that sounds about normal.
My 2008 250 will be doing 9,000 rpm at an indicated 75 or so.
Staying at illegal speeds for a long time is always a bad idea. But being at 90 -100 will be putting a lot of strain on the little engine and it won't last long with that kind of abuse.
Not that you'll be using the bike much after getting ticketed!

 

that sounds about normal.
My 2008 250 will be doing 9,000 rpm at an indicated 75 or so.
Staying at illegal speeds for a long time is always a bad idea. But being at 90 -100 will be putting a lot of strain on the little engine and it won't last long with that kind of abuse.
Not that you'll be using the bike much after getting ticketed!

Does a Ninja 250 at 90 MPH normally hit the red-line? If not, considering the fact that it would be operating within its designed parameters, how does a 90 MPH workload "abuse" the engine?

 

The older models have a problem with oil being slung up the breather hose that goes up into the air box.

Continous high rpms (9k-up) will tend to cause "low" oil level. Also some oil burning can happen. With this bikes, its always a good idea to check the oil level. Hot or cold engine. It doesnt hold much and it doesnt take much oil loss to lose the engine.

 

The older models have a problem with oil being slung up the breather hose that goes up into the air box.

Continous high rpms (9k-up) will tend to cause "low" oil level. Also some oil burning can happen. With this bikes, its always a good idea to check the oil level. Hot or cold engine. It doesnt hold much and it doesnt take much oil loss to lose the engine.

Said perfectly!

you'll also have a tough time getting up to redline in top gear.
And riding above legal speed limits isn't a "normal parameter" that any bike is designed for. No bike (or car) that is driven fast at high rpms has a chance of lasting as long as one that isn't abused like that.

 

And riding above legal speed limits isn't a "normal parameter" that any bike is designed for.

Eh? Sorry, but that doesn't really make sense. I don't see how you reach the conclusion that motorcycle engineers factor in "legal speed limit" criteria into their motorcycle design decisions.

Anyway, the OP's question wasn't about speed limits but, rather, whether running a bike within a given RPM range would damage the engine.

If I understood the explanation correctly, if you run a bike too close to the red line for too long there would not be enough oil to lubricate the engine properly.

This naturally raises the question of, generally, what percentage of max RPM can one hold for an extended duration without putting undue stress on an engine? Is 50% MAX RPM OK? What about 70%?

 

These little engine redline at 14k (correct?). Holding high rpms for long periods the engine's valves can start to "float" and not close fully so you can end up burning them. Also those two pistons are FLYING. Piston slap will eventually happen. Also oil can only be moved back and forth so fast until it makes it's way past something. So there's your blow by.

 

I max'd out my 2007 Ninja 250 at 111 mph...balls to the wall

 

And riding above legal speed limits isn't a "normal parameter" that any bike is designed for.

um... no...

The ZX ninjas are designed for the track, not a 75 mph speed limit, same can be said for the GSXR's and the R1/R6, 848, 1098, 1198, Daytona 675, RC8, RSV, RSV4, etc, etc, etc.

Jesus people.... the ex250's motor was designed to have the crap spun out of it, 9k all day is not going to hurt it...

 

hell i ride my zx14 at 9K rpm

 

My 250... sold ... LOVED the higher rpms. She ran better and performed much better at 9k and beyond. Below that, she was sluggish.

 

um... no...

The ZX ninjas are designed for the track, not a 75 mph speed limit, same can be said for the GSXR's and the R1/R6, 848, 1098, 1198, Daytona 675, RC8, RSV, RSV4, etc, etc, etc.

Jesus people.... the ex250's motor was designed to have the crap spun out of it, 9k all day is not going to hurt it...

We're talking about extended periods of holding high rpms. At a track you're going through a wide range of rpm's. Slowing down for turns, then speeding up, holding rpms for awhile, then slowing down for next turn, repeat.

Holding a constant high rpm on the highway is different.

 

Holding a constant high rpm on the highway is different.

9k rpm is not "high" for an engine designed to spin up to 14,000 rpm.... 9k is only 64% of it's rpm potential. Start to worry when you're holding 90% or higher of max rpm for extended periods.

 

9k rpm is not "high" for an engine designed to spin up to 14,000 rpm.... 9k is only 64% of it's rpm potential. Start to worry when you're holding 90% or higher of max rpm for extended periods.

9k rpms is a high rpm. I'm not saying getting up to that is bad. I'm saying holding it at that or more gets the oil flung up into the air box. That's all I was stating. Oil up in the air box does not good for the engine.

 

Oil can not get flung up into the airbox. For lack of a better description, the path is a zig-zag and not a straight or arching path. Yes you will get vapors and the vapors will condense into liquid and drain back into the crankcase which is the way it was designed. If you are seeing a lot of liquid oil in your airbox then I suggest you have your engine checked because I think you are suffering from blowby.

 

Oil can not get flung up into the airbox. For lack of a better description, the path is a zig-zag and not a straight or arching path. Yes you will get vapors and the vapors will condense into liquid and drain back into the crankcase which is the way it was designed. If you are seeing a lot of liquid oil in your airbox then I suggest you have your engine checked because I think you are suffering from blowby.

It's common. I've read it over and over. I'm not making it up cause I'm bored. I know the tube is an S shape. I've owned one. I rode one. I worked on one. I've listened to other owners. Crazy. I know.

 

Oil in the airbox is normal. Excessive oil is not. If you get excessive oil in the airbox it's not cause you ran the engine too hard, it's cause there was too much in the crank to begin with, and the pressure is forcing it out.