adjusting screw through a prescribed angle instead of using a feeler gauge to achieve the correct clearance, if the valve tip is worn.

The style is similar to the old ‘dirty fingernail’ magazines of the 1960s that showed you how to fix things with clear instructions and illustrations. I didn’t agree with all the author’s conclusions though. He admits that some of his ideas about vibration and exhaust design are based on guesswork. He also devotes space to describing balancing a camshaft to help reduce vibration, despite expressing clear doubts about its effectiveness. Well, since out-of-balance is influenced by the mass, radius of the part and speed squared, I should jolly well think so – a complete waste of time.

You have to be seriously interested in the subject matter to have the patience to read the text properly – it only works if you read and digest every word. Mind you, reading it won’t take as long as carrying out the actual jobs described so I imagine patience won’t be a problem for the target readership.

It’s a shame the book doesn’t cover more topics. References are made here and there to previous companion volumes but within the covers of this one we only get to hear about oil leaks, crankcase breathers, cam timing, vibration and exhausts.

Despite my criticisms, maybe reading this book will encourage more people to tinker with old bikes, to improve them and enjoy them. I’m sure that was the author’s intention and a very worthy one it is, although a little knowledge can be a dangerous thing, as they say. Of course, those already blessed with the confidence to attempt this sort of work may feel the book has little to teach them.

RC Reviewer: Martyn Roberts

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