Interesting Talk With 2 Mechanics About The Engine

[Ninja Star]

Hello people

I recently talked to two mechanics from different shops and got different views; thought I'd share with you guys and hear your thoughts.

Talked to one guy and he said he did near 200km/h (~125mph) with a passenger on a 250. I told him my bike doesn't go any higher than 9000 rpm in 6th gear (speed tops out at 130-140 km/h). He said I should be shifting late in every gear (around 10k rpm) to get the best out of the bike. He said engines blow if the oil isn't changed regularly. Finally another issue, he said with Ninjettes, is that, usually, starter craps out around 20,000 km.

Then, I talked to another guy who first asked me why I was even pushing the little engine so hard. He said it wasn't good for the engine to sustain high rpms 1.5k away from redline (which is common sense to me). I thought that 250 engines are built strong and can withstand highway speeds and a few minutes of 9-10k rpms. I never used to push my rpms past 8000 until I got the general consensus from my research that its' ok to take it to 10,000 rpm+ once in a while. Now this guy says to not push the bike. But then i think of all the guys and girls who take their ninjettes to the track and really push their bikes lol

Another interesting thing he said was to not use the engine kill switch and that it's for emergencies. It should always be in the ON position and the keys should be used. This also coincides with what the first mechanic said about the starters crapping out. At the MSF course, they taught us to use the engine kill switch when turning off the bike.

The only reason I made this thread is because these guys are both mechanics .

In the end, after all the opinions, I go with what feels right to me which is cruising around 6k rpm since I do mostly city riding. it's just nice to know what the truth really is and where better to ask than experienced Ninjette owners.

[Motofool]

You should have posted this three years ago, when I started commuting in my Ninjette each week day, covering 30 miles of highway at 10500 rpm sustained !!!

Maybe it is not too late after 25K miles of that abuse?

How specifically rpms' damage these engines? Did they say?

[Ninja Star]

Originally Posted by Motofool

You should have posted this three years ago, when I started commuting in my Ninjette each week day, covering 30 miles of highway at 10500 rpm sustained !!!

Maybe it is not too late after 25K miles of that abuse?

How specifically rpms' damage these engines? Did they say?

Haha, no the guy didn't specify. I guess he meant it puts a lot of load on the engine by running it close to its limit at 10k+ rpm.

My logic is that I don't take my car past 4k rpm. And while a bike engine is different from a car engine, it's still an engine.

Then again, the shop that I went to had lots of cruisers and Harley-type bikes. Maybe those bikes are driven differently?

[Tigerpaw]

I wouldn't trust either of them.

- 120 mph with a passenger. Not very likely. Maybe with 2 VERY light people.
- Oil changes are easy to do yourself. What frequency/price was he pushing?
- Starters COULD go at any time. To say that 20,000km is typical, is crazy.

- These engines can run any RPM, all day, every day. If it worries you, just watch the oil level.
- I believe the kill switch is preference. It's a good habit to have, without thinking about it. I personally just use the key, because I don't want to forget, and get a dead battery.


Follow your owner's manual and you will be golden.

[Bones85]

They sound pretty ignorant, but the Ninja 250 FAQ says:

The Ninja 250 motor has a typical lifetime of about 50-60,000 miles. This is highly variable. One rider (Bill Hoddinott) had a motor last 88,000 miles. That motor was taken out by a failing camchain tensioner; Bill reported that the rest of the motor looked fine upon tearing it down. Some have reported needing replacement before 50,000, although this is infrequent and usually due to abuse or severe neglect.

http://faq.ninja250.org/wiki/How_lon...engine_last%3F

That seems a little unsettling to me.

[fishdip]

Originally Posted by Ninja Star

Haha, no the guy didn't specify. I guess he meant it puts a lot of load on the engine by running it close to its limit at 10k+ rpm.

My logic is that I don't take my car past 4k rpm. And while a bike engine is different from a car engine, it's still an engine.

Then again, the shop that I went to had lots of cruisers and Harley-type bikes. Maybe those bikes are driven differently?

it sounds like the same **** ppl say when they are trying to bash the 250.

[choneofakind]

Ehhh, I'm gonna say these guys are taking you for a spin. Sure, you'll wear parts faster if you run 12000 rpm all day. But in the end, no matter how fast or slow your engine is revving, it's going to wear.

