A friend of us runs a successful motorcycle repair shop and does general servicing. His bread and butter is servicing anything with two-wheels regardless the engine size. He loves it when non-abused Honda Wave or similar motorcycles come in for their annual services. What he does not live is elderly Japanese four-cylinders coming in with a string of problems, with multiple causes and a big bad dark cloud hanging over parts availability.

Personally we love nursing an ailing old Japanese gem back into good health and loathe working on bland modern big bike commuters, so when our friend had a problematic Honda CB400/4 he asked the customer if he would be happy with hiring some external experts, who were more geared up for errant classics. Of course we never will call ourselves experts regarding an old CB400/4s…

The elderly diminutive Honda four-cylinder had various medical complaints, but the most frustrating was its inability to start and run, making it paramount for us to collect it in one of our pickup trucks. Oddly, I had never ridden an Honda CB400/4 this old and that wasn’t about to change unless we could figure out what was wrong with it.

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Wheel bearings are among those vital motorcycle components that are out of sight and out of mind... until something goes wrong. Wheel bearings failures can do expensive damage to your motorcycle and can result in a dangerous loss of control and a crash as well. So let’s give them some love!

Check your motorcycle’s owner’s manual for wheel bearing inspection intervals and maintenance procedures. Most motorcycles now have non-adjustable ball-bearing wheel bearings, and usually they have shields and are non-greasable. Wheel bearings often last the life of the motorcycle, but riding through deep water, on rough terrain on sandy and dusty roads, spraying the bearing areas with high-pressure washers, overloading, and failing to lubricate (if needed) can shorten their service drastically.

Follow factory recommendations when you inspect them, and replace them if any signs of looseness or wear is present.

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No, we are not referring to your poor posture after a long day in the saddle. Rider sag relates to the amount that a motorcycle’s suspension compresses when you sit on it, and there is generally an optimum setting for different motorcycles and applications.

To work out rider sag we must first determine if the static sag is in the correct ‘zone’ (around 5 to 10mm). Static sag is how much of the suspension travel is taken up by the motorcycle’s weight. Then we check the sag with the rider on board.

It may sound complicated but it’s not, and we’re going to give you 10 simple steps to check this at home – all you’ll need are a few tools and a couple of willing helpers. Not only does this procedure assist your motorcycle to operate in optimal range of its suspension travel while riding, it also reveals whether the spring rates on your motorcycle need to be changed to suit your weight.

We’ll start with the front end, so the wheel needs to be off the ground with the front forks fully extended.

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Spokes are so often forgotten and over looked, yet there are so many of them that there is a good chance one or two are beginning to work loose and could cause a problem.

To illustrate how important it is to check your spokes for tightness, pretty much every professional mechanic that deals with spoked wheels will check every single spoke every time the motorcycle comes in for an inspection or checkup.

But you can’t just go wrenching on your spokes willy-nilly or the wheel will come out of true. To make sure you tighten the right amount we suggest using a spoke torque wrench set at about 48 inch-pounds (5.42 Nm).

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When discussing steering geometry people often only think in terms of rake and trail, but these are related by other parameters as well. Specifically, tire rolling radius and the offset of the wheel axle from the steering axis. Wheelbase should also be regarded as part of the equation, too.

Tire radius and trail are the two most important factors which affect how we perceive the steering feel. Trail is determined by the rake, offset and tire size.

I am often asked if there are optimum values for these parameters. The short answer is no; values have varied over time and each type of motorcycle. Sports and racing motorcycles need quick steering bordering on instability, touring motorcycles are concerned with stability.

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Let’s look at the science behind getting the it right. Of all motorcycle engineering’s dark arts, chassis tuning is the most transformational, the most useful, and the least understood. Power, they say, is nothing without control. Control is only gained when a motorcycle’s tires are firmly in contact with the ground, And the components that maintain this critical union of rubber and road are what’s known as a suspension system.

Now, although this will instantly conjure mental images of a fork, shock, swingarm and the related springs and things that let them compress and extend in a controlled manner, they’re not the only parts that affect bump absorption and road-holding.

The motorcycle in its entirely is a suspension system constantly yielding to impacts and rider inputs through flex in the frame- tires, wheels, triple-clamps and even the engine. The suspension components are just the last line of defense in the battle for wheel control and chassis stability and are, generally, the only element of ‘give’, which can be adjusted for resistance and rate of movement.

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Repairing the damaged plastics of a motorcycle is one thing; painting them to a satisfactory level is an altogether different matter. Unless you have the facilities to properly spray it’s arguably a job that is best left to the professionals.

However, should you wish to take the plunge and have a go there are almost limitless tutorials online that will take you through preparations, operating conditions, paint types and numerous other key areas. One thing to be aware of with plastics is getting the right primer; without this vital first step, paint is unlikely to adhere to the plastic properly.

The hardest plastic to cut in terms of paint adherences is anything regarded as a polyolefin. If the panels you’re working on look and feel like a washing up bowl then they’re almost certainly polyolefin in nature. Polyethylene (PE) and polypropylene (PP) are the most common and are typically found on step-through leg shields and mudguards.

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A damaged panel can cost a fortune to replace. Therefore we decided to tell how to repair plastic panels as good as new with just a few tools and cable ties.

Small scrape, an embarrassing drop or an errant boot can all damage your motorcycle’s paintwork. Motorcycles can be much trickier than cars to repair – they have a variety of different materials, have intricate curves, often use transfers over paint, and even the paint codes to get the right color match can be tricky to find sometimes. And if your motorcycle is an older model, replacement parts can be elusive.

After checking a replacement part isn’t an economical solution, your next choice is to repair the damage. It’s easier than it sounds – so let’s have a look at how you can repair plastic for as little money as possible using heat, filler, cable ties and a little help from some friendly professionals.

Assess the Damage and Sort your workspace. Our panel had taken the brunt of an impact around the clutch area, with scrapes through the paint to the plastic, and two holes. We built a makeshift bench to hold the panel, with packing foam to prevent scratches. This gives us a nice height to work from.

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Cables are fast disappearing on the larger modern motorcycles, but there are still plenty around and most riders ignore them until they break or cause a problem. This is partly because modern Teflon-coated cables have an amazing lifespan and need very little maintenance.

But there’s still a substantial gain in performance and durability available from steel-wound cables if they’ve lubed regularly, and there’s still plenty of steel-wound cables in use. You'll be amazed at how much lighter a throttle or clutch will feel if it’s given a good dose of lubrication, especially if it’s been allowed to gunk up.

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If you have a older motorcycle that’s on the edge of 10 years old or that can be classed as a project motorcycle, you should arm yourself with a wire stripping pliers and ratchet terminal crimps, this simple electrical tools make repairs and modifications so much easier.

The wire strippers are satisfying to use – neat, with easy exposure of the copper strands for fitting connectors or splicing in joins every time. The jaws have a variety of sizes to suit common wire diameters on Japanese or European motorcycles. Then you bring the ratchet crimps in to play.

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