Motorcycle Instrument Install - How To

How to Instrument Install

Idiot lights are fine as far as they go. They're small and relatively unobtrusive, so a number of them can be clustered together in an instrument panel, or arranged neatly across the bottom of something like a speedometer or tach. Furthermore, they're easy to check with a quick sweep of the eyes and when there's the problem, they stand out like a sore thumb. Lastly, they're cheap to produce, which are all good reasons for OEM manufactures to use them.

Unfortunately, because indicator lights are either on or off, under most circumstances by the time one's winking at you the damage is done, and nine times out of ten, your only recourse is to shut off the engine and start walking.

On the other hand, because gauges allow you to monitor things on a regular basis you can normally catch problems as they develop, when you can still do something about them, rather than wait for them to become full blown, "uh oh, my bike is broke down on the side of the road," disasters.

For example, by the time a high water temperature indicator light comes on, the engine is either already overheated or dangerously close to it, so your only real option is to pull over as quickly as possible and let the thing cool off, before you can affect a repair... assuming of course that is even possible. On the other hand, since temperature gauges constantly monitor and display the coolant temperature, it very easy to see when things are getting off kilter. Generally, the needle will start to register higher than normal readings some time before the engine overheats so in most cases you'll have ample time to affect repairs before there's a disaster.

On the down side, gauges take up a lot more space than indicator lights, and they're more expensive, so few manufactures supply them as standard equipment, especially on cruisers, so if you want them, in most cases you're going to have to install them yourself.

Fortunately, installing a set of gauges is relatively simple. You'll need to do a little bit of wiring work, and you'll need some basic hand tools, but if you can change your own oil (or even if you can't), you should be able to install something like a voltmeter or oil temperature gauge in an hour or three at most.

Here's how to do it. Gauges commonly consist of three parts, there's the gauge itself, a sending unit (which won't be required for all gauges), and a mounting bracket (if required.) In some cases, the sending unit will be included with the gauge, in other instances it'll have to be purchased separately, so check with the supplier beforehand. As an aside, this is perfectly logical because while something like an oil pressure gauge itself is more or less universal, different applications require different sizes and styles of sending units.

As a rule, installation instructions are also provided. But as always, it won't hurt to have a service manual handy, just in case something doesn't seem kosher, or you run into an unusual situation.

For our purposes, we selected an oil temperature gauge and a voltmeter. Both air and liquid cooled engines do their best work when the oil temperature runs somewhere between 200 and 220° F, although some will run closer to 230-235° (F) if it's really hot out and the engine is under a load. Once the temps hit 250 degrees (F) you've got problems, so keeping tabs on the oil temperature is one way to ensure your engine's longevity. If nothing else it'll tell when you when it's time to pull over and let the engine catch its breath (or not). By the same token, if the gauge consistently shows that oil is running hotter than optimum, you can fit an oil cooler, change over to a full synthetic and observe the results, or do whatever else you think necessary to bring it down. As they say, information is always a handy thing to have.

The voltmeter monitors the battery voltage, and by extension, the health and load placed on the charging system. Many older/vintage bikes used a charging indicator light to let you know the charging system was functioning properly, if the light came on while you were riding, you could (in theory, at least) reduce as much of the electrical load as possible, and nurse the bike to the nearest safe port. These days charge indicator lights are largely things of the past, so if nothing else adding a voltmeter can warn you of impending electrical doom. For example if the voltmeter normally reads 14.0 volts when you're tooling around at 30 mph, and the needle suddenly drops to 12.0 it's a pretty safe bet that something's amiss in the bikes electrical innards, so end the ride and head for home while you still can.

Just as importantly though, voltmeters allow you to address demands on the electrical system as you ride. For example, at normal cruising speeds, under normal electrical loads, most charging systems put out something around 14.0 volts give or take a few tenths. This provides enough voltage to keep the battery fully charged and perhaps operates a few minor electrical accessories like spotlights or a GPS without problems.

However, as you start adding electrical accessories, such as a heated riding suits and grips (or cocktail blenders) you can overtax the charging system to the point where it can't keep the battery charged. A voltmeter will give you a clear and dead-accurate picture of exactly how much power you're using to run your accessories, so if you've got it all switched on and the voltmeter reads 14.0 volts, or close to it, you're good to go. If the reading drops to 12.0 volts, you might want to turn off the heated grips (at least until the Margaritas are done). Granted, a lot of guys run a lot of electrical accessories without monitoring them with a voltmeter, and do just fine. Unfortunately, just as many overload their charging systems and end up needing a jumpstart after the second coffee break.

Voltmeters are also a handy way to keep tabs on the battery's overall health. For instance, if you switch on the bike one fine day and see the voltmeter reading down around 9 volts, it's a pretty safe bet the bike won't be going anywhere until you either charge or replace the battery. Again, you can never have too much information.

Although we're using a MOTOSENS oil temperature gauge, and voltmeter, the instructions apply to any clamp-on style gauge. Since mounting the oil temperature gauge entails installing an oil temperature sensor in the oil pan, you might want to combine the job with an oil change. If not, make sure you have enough make up oil on hand to replace any that's lost when installing the sensor.

Motosens Gauges
I'm impressed by these little beauties, they were easy to install, look terrific and are easy to read on the move. They're also dead accurate, which is a huge plus in my book when it comes to gauges. Although we went with the classic, analog needle type gauges, the Motosens lineup also includes "Electronic Line," which uses an LED display (shown here). Both types are available with a choice of housing, mounting and face color options and the Classic line has several different lighting options. There's also a "flat" version (bottom) that can be mounted, via double-sided tape to any flat surface. Lastly, the Motosens line up is available in either a metric (C and bar) or standard (F and PSI) calibration.

Because the gauges are designed for universal installation, the instructions, (which were presumably translated from German) were a little dodgy, but nothing that couldn't be puzzled out in a moment or two. Overall, the Motosens gauges are top shelf and best of all convey the type of information you need to keep your bike running at peak performance.


(403) 327-1444
Gauges (ea.) $93.70
Mounting bracket (ea.) $19.90
Oil temperature sensor $26.10

Motosens Instrument Install