Your logic of car engine might be sorta valid, to a point. You take it to 4k... out of what, 6500? 7000? That's 60% roughly. So then, 60% of 14000 is 8400 rpm. You might have trouble with keeping under 8400 rpm on the highway, but if it makes you feel any better, keep it under that for other roads and you'll be fine

it's just nice to know what the truth really is and where better to ask than experienced Ninjette owners.

Right. Because the truth comes from guys who claim that the starter typically goes out after 20,000 km's. (no it doesn't) Many many many of us here have more than 125000 miles on our little ninjettes and I've read of very few cases of bum starter motors. Most of those are crash/rebuild threads anyways. Also consider that these dudes run a shop and likely are trying to create business. Advice given for free by shops to people are not yet customers tends not to be bias-free. Just sayin.

Respectfully, I'm calling BS on what some of those guys said. The only things I've seen that are in line with what I've experienced is that the bike likes being revved up (10k is not needed for every day riding, but hey) and that oil changes are important. Other than that, I'd ignore those dudes and go enjoy a nice ride, shifting wherever it feels natural and not worrying about how I shut the bike off. As long as it stops running without be dropping it, who cares?

PS, if you're actually struggling to get past 9000 rpm in 6th, you need to do some work. Clear the intake of blockages, clean the carbs, lube your chain, make sure your brakes aren't dragging, and make sure the throttle works properly. That's not normal, that's only about 70 mph.

[lgk]

120 mph with two people is bs.
First off the weight is too much and the second thing is aerodynamic drag.

The motor not being able to withstand high rpms is BS.
I have ridden for 10hr trips often with 9-10k rpm pretty much the whole time.

I like the kill switch shutoff better, using the keys kills power to everything.

Oil changes are important, the correct oil needs to be used, with good intervals and level checks.

[Racer x]

125 mph with a passenger. No way no how never going to happen.

I have only seen one starter go bad. The bike had 38000 miles.

Clean oil is good for every engine. And sustained RPm above 10000 will not have any adverse effect.

You need to find different mechanics. First one if full of stories. Second one knows nothing about the 250 ninja.

[allanoue]

F=M*A

Our ninjette engine's mass makes it ok to run at much higher RPMs

[eddiekay]

Sooo, I take ith these mechanics worked at the Honda dealership ?

[jkv45]

Originally Posted by Racer x

125 mph with a passenger. No way no how never going to happen.

I have only seen one starter go bad. The bike had 38000 miles.

Clean oil is good for every engine. And sustained RPm above 10000 will not have any adverse effect.

You need to find different mechanics. First one if full of stories. Second one knows nothing about the 250 ninja.

^ Eric should know about how much abuse they will take, and what will fail when. The engine was designed and tuned by the factory to run at high RPMs.

From the sound of it, both of those mechanics are Old School HD guys with a different perspective. I wouldn't even worry about the life of a starter...

If everything is adjusted properly and the engine is operating within it's normal temp range (that means not cold either) and has adequate clean oil of the proper type, running RPMs consistently at redline isn't going to do any damage. It will increase wear and reduce the lifespan of the engine vs operating at a lower RPM, but that's true with any engine.

Keep everything adjusted properly, run a high quality oil (changed regularly) - and don't sweat it!

[Motofool]

Originally Posted by Ninja Star

Haha, no the guy didn't specify. I guess he meant it puts a lot of load on the engine by running it close to its limit at 10k+ rpm.

My logic is that I don't take my car past 4k rpm. And while a bike engine is different from a car engine, it's still an engine.

Then again, the shop that I went to had lots of cruisers and Harley-type bikes. Maybe those bikes are driven differently?

Sorry, I was just using my bad sarcasm.

I was trying to say that rpms' don't hurt an engine that is properly lubricated and cooled for those rpms'.

Actually, the rpms' are the natural result of the output torque and the resistance or load that the engine has to overcome.

The mass and accelerations of the reciprocating elements determine how fast they can rotate; so, ship engines go around a few times per minute and engines of model airplanes spin at 20K rpm without breaking a sweat.

Now, all this reciprocating and rotational movement happens while all metal parts float on a film of oil that keep them apart at all times.
For that to happen, good oils are needed, as well as reduced gaps between any two moving parts.
Reduced gap is only possible with precision machining and with liquid cooling controlled by a thermostat (which prevent the metal parts from expanding with heat).

