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Motorcycle Guide: River Crossing Basics


When out adventuring on your bike, chances are you will come across a river or stream impeding your path. So what are the basic principles you need to be thinking of before you commit to dipping your tyres in the water?


Before you cross, first take this into account:

1. Don't Cross Unless You Have To

While diving in headfirst and showering your mates with a, err, a shower of water is all good fun it is important to make sure that you don't have another option hidden around the corner. Water crossings by motorcycle are full of risk, be it dropping the bike and drowning it, so make sure you are not taking unnecessary risks with your pride and joy.


2. Always Check The Depth

Sure if you can see the bottom it’s likely not going to be a problematic stream to cross but it always pays to check just in case. Even crossings you’ve done a hundred time before can change thanks to the nature of water. Use a stick to probe the water if you are at all doubtful, but the best measure may in fact be to wade in yourself. A damp crotch is always better than a damp cylinder at the end of the day.


3. Know Your Bike

More importantly, know your air intake location. Your bike’s air intake will always have the final say on whether a water crossing is in fact too deep to cross.


For many of us this will be under our seats, but this isn’t always the case so make sure you check your owner’s manual.


If you’re riding with a group of mates, the bike with the lowest air intake that will determine if you attempt a crossing as a group. You don’t want to leave a mate behind do you?


So, just how do you cross water on a bike?

Before you enter the water have a preplanned route in mind, but importantly, you also be prepared to alter this at any time. Fighting your bike mid crossing is a sure recipe for getting wetter than desired, so adaptability is key here.

As you approach the water, you want to be looking for the path of least resistance for the easiest crossing. By this we mean with the straightest route across with as few obstacles such as rocks as possible. Don’t be afraid to dismount to scope out the situation first.


When you enter the water, you want to have enough speed to create a good bow wave ahead of you. This effectively lowers the water level around your air box. With that said, however, you don’t want to be going too fast, 10-15kph is plenty of speed. You are not that guy from YouTube hitting the water at 80kph on the back wheel and blasting your way through the water. If you try it in the backcountry or out in the trail it will go wrong – fact.


You also want your desired riding line to be as straight as possible to increase the chances of success.


Typically, you want to aim at crossing in either first or second gear and importantly you will not change gear mid-stream as any loss of momentum can cause you to fall. Keep the engine revs within the powerband and be prepared to slip the clutch a bit to maintain momentum And prevent stalling. Importantly you don’t want to be spinning the rear wheel as this will waste forward momentum. 


Just as when you are navigating tricky terrain a low centre of gravity will be your friend in a river crossing.

Standing will not only help you to keep your balance and increase your overall agility on the bike, but it’ll also give you to have a good view into the water to spot any obstacles. It’s the best position every time.


If you’re not confident standing, and there’s no shame in that, best keep yourself planted on the seat but if you go this way you will need to try to keep your feet up and out of the water, as putting them down will see your boots act like anchors and pull you off course.


Going For An Unplanned Swim

Even if you’ve done everything above things can still go wrong when you hit the water. You could slip on a rock, stall, or ride into a hidden hole and turn your bike into a submarine.

Whatever the reason, if you go down you want to kill your engine as soon as possible to limit the damage. It can be handy to cover the kill switch when crossing but keep in mind that accidentally hitting it can cause you to fall into the water.


If your bike goes down, do not try to start it if it’s been underwater. Water ingested into the engine can cause it to hydraulic lock which is what happens when your engine can’t compress the water inside the cylinder, meaning you’re going to do some serious internal damage if you try to start it up. This is when carrying a good set of bike tools pays off, as it is very handy to have a spark plug socket and a wrench with you.


If your bike goes swimming in the very least you’ll want to pull the spark plug or plugs out of the engine and remove the air filter (which will be wet and could cause more water to be drawn into the engine) before you crank it over. This will act to flush all the water out of your engine‘s internals without the immense pressure of the combustion cycle.

It is a lot easier said than done, however, and often will require the removal of more than just a spark plug to do properly.


If you and your buddies are up to it, you can stand the bike on its back wheel or even totally invert it (after removing the fuel tank, of course) to add gravity into the mix to help you get the water out faster.


Importantly, take your time to get all the water out and don’t freak out if it takes a while to start back up once you’ve put it all back together.