Check Radial Runout When Installing New Tires

When installing a new tire, it’s a good idea to put the rim on a truing stand to measure radial runout. Check lateral runout at the same to ensure it’s withing 0.80mm. Radial runout is up and down variance from concentric. If the rim has, say 0.80mm or less radial runout, proceed with tire mounting. If there’s more than 0.80mm, a wire spoke rum needs to be re-trued to bring the radial runout within specifications.

A aluminum-alloy cast rim may need replacing depending on how far above 0.80mm the radial runout actually is. Most motorcycle companies advise replacement if radial runout exceeds 0.85mm. It is easy to instruct this, but not everyone has deep pockets with fat wallets, so compromise may same some money.

I do not get worried when replacing a rim for less fortunate customers until hitting 1mm radial runout. I explain the pros and cons and let the customer decide. However, if it goes higher than 1mm, then it becomes a safety issue in my mind, and I will dig my heels and refuse to re-install the rim.

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Crankcase Pressure and Engine Performance

Nearly a month ago, we looked at the problems created by crankcase ventilation. These ventilation systems route the combination of gasses escaping past the piston rings, mixed with vaporized engine oil from the crankcase, to the intake tract, where they are supposed to be burned on a second trip through the combustion chambers.

Although Positive Crankcase Ventilation (PCV) systems have been required since 1961, they have serious drawbacks – mainly the accumulation of carbonized oil on the walls of the intake and exhaust passages, the backsides of the valves and in the combustion chambers, where it badly reduces airflow and can cause overheating. In addition, oil particles in the combustion chambers can initiate detonation, quickly creating major damage. Let’s look at what you can do to avoid such problems on your own motorcycle engines.

It has been reported that, at idle, typical blow-by composition is 67 percent oil, 22 percent fuel, 10 percent water and 1 percent solids by weight. An inevitable by-product of combustion, water is the greatest single cause of preventable engine wear, creating corrosion by oxidation and acid formation. Tests have shown 0.2 percent water in the engine oil is typical but levels of .4 to .5 percent are not uncommon, and at these higher concentrations, free water is likely to separate out as the engine cools. Plus, ironically, the situation is made worse by the water dispersal additives in modern engine oils, and the use of E10, E20 or E85 fuels (containing 10, 20 and 85% ethanol) that both attract water and are more electrically conductive than gasoline, creating galvanic corrosion.

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Cleaning Your Chain and Brake Discs

If you’ve got a motorcycle with a chain, then you’ll know that cleaning the chain is a filthy dirty job. No-one likes to do it. While it’s not as dirty a job, cleaning your brakes is also very important maintenance that you should be doing. Both dirty deeds will help the performance, riding and longevity of your motorcycle – and there is help out there to make both jobs easier.

We grabbed some specialist cleaning products and got to work… and still got filthy dirty in the process. Maybe you can be more careful! We bought online a motorcycle cleaning set. But let’s get started with the chain.

Find yourself a spot where you can lay down some old newspapers and cover up any parts of your motorcycle that you don’t want to cover in gunk. Now start spinning the rear wheel and spraying the chain cleaner onto the chain. It does help if you have an assistant, but it can be done alone if need be. Now spray a small section at a time and use a brush and scrub the chain clean, while spraying each section with more chain cleaner.

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Under Pressure - Crankcase Ventilation

Piston rings never fully prevent combustion gases from escaping into the crankcase when an engine is running. Leakage happens even when the best cylinder finishing and highest quality piston rings are employed, inevitably getting worse over time, and the issue creates two distinct problems.

One, some amount of power is continually lost to this leakage. And two, the engine designer must find a way to minimize the buildup of blow-by in the crankcase, which creates both corrosive contamination of the oil supply as well as excess pressure that must not be allowed to blow out seals and gaskets.

There are two readily available methods to determine ring sealing: the simple ‘compression test’ and the more accurate ‘leak-down test.’ To perform a compression test, a pressure gauge is screwed into a spark plug hole, and while the throttle are held wide open so as not to restrict airflow, the engine is cranked over for several seconds until the gauge stops rising. Each cylinder is tested in turn and the pressures are compared to one another. We’d like to find them all within 10 percent of one another and close to the maximum pressure specified in the service manual.

