I just got a EX 250 & I have some other questions about it

Do I really have to follow this break-in period?

Jeb - Sun Jan 16 17:40:50 2006

It has been pointed out that every motorcycle model Kawasaki makes comes with the same, 4000 RPM initial break-in limit sticker on the tach. This really isn't fair, because of gearing. Some bikes do 50 mph or more in top gear at 4000 rpm, while the Ninja/ZZR 250 only does 35 mph, so the bike that does 50 mph in top gear will consume 500 miles sooner. It's really backwards, because EX250 works harder, and would break itself in sooner than, say, a 2-liter, 5k RPM-redline Kawasaki Vulcan. But a mindful break-in is still important.

This is a much-debated topic; some say baby it, some say ride it like you stole it. I'm just going to put up my take on the matter, backed up with a few empirical items.

The fact is that an engine is not fully broken for several thousands of miles. During that period, you have to respect it more than you would a fully broken in engine. That said, the Ninja 250 is probably 95% broken in by 500 miles. And it's probably 90% broken in by 50 miles. Still -- and this is really beside the point of this article -- the engine is not fully broken in until 5000 miles or so, when everything in the engine is completely seated, at which point the engine begins to ever-so-slowly deteriorate (just like you grow until you're 27 years old, then you start to die).

Now, what does "respecting the engine" mean? Generally, it's all about friction and lubrication. Until the engine is run in, there is more friction and less lubrication on critical parts (valves, cams, rings, bearings, etc). These parts must be in good shape for the engine to run efficiently and for long periods of time. Exceed the proper RPMs, and the unworn components will get too hot too fast; you will get hardened rings, scored cylinders, and valves that do not seat correctly. This may not make a huge difference at first, but the increased wear will encourage more advanced wear. Loss of compression, noisy bearings, leaking seals... the list is extensive. But it adds up to less power and shorter engine life span in the long run.

So again: What is the proper respect? What are the proper RPMs? This is a matter of much disagreement. But here is what is usually agreed upon: Do not mess with an engine until it is fully heated up, fully lubricated and ready to be pushed. No one will disagree that multiple, progressive heat cycles are a Good Thing, and that frequent oil changes early can never hurt.

Is there a formula for all this? Not exactly, but here's a good method I would use: make the engine work harder the more you break it in, always keeping the temperature and friction inside in mind. Example: Start the motor, and let it work up to running temperature. Shut down, and cool off completely. Repeat, this time, revving gently, more as the temperature increases. Shut down, cool off. Repeat, this time riding the bike gently. Shut down, change the oil, cool off. Take the bike for ride again, pushing it harder this time; start exploring the upper half of the tach. Never push it until it has warmed up bit. Repeat this cycle several times, each time pushing the motor harder. Try out the redline for a moment here and there; you won't hurt it. Change the oil after another half-dozen runs. Then ride as you would like, but always being more gentle on the machine until it is warmed up and ready for the abuse that Kawasaki's are famous for taking.

Again, this is my take on the issue, how to break in a motor well without breaking it. Do your research, and decide what is best for you and your machine.

How long do I have to wait before switching to synthetic oil?

Duke - Wed May 17 22:46:04 2000

I put about 700 miles on my new rings before changing to synthetic oil, and it began to burn oil like crazy. I was burning nearly a quart every 500 miles! 

I've now switched back to mineral oil, and the oil consumption has slowed way down. I'm at about 1,000 miles and I've only gone through about 3/4 quart. This bike (as is the case with most modern bikes) takes a good long while to get everything seated. I've heard mechanics say to never go to synth oil before 5,000 miles. Won't hurt anything, but you'll wind up burning more oil than you should and parts won't seat completely. I didn't believe them... but 'tiz true.

What is the correct way to apply choke at start-up?

Jeb - Wed Oct 3 14:23:53 2001

Turn ignition key to on position; leave choke off. Press starter button with one finger (no throttle) while gradually turning up the choke. After about three seconds, the choke and carb priming should be adequate to start the engine. Use no more choke than necessary to keep the bike idling.

