Confessions of a Well-Seasoned Motorcycle Mechanic

A lot has changed in the automotive industry since I first started out as an apprentice motorcycle mechanic 35 years ago – I’ve seen and learned a lot. In fact, not a day goes by that I don’t find myself still learning something. In the last 10-15 years motorcycles have been changing at such a fast rate it’s been almost impossible to keep up with it.


This is the technology age and it’s not about to stop. We bought our first motorcycle dyno in 1992, a Dynojet dyno, the first in Australia, and we were laughed at, told it wouldn’t last, “You can’t use dynos for motorcycle tuning”, you’ll be out of business in 3 years, and so it went on and on. Our business has been going 23 years, we are on our third-generation dyno and in the next three to five years we will be upgrading this one again.


Whenever something new comes along, it comes with plenty of knockers, some are afraid of it, do not understand it, or just don’t want change. We hear it all the time, “I wouldn’t take one of those on a big trip – what will I do if it breaks down?” Here’s another “You won’t be fixing that on the side of the road mate”…. chuckle chuckle.


Modern day bikes, like cars, don’t break down generally. If there is a problem, a little red light displays on the dash to let you know and with all the protocols written into the ECU you’ll still be able to continue on and finish your ride in most cases. The only reason you’ll know something is wrong is because the system is smart enough to tell you through the dash. That’s just one of a hundred thousand great things about technology. Given enough time technology has a way of dealing with and answering the critics.

So why so much technology? What drives us all to buy? Because it’s better than what we currently have. It’s more efficient, it’s cleaner & without it – the dirty old petrol engine isn’t looking good. Manufacturers need technology not just to find ways of adjusting to the demands from legislation telling us to clean up the environment, but more importantly improve the product to encourage us, as consumers to continue to dip into our pockets. Besides life would not be much fun if everything stayed the same now would it.


In the past 15 years I’ve seen some massive changes to motorcycles, and although I anticipated it, I didn’t expect the changes to keep coming at the rate they have been. Like it or not computerised motorcycles are here, they are loaded with electronic devices which communicate with each other in applications without a host computer, sharing information with different areas via CAN bus (control area network). Designed for automotive but now used in many other applications. Development started way back in 1983 so it’s not something new, though it is to motorcycles.


So where does this leave the dirty filthy mechanic? No need to adjust valve clearance’s every 6000 km, or change the oil, balance carburettors….no, change spark plugs no way, they are good for at least 20,000 km. Well that grubby little bugger must wash his hands and learn to use a computer, a scan tool, and start thinking analogue to digital and fast.


Here’s an example:- most motorcycles use 12 Volt batteries, however most automotive EFI sensors work on 0-5 volts, so when probing a component should it read 12 volts or something in between 0 and 5 volts? If it’s the latter what should the voltage read, it won’t be 0 and it probably won’t be 5. We need to know what to expect to have any hope. Spare a thought for the battery though, which used to operate start up, the ignition system and a few lights. Now the same battery does that and supplies power for all the electronic systems as well. So our modern motorcycle simply won’t run on 12 volts anymore, it needs a constant 14-14.5 volts.


TPS which means Throttle Position Sensor, operates from about 1- volt to approx. 4.5 volts. So as you open the throttle the TPS senses voltage changes – telling the ECU how much load is on the engine. In the science lab on an oscilloscope, (how many mechanics have one of those?) we can measure this in 2d as the throttle is opened. If there is a problem we can see a sudden voltage drop or spike. We aren’t dealing with straight forward mechanics anymore, but rather in this case simple electronics. Big deal right. Here’s the problem for your poor mechanic, he can’t measure that using a voltmeter and the ECU probably won’t throw a fault code unless it’s really badly worn.


The TPS is still a moving part and over time there is wear, which can cause arcing and may lead to poor idle and rough running symptoms. If the mechanic measures the air fuel ratio it might lead him to believe the engine is running rich and needs a tune up, remapping or whatever.


He is not necessarily wrong he just does not have and probably can’t afford the right tools. I doubt he  had sufficient training to understanding how electronic fuel injection systems and all the associated parts work and relate to the overall package. The manuals don’t tell him this, they just say to replace, but how does he know what to replace if he doesn’t have all the information or properly understands what he is working with or been given the opportunity to learn any of this at trade school. Let us face it, trade schools are not what they use to be.


So next time you have some problems with your modern bike and you’re frustrated, spare a thought for your humble and not so dirty motorcycle mechanic who’s finding it difficult to operate a keyboard and having to go through a massive change in his working environment. Believe me he or she is just as frustrated as you are, if not more so.

5 2 votes
Article Rating
Notify of
Inline Feedbacks
View all comments