This is very important: metal parts of any engine only wear out during the time that they move against another while the film of lubricant is not formed yet.
That time is start-ups only.

The dynamics of that relative movement and the forced flow by the oil pump establish that film, but it takes a few seconds.
The best lubrication happens when the engine is at normal operational temperature.
If temperature goes too high, the oil starts becoming something else and tends to leave areas without protection.
When the gap gets bigger and bigger with wear, it is harder for the film to get steady and much of what the pump supplies goes out at the other end.

At moments when lubrication and temperature are less than ideal, we can brake that film of lubricant if we try to keep the rpms low and the torque high (what is also known as bogging the engine or shifting low).
That happens because rpms' and torque or force over the engine's and transmission's elements are inversely proportional (when one is low the other must be high).
For that reason, it is healthier for the engine to keep the rpms reasonably as high as possible when the bike is overcoming a load (acceleration, hill, etc.).
Never, my friend, be shy of revving your Ninjette, as long as the engine is properly lubricated and loaded.
The longevity argument is a myth: if kept within factory specs, high number of turns per minute cannot have bad effect on the wear of any engine.

At least in theory, an engine that never stops to get started again doesn't wear out.
That tells us that any engine with 50K miles and two start-ups per day is in much better shape than another with the same miles but having been started up six times per day.

That also contradicts the prediction about the starter.

My apologies again.

[Bones85]

Motofool, so you're saying a Ninja 250 engine that is almost always at 10,000+RPM will not wear out any quicker than an engine that rarely exceeds 10,000RPM if all the other conditions (number of start ups, maintenance, etc.) are exactly the same?

[fishdip]

Originally Posted by Bones85

Motofool, so you're saying a Ninja 250 engine that is almost always at 10,000+RPM will not wear out any quicker than an engine that rarely exceeds 10,000RPM if all the other conditions (number of start ups, maintenance, etc.) are exactly the same?

well what leads to it failing. Its all a case by case.

[Boom King]

Originally Posted by Ninja Star

My logic is that I don't take my car past 4k rpm.

That probably helps out your gas mileage But even a car likes a good spanking now and then. In fact, when I owned a Toyota, the owner's manual recommended that at least once a month you take it to an onramp and give it full acceleration. Reason being was that it helps to clear carbon build-up.

[Motofool]

Originally Posted by Bones85

Motofool, so you're saying a Ninja 250 engine that is almost always at 10,000+RPM will not wear out any quicker than an engine that rarely exceeds 10,000RPM if all the other conditions (number of start ups, maintenance, etc.) are exactly the same?

Basically yes, Joe, I do.
I am riding a bike that has proved it to me.

Now, if cheap or contaminated oil is used, and/or cooling is marginal, bad things can happen at those or lower rpms'.

Remember that F x V = Torque x rpm = same for a similar load

If you reduce the rpms' via upshifting, more force or torque has to be applied, which comes from opening the throttle a little more.
Then, more pressure will develop in the combustion chamber and more force the elements of the engine, clutch and transmission will withstand.

The redline is the conservative limit that the manufacturer gives you, beyond which lubrication may start failing due to excessive shear (viscosity forces that oppose the relative movement of the parts and grow higher with their speed), being followed by over-heating and catastrophic failure.

[Ninja Star]

Originally Posted by choneofakind

PS, if you're actually struggling to get past 9000 rpm in 6th, you need to do some work. Clear the intake of blockages, clean the carbs, lube your chain, make sure your brakes aren't dragging, and make sure the throttle works properly. That's not normal, that's only about 70 mph.

Well, that's kind of the reason I went to the mechanic LOL.

I know that top speed according to the ninjette wiki and online resources is around 150. Not as credible as a doctor but still he's more qualified than me to operate on my bike. I looked at some videos about cleaning the carbs and it looks like a lot of work given my level of n00b. I'm a little paranoid with mechanics and their suggestions; so the first guy was dishonest. He said some other things too which made me question him. The second mechanic was honest, but when I told him the bike struggles over 9000 rpm in 6th gear, he asked me why I was even taking it that high haha.

Originally Posted by Motofool

Sorry, I was just using my bad sarcasm.

I was trying to say that rpms' don't hurt an engine that is properly lubricated and cooled for those rpms'.

