Ya know what grinds my gears? Impatient riders that do not know how to warm up dirt bike the right way. I hate to see a bike go to waste when it could have easily been avoided, and then the owner wonders why their engine blew…
There IS a right and wrong way to start and warm-up your dirt bike, and it isn’t any harder to do it correctly. This article will show you how to properly warm up your engine, whether it’s a 2 or 4 stroke, liquid cooled or air cooled.
How To Warm Up A 2-Stroke Dirt Bike
2-stroke motocross bikes are high-performance race-machines, and should be treated as such. This is not to say that they aren’t reliable, because they often are if you take care of them. Doing routine maintenance and proper warm-up procedures are a must to keep your dirt bike running right (or at all).
How to destroy your engine
The wrong way to warm up a 2-stroke (which I see way too often): Starting up the bike with a cold engine, and once it’s running, repeatedly holding the throttle open for a number of seconds until it’s relatively warm. After the rider revs it out until it won’t “cough” and smoke any more, he/she puts it in gear and goes WOT!……..
First of all, it sickens me to see people (even ones that take decent care of their bikes) do this to their precious machine. What they probably don’t realize is that the piston needs to warm up and “expand” to the size of the cylinder bore.
All metals expand at least to some degree as they hear up. If a part expands too quickly (by revving the snot out of it on first start up) it could cause a cold-seized engine, whether it be a crank bearing or the piston. This may not happen the first time, but if done over and over, it will happen sooner rather than later.
As a result, your bike will be out of commission, and your wallet will be one or three sizes smaller after you repair.
Do THIS, or your dirt bike will break…
Now, the correct way to start a cold 2 stroke engine that will make it last much longer, is as follows…
Before you even turn the gas petcock to “On”, shake the gas tank around so that the 2-stroke oil and gas are mixed properly. Now turn the gas and choke on (depending on air temperature).
Turn the engine over a few times to make sure it has enough lubrication. Without touching or giving it much throttle, give it a good kick to start it up. Leave the choke on for 30-60 seconds after starting it up. During this time you shouldn’t rev the bike much, if at all.
How long does it need to idle for?
Depending what the air temperature is, you should let your dirt bike idle for 1-3 minutes. During this time, I give the throttle a little flick, and it if still bogs or hick-ups then it’s not warm yet. If it revs like normal, then it’s time to put it in gear.
Although, it’s still NOT time to go WOT (wide-open-throttle). The bike won’t be up to full operating temps, so you have to click down into first and putt around on it.
This should be done by going up to about 1/2 throttle for another couple minutes (possibly longer if your bike continues to hesitate upon acceleration). After cruising around for X amount of time until it’s hot, THEN it is time to let ‘er buck!
How To Warm Up A 4-Stroke Dirt Bike
On the flip side, 4-stroke motocross bikes do not require as much warm-up time as a 2-stroke does. This is because four-stroke engines run at higher temps, and if they aren’t getting enough air-flow they will over-heat (more on this in a future article).
Now do as you would a 2-stroke; turning the gas and choke on, give it a couple squirts of gas to prime it (luckily you don’t have gas to mix). Now start the bike, but don’t touch the throttle when kicking or it may kick back and leave you with a bruise.
How long to use choke and idle?
Once your bike is running and idling smoothly, you can flip the choke off. Now, you only have to let it idle for about 30 seconds to a minute; any more than that for a 4-stroke motocross bike and it will start to get too hot. If you want to stay on the safe side, you can cruise around on it for another minute or two, but after that you will want to get it breathing.
If you have a liquid-cooled 4 stroke dirt bike, such as a motocross or enduro bike, letting it idle too long is the most common reason for the head pipe glowing red. The radiators need air to cool them down. The engine is not built to withstand idling for long periods of time before overheating.
How do you treat your possessions?
It really ticks me off when someone doesn’t let their motocross bike warm up before riding it like it’s stolen. Although it’s their dirt bike and they paid for it (hopefully) and can do what they want with it, I hope you are smarter than that.
Do your bike (and wallet) a favor, and take the extra couple minutes to let your high-buck motocross bike properly warm up.
Now that we’ve covered how to warm up your bike, it’s time to learn how to properly ride it. You could learn on your own and make mistakes, or you could start out on the easy path and learn from my mistakes.
To become a good dirt biker rider, you must master the basic skills of throttle, clutch, and balance control. Having a properly setup dirt bike to fit YOUR personal needs is another piece to the puzzle.
Want to become a better rider by taking just a few minutes to read all the basics? Click here to learn proper riding technique for better control.