The gradual application method is better than just turning on the choke and then trying to start it, because the ninja rarely needs full choke to get going. You don't want to give it too much choke, because you risk flooding the engine and encouraging carbon deposits on the valves.

As soon as the engine is in the rhythm (60 seconds or less), ride off; do not idle the engine to warm it up. Keep the revs low, and turn off the choke after you're a few blocks from home. Increase revs as the bike warms up. Choke should only be needed to start a cold engine. It may take some practice to get your starting technique perfected.

My bike jolts forward when I put it in gear after first starting; is this

normal?

Barry - Sat Jul 15 21:42:55 2000

It's "normal" for the bike to jump forward when it has sat for a while. The Ninja 250 has a wet clutch; the same oil that lubes the engine also flows in/around the clutch. If the bike sits for a while, the oil will be forced out from between the clutch plates; the bike jerks when you shift from neutral into first because there is not enough oil between the plates for them to slip.

You can avoid the bike jerking by pulling in the clutch after you start the bike, and then holding in the clutch while the engine warms up. If the oil is cold, pumping the clutch a few times isn't enough. After the bike has been fully broken in (after say at least 5000 miles) you could switch to a synthetic oil; that will lessen the tendency of the bike to jump forward.

Why does my bike take so long to reach normal running

temperature?

Jeb - Sat Jan 27 8:51:48 2001

The EX250's runs cool; the temperature needle will normally stay very close to the cool end of the normal range.

After startup, don't wait for the bike to warm up at idle; this will take too long, waste fuel, and encourage carbon buildup on the valves and spark plugs. Instead, start it up, give the engine a few moments to get into the rhythm, then ride away. Do not apply excessive throttle, or make sudden throttle changes; be smooth. Keep the tacho below 6k until the needle is over the cold mark, and then below 9k until it has reached the normal range (6k and 9k are my limits; you must choose what works best for you). Riding the bike will help it warm up much more quickly.

How far can I go after putting the fuel petcock on "reserve"?

Leon - Sun Aug 6 03:09:34 2000

I usually get 35 to 50 miles on reserve. Reserve should be used frequently. When the petcock is switched from main to reserve, the fuel that goes to the engine comes from a lower part of the tank. The lowest part of the tank is where the water and dirt go if left alone. If the reserve is never used, the level of the water and dirt in the bottom of the tank continually rises. If it gets above the level of the reserve fuel line, it goes into the carbs when the petcock is switched.

Personally I prefer to have a little water and dirt go into my carbs every tank of fuel rather than a lot of it at a time when I'm already in trouble because I let the fuel level get a lot lower than normal.

I think this is one of those messages that needs a disclaimer. Don't do this with your own bike; dirt and water shouldn't be put into the carbs. The correct method is to remove the tank, remove the petcock, then completely drain and rinse the tank. This should be done more frequently if the bike is stored outside where it gets rained on. Dispose of contaminated fuel in accordance with local laws.

What are those tubes hanging down from the bike for?

Jeb - Sat Sep 2 22:14:41 2000

There are a variety of tubes that are bound together at the bottom of the bike. These can include fuel tank overflow, coolant system overflow, carb drainage, and battery vent. These hoses are usually a little longer than necessary when you first get the bike; you can trim them a few inches if you like, but be sure to leave enough slack above the lower routing bracket, and a few centimetres of travel beneath.

Should I use the side prop or centerstand when I park?

Jeb - Tue Nov 13 20:07:33 2001

Use the side prop for everyday parking, and the centerstand for storage and maintenance. The side prop creates a larger tripod than the centerstand does, and is more stable for parking on the street. The centerstand creates a smaller parked footprint, and takes the rear wheel off the ground; this is the better position to have when doing work on the bike, and when parking it at home. Some people do use the centerstand exclusively, though.

Why does my gas tank sometimes whine when I stop?

Jeb - Mon Sep 3 07:57:05 2001

This is due to vapour expansion, and it is normal, especially on warm days. The pressure inside the tank is always changing and restabilising as fuel is pulled out by the carbs, and air gets in to fill the space left. Add the slow process of gasoline vaporization to the mix, and you get a slight whine coming from the vents.