Actually, the rpms' are the natural result of the output torque and the resistance or load that the engine has to overcome.

The mass and accelerations of the reciprocating elements determine how fast they can rotate; so, ship engines go around a few times per minute and engines of model airplanes spin at 20K rpm without breaking a sweat.

Now, all this reciprocating and rotational movement happens while all metal parts float on a film of oil that keep them apart at all times.
For that to happen, good oils are needed, as well as reduced gaps between any two moving parts.
Reduced gap is only possible with precision machining and with liquid cooling controlled by a thermostat (which prevent the metal parts from expanding with heat).

This is very important: metal parts of any engine only wear out during the time that they move against another while the film of lubricant is not formed yet.
That time is start-ups only.

The dynamics of that relative movement and the forced flow by the oil pump establish that film, but it takes a few seconds.
The best lubrication happens when the engine is at normal operational temperature.
If temperature goes too high, the oil starts becoming something else and tends to leave areas without protection.
When the gap gets bigger and bigger with wear, it is harder for the film to get steady and much of what the pump supplies goes out at the other end.

At moments when lubrication and temperature are less than ideal, we can brake that film of lubricant if we try to keep the rpms low and the torque high (what is also known as bogging the engine or shifting low).
That happens because rpms' and torque or force over the engine's and transmission's elements are inversely proportional (when one is low the other must be high).
For that reason, it is healthier for the engine to keep the rpms reasonably as high as possible when the bike is overcoming a load (acceleration, hill, etc.).
Never, my friend, be shy of revving your Ninjette, as long as the engine is properly lubricated and loaded.
The longevity argument is a myth: if kept within factory specs, high number of turns per minute cannot have bad effect on the wear of any engine.

At least in theory, an engine that never stops to get started again doesn't wear out.
That tells us that any engine with 50K miles and two start-ups per day is in much better shape than another with the same miles but having been started up six times per day.

That also contradicts the prediction about the starter.

My apologies again.

No worries, I knew you were kidding around my man
That is an insightful explanation btw

I goto these guys hoping for atleast half-honest service and they tell me the opposite things. I only put Shell T6 in my ninjette, thanks to your suggestions in previous threads and don't push the bike too hard.

I just thought it was funny and a bit confusing to hear this kind of advice, and given that they're mechanics, one of whom I've been to before, would be semi-reliable. And I actually went to these guys to avoid stealerships and after reading some very good reviews on local motorcycle forums. So much for that.

Caveat Emptor.

[Tigerpaw]

Originally Posted by Bones85

Motofool, so you're saying a Ninja 250 engine that is almost always at 10,000+RPM will not wear out any quicker than an engine that rarely exceeds 10,000RPM if all the other conditions (number of start ups, maintenance, etc.) are exactly the same?

I'll let @Motofool give a well though out answer.

My 2 cents...the high RPM Ninja 250/300 engine(if driven in a similar manner) will not wear out any quicker, if properly lubricated. The engineers designed it that way

These truly are stellar engine/drivetrains. If properly maintained, they will be the absolute LAST of your worries.

[Motofool]

Originally Posted by Ninja Star

........No worries, I knew you were kidding around my man
That is an insightful explanation btw

I goto these guys hoping for atleast half-honest service and they tell me the opposite things. I only put Shell T6 in my ninjette, thanks to your suggestions in previous threads and don't push the bike too hard.

I just thought it was funny and a bit confusing to hear this kind of advice, and given that they're mechanics, one of whom I've been to before, would be semi-reliable. And I actually went to these guys to avoid stealerships and after reading some very good reviews on local motorcycle forums. So much for that.

Caveat Emptor.

That is the oil I have used, since it has been designed for the punishment of Diesel fuel and engines.
It has been excellent so far.

I don't have a reason to think that the mechanics had interest on advising you wrongly; in many cases that is what they have learned from others while working on a particular type of machine.

It is even good advice for the engines that they repair, which are a totally different technology and designed and built for a different purpose.

Your bike is your friend, don't push her too hard and be punctual with her LTC.

[choneofakind]

Originally Posted by Ninja Star

Well, that's kind of the reason I went to the mechanic LOL.

Does it currently run? If so, mix some carb cleaner through with the next tank of gas and see if that loosens anything up at all. That might help a little.

