Shop Talk | The New Rider’s Guide To Basic Maintenance Part 2

Last issue we covered some basic maintenance tasks. In this installment, we'll delve a little deeper.

Last issue we covered some basic maintenance tasks. In this installment, we’ll delve a little deeper.

Spark plug replacement

Although the days of routine plug failure are well behind us, spark plugs—like oil, filters and tires—are expendable items, requiring periodic inspection and replacement.

Before we look at the plugs let’s cover a few basic rules. First: spark plugs should never be removed or installed while the engine is hot. There are exceptions to this rule, but for our purposes, the engine should be stone cold whenever you’re working with the plugs.

Second: You’re going to need two special tools to remove, install and inspect the plugs. The first is a dedicated spark plug socket of the correct size, the second is a spark plug gapping tool. For the latter, get the traditional wire type, as the sliding fit ones aren’t so accurate. Both are readily available through your favorite tool supplier or motorcycle accessory catalog. But why a dedicated socket? Spark plug sockets have inserts in them that protect the porcelain portion of the plug and prevent the plug from cocking in the socket, plus it’ll hold the plug in the socket, all of which makes removal and installation without damaging anything far easier.

Finally, if you don’t have access to an air compressor and blow gun, grab a can of compressed air (the ones used to clean computer keyboards work fine), some sort of anti-seize compound, and a small tube of Dielectric Silicone grease (both available at any auto parts store.)

Removing the plug

Remove any extraneous parts, like the fuel tank or cosmetic covers, that may be in the way. Motorcycles generally use hard plastic plug caps, so removing them, along with the attached coil, is straightforward; grasp the cap (not the wire) and give it a twist as you apply gentle upward pressure. It should pop right off; if it doesn’t work, try wiggling it gently as you lift. In all cases, resist the temptation to yank on the wire—all that’ll do is break the connection and create more problems.

In some cases, a “stick” coil may be attached directly to the plug. To remove them, first remove any retaining bolts and disconnect the primary wires, then remove the coil using the twist and lift method.

Blow any debris away from the spark plug base. Lungs and a soda straw will get it done, if you’ve got nothing else. Then remove the spark plug. After a turn or three, the plug should spin out easily, though it’ll probably still require a wrench to turn it. If the plug puts up a fight, try a shot or two of penetrating oil but if that doesn’t do it, gently thread the plug back in and have your shop take a look at it. It’s probably fine; seized plugs are rare these days, but it takes some experience to tell the difference between a plug that’s a little stiff and one that’s galling the threads on the way out.


Now that the plug's out take a moment to inspect it; the plug is a "window" into the combustion chamber, so careful observation can tell you a lot about how the engine is running. A rundown on plug appearance and how it relates to combustion would take up too much space here, so head on over to, for appropriate color photos and descriptions.

Allow me to digress for a moment and point out that if you’re riding a stock motorcycle and it’s running well, there’s really no need to perform routine spark plug inspections. It’s just as easy to replace them when the time comes and avoid the extra work. That’s just my opinion of course, but it’s based on replacing thousands of plugs over the last 45 years.


Before installing any plug, new or used, you’ll need to check the gap. The gap is the distance between the ground or side electrode and the center post of the plug. Your owners’ manual will provide the correct gap, as will the box the plug came in and the plug manufacturer’s catalog. The plug maker’s gap may not jibe with the one listed in your manual; if it doesn’t, I’d defer to the owner’s manual.

The gapping tool’s wire gauge should be a sliding fit between the side and ground electrode. Bend only the side electrode to adjust the gap, and try to keep it as square as possible to the center post. You don’t have to go crazy here—plugs aren’t super sensitive to gap, ballpark distances work well enough for most applications, but like anything else, the more accurate you get the better the engine will run.

Coat the plug threads with anti-seize compound, and thread the plug into its hole. If the plug is difficult to reach, slip it into the socket or place a small piece of fuel line over the porcelain portion of the plug to help you lower it into the hole. If everything is perfect or close to it, you should be able to thread the plug home using nothing more than your fingertips. In the real world it doesn’t always work that way, especially when the plug threads into a recessed, impossible to reach hole. In all cases, it’s perfectly acceptable to run the plug in using a socket, so long as you only use light pressure. If you have to bear down, especially at the start, something is wrong, so stop and start over. A cross-threaded plug is no joke, but it’s easily avoided with a little care.

