The Science of Cleaning Your Motorcycle

If you started motorcycling as long ago as I did, you might be familiar with the term 'greaser'.

This referred to a person rather than a maintenance tool, and was a contemporary and rather derogatory term for a motorcyclist. In those days, the association between motorcycles and layers of thick black grease was quite a close one, though this was something that the Japanese manufacturers helped to break.

However, when you start to dismantle an old motorcycle of any make or geographical origin you will discover that many parts are almost unrecognizable beneath layers of oil, grease, dirt and grit. Naturally, you will need to remove all this to proceed with the rebuild, but what is the best way to do it? The answer is that it depends on which parts you wish to clean and how clean they need to be. So pull up a seat as it might be useful to have a look at a few techniques.

The worst cleaning jobs are generally found in the vicinity of the rear chain, if you have one. Here we are talking about the area around the gearbox sprocket and the underside of the chain guard. The thing is, it is vitally important to keep your chain and chain guard clean. Today's chain oils and chain waxes may be chemically very clever and be 'anti-fling' but this also means that it's all very sticky indeed. Sure, it will stick to the chain, but then so will all the grit and grime from the road. This makes a crunchy sticky paste which can ruin sprockets, chains and the like. Even if the chain is clean, your chainguard will still be covered with the stuff and it will all be ready to fall on the chain again – so it's best to get rid of it when you clean the chain. It's like us having a bath and then getting back into dirty clothes. What's the point?

Second worse is the underside of the sump. An effective way to deal with this is to scrape away the grease with a piece of wood or plastic, and follow this up with a pressure washer. Plain water will do, but you need the nozzle close to the surface for it to be effective. This way, you are not wasting time and resources in trying to emulsify the grease, but just removing it as it is. Bear in mind that the grease will be flung out over the ground and your surroundings, so it might be best to do this somewhere out of the way rather than on your front drive.

If you use a pressure washer on your motorcycle think about the force of the jet and the fact that we are talking about water here. Don't point the jet anywhere near electrical items or wheel bearings (which will get soaked) or the radiator (as the fins are delicate and easily bent). You might also find that any paint which is less than perfect will be at least partially removed so you need to think about the consequences of that first. Also, think about exhausts and levers/cables etc... Often, it's worth having a stash of little plastic bags along with elastic bands and then you can secure any of the more delicate areas of your motorcycle.

One thing which occurred to me a little while ago was that steam cleaning is sometimes offered as a service for really dirty parts of vehicles, and perhaps it would be possible to do it at home – but what might one use? After thinking about kettles and hosepipes or old oil tins on gas rings, it clicked that I already has the very thing I needed: a wallpaper steam stripped. I gave it a go on an old chainguard, using just the end of the hose rather than the wallpaper attachment. This had the advantage that the steam came out as a jet which pushed the grease around. I must say the effect was a little more limited than I had hoped, but I tried this experiment outdoors on an average day so possible in more pleasant conditions it would be more effective. It certainly did soften the grease though, so maybe there is some scope for further experimentation.

A more conventional approach is to use a strong industrial detergent. Most of this stuff is not really meant to be on sale to the public, but there are widely available alternatives. This product contains caustic soda to increase its decreasing power and this does corrode aluminum, though in my experience that does not seem to matter in practice if it is rinsed off reasonably quickly.

You need to work the detergent into the area using a brush, but make sure you wear hand and eye protection. You can get special brushes to use but they do not last long: washing up brushes are cheap and just as effective in my experience. Don't use the one by the kitchen sink though, the other half may just use it as evidence in future divorce proceedings. More general cleaning can be done then on separate parts.