[Ninja Star]

Originally Posted by choneofakind

Does it currently run? If so, mix some carb cleaner through with the next tank of gas and see if that loosens anything up at all. That might help a little.

Yeah, I'm gonna do that at the next fill-up. She had 14,000 km on her when she became mine. I figured getting the carbs cleaned from the mechanic would be a proper solution vs a shorter-term solution of putting in seafoam or carb cleaner.

I'm sure it's something most people on this site relate to... but I'm fallin' in love with her ... so she gets treated to the finest oils and proper maintenance. It's the way she whistles at me every time I'm in the garage...

[jkv45]

Originally Posted by Ninja Star

Hello people

Talked to one guy and he said he did near 200km/h (~125mph) with a passenger on a 250. I told him my bike doesn't go any higher than 9000 rpm in 6th gear (speed tops out at 130-140 km/h). He said I should be shifting late in every gear (around 10k rpm) to get the best out of the bike. He said engines blow if the oil isn't changed regularly.

So the real problem is it won't rev past 9000 in top gear, right?

Will it pull past 9000 in every other gear?

When you are trying to get to top speed, at what RPM are you shifting?

Are you a large person?

What you are experiencing as a problem may not be if you are shifting too low as you are accelerating and the engine is always below it's power peak.

Adding some fuel system cleaner like Techron Concentrate (EDIT: 1oz per gal) is a good idea. What fuel are you using? 87 octane is what you want - without Ethanol is always best.

Ya, that first part is total BS...

[jkv45]

Originally Posted by Motofool

This is very important: metal parts of any engine only wear out during the time that they move against another while the film of lubricant is not formed yet.
That time is start-ups only.

That's true for some engine parts, but not all. Parts that ride on a film of oil like main bearings will wear most at start-up before oil pressure has risen enough to separate them, but other parts that make direct contact with each other like piston rings/cylinder walls and cams/rockers will wear all the time to a certain extent.

Using a superior lubricant will reduce it significantly to the point where the difference is minor, but increasing RPM will always increase wear.

[Ninja Star]

Originally Posted by jkv45

So the real problem is it won't rev past 9000 in top gear, right?

Will it pull past 9000 in every other gear?

When you are trying to get to top speed, at what RPM are you shifting?

Are you a large person?

What you are experiencing as a problem may not be if you are shifting too low as you are accelerating and the engine is always below it's power peak.

Adding some fuel system cleaner like Techron Concentrate is a good idea. What fuel are you using? 87 octane is what you want - without Ethanol is always best.

Ya, that first part is total BS...

It'll pull past 9k in every gear but in the first five gears, the engine will bog between 8-10k rpm and climb smoothly again from 10k onward.

I shifted around 9-10k from 5th the few times.

I'm a small guy (5'8" 135 lbs) and I put the recommended 87 octane. In first gear, that bogging window from 7.5 to 10kish discourages me from high revs and makes me think it's like the carbs vs the whole shifting below the peak issue.

Thanks for the recommendation on try cleaner brand though

[allanoue]

from
http://faq.ninja250.org/wiki/Acceler...changing_gears

The point is dips in acceleration at different RPMs in normal

[DaBlue1]

Originally Posted by Ninja Star

It'll pull past 9k in every gear but in the first five gears, the engine will bog between 8-10k rpm and climb smoothly again from 10k onward.

I shifted around 9-10k from 5th the few times.

I'm a small guy (5'8" 135 lbs) and I put the recommended 87 octane. In first gear, that bogging window from 7.5 to 10kish discourages me from high revs and makes me think it's like the carbs vs the whole shifting below the peak issue.

Thanks for the recommendation on try cleaner brand though

Seems like you've had this same or similar problem since your post in June.
Have you at least looked at your air filter, cleaned or replaced it? What about verifying whether or not the carbs are shimmed or snorkel removed (since you have a slip on)? Tried to locate or purchase the the carb cleaning recomendations?

[quarterliter]

Wait did you say ninjawiki said top speed out of the 250 was 150!? Someone should let racerx know about that! Or if you meant 150 kph it would make more sense haha. Just run some good oil I am running rotella t6 at the moment but it shears quickly even after 500 miles. If you don't start the bike lower the 50 degrees Fahrenheit Rotella 15w40 is a good choice. It is an HDEO meant for big rigs but I follow used oil analysis and other wear tracking things and this oil outperforms and does not shear like the t6. And if you are worried about sustained high rpm don't be. Just make sure the oil is up to temp ( the case on the right side is a decent way to measure) you should not be able to hold your hand on it. Up to temp oil is around 180-230 degrees. I sustain revs 9-13000 for half and hour at least.