Once the plug bottoms against its seat, torque it to the manufacturer’s specifications (preferable) or, lacking a torque wrench, give it another ½ to 2⁄3 of a turn to seat and crush the gasket. I like to apply a dab of dielectric grease to the plug tip before installing the cap, and if the plug uses a rubber boot, run a little around the edge of the boot to ease installation.

That’s it; replace anything you had to remove to get to the plugs, and you’re all done.

Inspecting Tires

At the risk of making a bad pun, everything rides on the condition of the tires. Neglect them and the likelihood you’ll experience the dubious pleasures of asphalt surfing becomes greatly increased.


Under- or over-inflated tires create handling problems, increase wear, and compromise safety, so get into the habit of checking them on a routine basis.

Good tire gauges are inexpensive and readily available so there’s no excuse not to own one. As an experiment, I once compared the readings of a 99-cent gas station special I picked up against the $65 gauge I used on my race bike, and both were dead on. I’m not telling you to buy a 99-cent gauge, but I will say they’re better than guessing, and a very decent gauge, like the Milton S-921, typically retails for around five bucks.

The tire pressure specs are listed in the owner’s manual and there’s always a sticker on the frame or swing arm conveying the same info. Because the pressure increases as the tire warms up, always check and adjust the tires when they’re stone cold. How often should you check them? Once a week should do it under normal circumstances; daily if you’re touring.

The condition and depth of the tread is equally important. Run your hand lightly over the surface of the tire. If there’s a noticeable cupping or, more accurately, scalloping of the tire, it’s time to start thinking of replacing them. Don’t be overly concerned about the fact that the tire is cupped; it’s a normal state of affairs, though cupping is exacerbated by low tire pressure, so if your tires cup early and often you may want to check the pressures more frequently and possibly increase pressure by 2 – 3 PSI. By the way, cupped tires tend to make a lot of noise, so humming tires are a sure sign replacement time is drawing near.

Checking the tread depth is straightforward. All tires have wear indicators built into them. Most often these appear as bars across the tread, and when they’re visible it’s time to replace the tire or park the bike. The problem is that wear bars are more or less a final warning, so you’re better off replacing the tires before they reach that point. Tire manufacturers generally agree that a motorcycle tire should be replaced when the tread depth reaches 2⁄32 of an inch or 1mm. You can measure that by using a tread gauge; the Milton S-448 retails for about five bucks at any auto parts store, or you can use a penny. Stick the penny into the tread with the top of Abe’s head pointed towards the tire; if his whole head is visible, the tire is worn out.

Don’t forget to give the sidewall an occasional glance. Look for cuts, bulges, and cracks; all are indicative of serious tire casing problems. If anything suspicious is found, trailer the bike to your favorite tire guy.


Brake fluid is hygroscopic, meaning it’ll absorb water from the atmosphere, and as it does, its effectiveness diminishes. The solution, no pun intended, is to inspect the brake fluid on a regular basis, and change it according to the manufacturers schedule, which in most cases is every two years or so. Inspecting the brake fluid should take about 30 seconds. Take a look at the master cylinder reservoir sight glass (or the reservoir itself if it’s clear plastic); there should be two lines indicating the minimum and maximum fluid levels. Ideally the brake fluid should fall midway between them. If the fluid is on the low side, it’s generally an indication that the brake pads are worn, so inspect them, and check for leaks before adding fluid. In any event, never add fluid past the max line; brake fluid expands with heat, so any extra may leak past the cap vent and make a mess.

The other concern is the color of the fluid. Fresh brake fluid might best be described as clear with an amber tint. There are exceptions, as some specialty brake fluids are tinted in different colors to avoid confusing them. For example, silicone-based DOT 5 fluid is tinted purple, and is made only for brake systems designed to use it.

If the fluid is water clear or has a slight amber tint, it’s fine, but if it’s muddy and dark, a change is overdue.

There are a couple of things to remember about brake fluid. Foremost, most brake fluids are corrosive, and will damage paint, some alloys, many plastics and your eyes in short order, so always exercise care when working with or around it. Second, never second-guess the manufacturer’s recommendations. If they recommend using DOT 4, than that’s what you should use. Yes, some older brake systems are compatible with DOT 5, but I don’t recommend using it unless the brake manufacturer approves it.

Brake pad/Shoe Inspection

Inspecting the brake pads takes only a flashlight and a limber back. All brake pads have some sort of built-in wear indicator, most often a groove (the most popular) or a step in the pad; less often, it’s a paint mark. As the pad wears, the indicator lets you know how much of the pad is left. Since each manufacturer uses their own indicator, you’ll need to consult your owner’s manual or, if aftermarket pads have been installed, the pad maker’s catalog or website. To check the pad, simply sight along the edge of it and check the indicator.