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Carburetor Cleaning, Rebuild or Repair

Reliably delivering the right amount of fuel and air to our motorcycles’ engines goes right back to first principles. Old, worn carburetors cause much aggravation to many motorcycle owners. Ultrasonic cleaners have been a major boon to those happy to spanner their own motorcycles.

It’s also meant that a good amount of people are offering ultrasonic cleaning ‘services’ which vary wildly in their quality. Some, we hear, do little more than chuck the carburetor in whole without bothering to take it apart. Ultrasonic cleaners are not the universal panacea they’re perceived to be. It takes a little more than dumping carburetors in the bath and hoping for the best. They have to be properly stripped and inspected.

There’s no point cleaning carburetors with worn-out parts, and stripped-down carburetors will clean much better.

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Keep the Engine Cool - Use the Right Cooling Liquid

The liquid in your radiator not only stops your engine from overheating, it also protects against corrosion and prevent calcium build up inside your cooling system. Often the cooling liquid specified by manufacturers has some other beneficial properties, like absorbing heat even better than plain water.

Not all cooling liquids are the same, and it’s unwise, and in some extreme instances even dangerous, to mix different cooling liquids together. It’s therefore important to topping it up with the right liquid, but replacing it with fresh cooling liquid is a good insurance. You should also consider the properties of the cooling liquid, as the differences in engine cooling can be up to 20 degree Celsius.

To avoid risk of burns, replace the cooling liquid with a cold engine. With the motorcycle on a stand, put a container that’s large enough to hold all the fluid underneath the drain bolt at the bottom of the pump impellor cover – the one near the bottom that is normally away from the sealing edge bolts. But to be sure check your owners manual for the location of the drain bolt.

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Check Valve-Clearance Importancy

As far as routine maintenance goes, no one is ever in a mad hurry to check and adjust valve clearances. It’s as involved as mechanical tasks get, short of a top-end or engine rebuild. However, you ignore them at your peril. Incorrect valve clearances lead to lumpy running, poor starting and, in extreme cases, burnt-out valves.

Everyone knows someone whose valve clearances have been rigorously checked, but adjustment has never been required. The brand name ‘Honda’ usually figures in such tales. Far be it from us to doubt the veracity of these legends, but the fact is that valves can and do go out of adjustment and motorcycle brands and usage really don’t seem to have much bearing on matters.

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Replace Ball Bearings for your Motorcycle

So you need a new ball bearing for your Honda this or Ducati that, you say? Actually what you need is the same type of generic bearing your motorcycle’s manufacturer used.

Very few bearings are unique to a motorcycle or manufacturer, although the prices dealers charge can be uniquely rude or even ridicules priced up to 15 times the cost of the OEM value

By cracking the code stamped on the bearing, you can buy from a bearing manufacturer, engineer part store, or online. Just be sure to stick with name brands like SKF, FAG, Kyoto or NKE.

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Static Sag for Small Motorcycle and Scooters

Most motorcycle owners are not really sure what would be a good baseline static sag setting for the suspension. Static sag is how much your motorcycle settles on its suspension with you or the rider in the seat.

A good amount of motorcycles sold in Thailand are not set-up for the average European or American rider, which results in a suspension that works less correct.

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Dead battery - Explore Your Options

Even when you think your two-wheeled best friend is running without issues, it might be time to put a new battery in your motorcycle. But what type of battery should you buy? Life was simpler a couple of decades ago, when only conventional batteries were available. Several years ago, absorbed glass mat (AGM) batteries became available, and more recently, lithium iron phosphate batteries have hit the market.

Conventional batteries are also known as lead-acid, or flooded electrolyte, batteries. These batteries contain several series of positive and negative plates of different materials (including lead); each series of plates is contained within a sealed cell. The plates are immersed in electrolyte, which is a mixture of sulfuric acid and water. It is the chemical reaction between the electrolyte and the plates that produces electricity, at a rate of roughly two volts per cell, which is why there are six cells (and six filler caps) on 12-volt batteries.

Note that 12 volts is a nominal value, and batteries are actually designed to work ideally between 13.5 and 14.5 volts, with a static voltage of at least 13.2 volts. That means that if your voltmeter reads just 12 volts, it's time to put your battery on a charger.

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How many times have you crashed your motorcycle in the last three years?

  •  Never
  •  Once
  •  Twice
  •  Three times
  •  Four times
  •  Five times
  •  More than 6 times
  •  More than 10 times
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