[quarterliter]

Plus rotella 15w40 is CHEAP! So you can change it often. Don't go 3000 miles. When and oil change costs 10 bucks why not do it often.

[jkv45]

Originally Posted by Ninja Star

It'll pull past 9k in every gear but in the first five gears, the engine will bog between 8-10k rpm and climb smoothly again from 10k onward.

I shifted around 9-10k from 5th the few times.

I'm a small guy (5'8" 135 lbs) and I put the recommended 87 octane. In first gear, that bogging window from 7.5 to 10kish discourages me from high revs and makes me think it's like the carbs vs the whole shifting below the peak issue.

Thanks for the recommendation on try cleaner brand though

Are you at wide-open-throttle the entire time? It would be odd that it would run poorly around 8000 RPMs but fine at 10,000 RPMs if you were wide-open at both. If you are not, it's possible the mid-range is lean and the needles need shimming.

For the little Ninja to really get going, you need to shift closer to 12,000 RPMs or over. Power is just starting to build around 9000, and shifting at that point will drop the revs down below where you need to be to accelerate strongly.

[Ninja Star]

Originally Posted by DaBlue1

Seems like you've had this same or similar problem since your post in June.
Have you at least looked at your air filter, cleaned or replaced it? What about verifying whether or not the carbs are shimmed or snorkel removed (since you have a slip on)? Tried to locate or purchase the the carb cleaning recomendations?

I went to the mechanic who rode it and he said it ran mint. Still not convinced, I changed the oil and put in a new filter and took it easy on the rpms until I flogged her and I noticed the problem. I'm gonna take her to another mechanic this time. I obviously have a lot to learn about the mechanics of the bike and for now, but due to limited time, I am unable to do as much reading and research as I'd like to and I don't wanna get my hands into something I don't fully understand, so taking her to a mechanic would be the best choice.

Originally Posted by quarterliter

Wait did you say ninjawiki said top speed out of the 250 was 150!? ut I follow used oil analysis and other wear tracking things and this oil outperforms and does not shear like the t6.

Yeah, around 150 km/h; sorry about the confusion! and wow, 500 miles? That's nothing! T6 15w40 it is from now on! Thanks

Originally Posted by jkv45

Are you at wide-open-throttle the entire time? It would be odd that it would run poorly around 8000 RPMs but fine at 10,000 RPMs if you were wide-open at both. If you are not, it's possible the mid-range is lean and the needles need shimming.

For the little Ninja to really get going, you need to shift closer to 12,000 RPMs or over. Power is just starting to build around 9000, and shifting at that point will drop the revs down below where you need to be to accelerate strongly.

I do give her full throttle and she still gives me some trouble in the middle there =\
I'm hoping to have a friend drop her off at the mechanic's during the weekday so he can check it out thoroughly

@allanoue the thing is, I rode my friend's ninjette and the acceleration was way more constant as the revs built up, so there's definitely something with carbs/mixture -_-

[Motofool]

Originally Posted by jkv45

That's true for some engine parts, but not all. Parts that ride on a film of oil like main bearings will wear most at start-up before oil pressure has risen enough to separate them, but other parts that make direct contact with each other like piston rings/cylinder walls and cams/rockers will wear all the time to a certain extent.

Using a superior lubricant will reduce it significantly to the point where the difference is minor, but increasing RPM will always increase wear.

Absolutely, Jay !!!
Every cam and ring, no matter how many in a cylinder, receive lubrication to some degree.
The top ring has a very critical balance between minimum lubrication and maximum sealing capability, all under the worst temperature and pressure conditions.

There is no pressured lubrication there, just a mist from the surrounding rotating parts, so it can become marginal very easily; reason for which the surfaces of many rings and cylinder walls have special anti-friction covering or materials.
Just Google this:
How are piston rings lubricated?