While you’re down there, take a look at the rotors. They should be smooth, though some wear, discoloration and even a few small scores are normal. Likewise, inspect the brake hoses, looking for worn and chafed sports, bubbles in the line and weeping where the fittings are crimped on.

Drum brakes are rare these days; even the entry-level bikes are doing away with them, but they’re still out there. Many of them have an inspection port in the backing plate. Remove the rubber plug to get a good look. Other drum brakes use an external wear indicator that makes inspection even quicker. As a rule, brake shoes should be replaced when the thinnest portion of the shoe measures about 1.5 mm or a 1⁄16 of an inch.


Drive shafts require little more than a periodic oil change, and the occasional glance to see if any leaks have developed. Belts require just a bit more attention, and chains the most.

Inspect the belt’s slack adjustment. Every manufacturer has their own method and specs, and a tension gauge will often be required to accurately measure and adjust the tension. I’ll tell you to defer to the shop manual for the specifics, but as a rule if you can twist the belt past 45-degrees at its slackest point it’s on the loose side. Periodically inspect the belt for physical damage, like chafing on the edges and embedded stones. Serious damage means it’s time for a new belt.

Drive chains require the most maintenance but in my experience, if you show them a little love they’ll last upward of 20K miles and rarely need adjustment. Most importantly, keep them clean and lubricated; how often is dependent on circumstance. I lube mine every 500 miles but that might be halved if I’m touring in the rain and putting in long days. That aside, stick to the factory recommendations and you can’t go wrong. Whenever you lube the chain, keep an eye out for rusted or kinked links, hooked sprocket teeth, and proper adjustment. Worn components should be replaced ASAP, with the recommendation that you replace both sprockets anytime the chain is replaced. Installing a new chain onto worn sprockets will cut the new chain’s life in half.

That’s All Folks!

Riders that are new to all of this may find some of the foregoing somewhat daunting. That’s perfectly understandable, but stick with it, and you soon find that the ability to maintain your own motorcycle is nearly as satisfying as riding it. cr

Touch Ups

Nicks, dings and scratches are an inevitable if unfortunate part of motorcycling. Despite our best efforts, it’s hard to keep that finish pristine. Stones fly, wrenches get dropped, and stuff happens, including the normal wear and tear of simply riding the motorcycle.

Some guys just blow it off, figuring it’s all part of the fun, and to some degree I agree with that philosophy. A ridden bike is always going to show some miles, and I think motorcycles should wear their battle scars proudly.

But here’s the thing. While it’s true that paint is used to pretty things up, its primary purpose is to protect bare steel from corrosion, and therein lies the larger problem. Once the paint’s been chipped, moisture can attack the underlying metal. Once it gains a foothold, pretty soon you’ve got rust, flaking paint and you’re in the market for a new bike. For that reason if no other, it’s always a good idea to touch up those little dings and nicks that your bike incurs, no matter how inconsequential they might seem. The question is what to use, and how to apply it.

Many manufacturers supply touch-up sticks, which are small tubes of paint color-matched to their bikes. You can also find paint through the aftermarket. ColorRite ( is one particularly good source, while PJ1 is another, though they tend to cater to the off-road market. If you're willing to experiment (and as much of a cheapskate as I am), you can usually find primary colors on the shelves of your local paint or hardware stores that'll match your paint, and are quite a bit cheaper than the factory or aftermarket paints. In particular, Rustoleum has a nice line of 2-ounce touch up/small project paints that work really well.

Applying the stuff without making a mess can be tricky, however. Most chips are just small craters that need filling, so what you want to do is place a small blob of paint in the hole so it’ll flow outward until it reaches the edges of the chip. Consequently, paint brushes aren’t always the best choice, and the ones that come in the touch-up sticks are particularly bad—they’re generally too big and too stiff to place a tiny drop of paint precisely into the center of the crater, so you end up painting over the thing, which protects it, but often looks worse than the original ding.

If the ding is large, I use a cut-down artist’s brush. Artists brushes are soft, so you can move the paint around if need be, and you can taper them to as fine a point as you need. If the ding is smaller, I’ll use a toothpick, or less often a cardboard matchstick to place a droplet of paint. The paint will shrink as it dries so several applications may be necessary if you’re looking for a perfect finish. Let the paint dry for 24 hours before applying any wax.