The highest friction coefficients happen between similar materials due to electrons' affinity.
Steel sliding over steel generate huge amounts of heat that will reduce their characteristics of resistance.
For that reason, a microscopic bunch of ball bearings is forced in between both surfaces: clean oil.
Those balls reduce that coefficient of friction many times, with the added bonus of carrying heat away from those metal parts: staying relatively cool those remain strong.
Another good thing that oil does is functioning as a pneumatic seal between high pressure zones (top of pistons) and low pressure zones (crankcase), avoiding combustion and exhaust gases leaking down and contaminating the oil.

Hence, lubrication between rings and cylinders' walls is as desirable as difficult to achieve for all conditions.
The difference between the involved metals creates a safety margin for any brief periods of time when that fine balance fails.
Due to increasing heat and temperature, self-destruction will soon follow if lubrication is not re-established.
When that point is reached, yes, higher rpms' will be more destructive; but that point is way above 10K rpms' for a healthy engine of a Ninja 250.

Metal parts that make direct contact with each other don't last for more than a few miles, if they are that resistant to heat generated by friction.
Cooling systems alone cannot keep the metal parts cool; lubricant is the very important link between the metal and the coolant that can avoid very hot points in any engine.

Heat is the limiting factor that makes internal combustion engines so thermally inefficient (~30%).
Millions have been expend in labs to find more resistant materials (even oval ceramic pistons have been made) and lubricants.

You may be correct, but my experience tells me that engines don't work that way.

[thisisbenji]

I say ride it like you stole it and keep up with the regular maintenance. Used motors are only what $500 anyways?

As far as 9,000 rpm in 6th.... my 250 would hit redline in 6th (not the limiter, although I never tried, but it would get the needle into the red). So your either a lot bigger than me, or there's something wrong with your bike.

[lgk]

Originally Posted by thisisbenji

I say ride it like you stole it and keep up with the regular maintenance. Used motors are only what $500 anyways?

Regular maintenance is all a well designed motor should need.
The difference between idling and and high rpm is oil flow.

The difference in wear between going 6k and 9k for an hour is probably a millionth of a percent.

A rider would cause more damage, with bad shifts than with high rpm.
Poor maintenance will cause more damage than anything else, except maybe a crash.

[DaBlue1]

Originally Posted by Ninja Star

I went to the mechanic who rode it and he said it ran mint. Still not convinced,

If you are still not convinced, examine the bike yourself to verify a few things.
First, start with the snorkel. If it is still installed, chances are your carb needles have not been shimmed. Shimming will help the throttle response between 1/4-3/4 throttle range. If it is removed, chances are you may have a jet kit installed to go along with your exhaust.

What type air filter did you use?
How do the spark plugs look or have they been replaced?

Give Star Tron Fuel Treatment a try. It will help clean the fuel system.

[Ninja Star]

Originally Posted by DaBlue1

If you are still not convinced, examine the bike yourself to verify a few things.
First, start with the snorkel. If it is still installed, chances are your carb needles have not been shimmed. Shimming will help the throttle response between 1/4-3/4 throttle range. If it is removed, chances are you may have a jet kit installed to go along with your exhaust.

What type air filter did you use?
How do the spark plugs look or have they been replaced?

Give Star Tron Fuel Treatment a try. It will help clean the fuel system.

Pretty sure mine is stock. I haven't checked the spark plugs and honestly, would have to look into how to even open up the bike to get to the spark plugs. Apparently, it's easier for first-timers to just take the take off, according to the wiki and I'm not at that level yet :P

I think i'll give the fuel treatment and carb cleaner a try. If she still misbehaves, off to the mechanic we go.

Thanks everyone for your input!

[KawiKid860]

Uhh I can't hit 120mph actual on my 500 with just me... and I'm like 145lbs geared up lol. I hit 127 on the speedo which is probably under 120 actual so... CBR is a different story

Both of my bikes see over 10k on a regular basis too, I mean why have a peaky sport bike if you aren't going to use it like that? They make v twins for a reason

[quarterliter]

Ninja Star the 15w40 is not T6 it is not synthetic. Don't worry about it not being synthetic it does not hinder the performance. If you want to get in a deep oil discussion just let me know but as long as your not riding the bike below 45-50 degrees then the 15w40 will work well. I'm a regular on bobistheoilguy a forum dedicated to finding better oil tracking wear and testing to find the best lubricants. The 15 part is the viscosity when cold. The lower the number the better it flows when cold. But with the lower number more viscosity improvers are needed which increases the shear ability of the oil and so on.