MAN!!! Tough call so far. I'm one that will listen to both sides equally. I gotta say though...I think I'm gonna leave it as is. TROUBLE with that though, I'm constantly flirting with burning it down!!??? Do you guys run your bikes WFO most of the time??????? When my bike hits 65, 70, from there it just goes like a bat!!! So....70-80, is where I'm riding at, and it loves it so far. After 80, it doesn't really build, so I let off, and slowly bring it back up, and keep doing that. That's how I ride it for the most part on the high ways. I'm just flat out curious just how much constant WFO throttle can it take. I can easily tell when it tops out, sure you can too. It doesn't sputter or anything like that, like it's lean or rich, but I push it every time I ride it!!!! I got 5200miles on it now. I change oil 3 times a season, running a Kawi filter and Kawi Semi-synthetic oil. I know there's other filters!!! But....I run Kawi. THINKING I might need a valve job coming up???? Any opinions at the 5000 mile mark?? It seems O.K. Still I'm into tuning that very top end. Been riding my whole life, 250r, banshees, blaters, 2 strokes mainly!! HOW much can this little 4 STROKE beast take??????

 

Maybe it's time for a rocket I guess!!!! ZX6R??? Thanks guys, I'm out.

 

Yup! my wife's ZX6R cruises freeways at 5-6000 rpm in top gear...redline is 16500 rpm!

Yes, yes I do!

 

I think you'd still be able to hit 80, but it might not always be in top gear, especially when you hit a headwind or a hill. I wouldn't worry about over-reving though. The little 250 is tough and can be ridden at WOT all day long. It's got a rev limiter too so there's no risk of exceeding redline in the lower gears.

 

As I read through this thread I’m saying to myself: 80 mph on a KLX250 (looking to go 90), on the highway, are these guys out of their minds? I can’t comprehend those speeds on a 290 lb bike. I came off of a 600 lb bike and on the highway at 75-80 mph the buffering wind from large vehicles would sometimes shake my machine. You all have bigger yams than I! I guess thats why I now only ride off road. Stay safe guys.

 

Why anyone would want to go faster than 60 on a bike that feels like it would blow over if a bird passed by is beyond me. For real!

 

Maybe it's a brain and a desire to continue to using it from an upright position that drives your judgement! There are those who want to be shot from a cannon or fly over the Grand Canyon on a rocking chair too. Oh yea, jump over 30 buses, that's a good one.
80+ and going down hmm, the only reason to stop at the hospital would be to salvage some organs. I'm just sayin......

 

Yes, what you and ol' klx are saying about the intended use of this bike is quite true...especially with the "S" model. Everything from the engine size, gearing, and center of gravity on the S model is somewhat out of whack with top drawer pavement performance. I think CP has the wrong bike for his desired use.

 

As others have indicated, the top speed of an internally stock KLX becomes horsepower limited somewhere in the 80 mph range. Head or tail wind will affect that significantly, as will your degree of tuck, how big your body is as a wind catcher, steepness of up or downhill, etc. As an example, under x-set of conditions, i'll see a change in top speed from mid-70's to lower-80's just by going from sitting upright to tucking my head down to the tank. Changing gearing won't do much to improve your top speed, other than if it's to shift your RPM to peak power at top speed.

I frequently cruise at 65-75 indicated mph in sixth gear during my long commute (50+ miles one way), which is close to WOT for an hour at a shot, depending on wind conditions. Though most of the time I ride about 60-ish. What that means is, my regular cruise RPMs range from ~6000 to 7500 RPM or so, and that's probably 85% of the miles that are on my bike. I've got 12k+ miles on my bike now, one valve needed adjustment at 7400 miles.

I'll agree with everyone: this is not the bike of choice for high speed highway/freeway riding. In normal conditions, about 75-80 is about as fast as it can go. On the other hand, it is a good compromise bike that can do it, with limitations related to power (and stability, for some). For me, this was the most affordable bike that is capable of regular (constant) commuting service, while still allowing fairly strong off-road performance (lightish weight and good suspension), which is where I want the fewest compromises possible. For me, I know there are better compromise bikes out there...but affording one is not really within my reach.

I know everybody has different sensitivities to perceived bike stability, but I have absolutely zero issues with stability of this bike as fast as it will go on pavement (and most of the time on dirt too). Sure it moves around a little, but big deal, it doesn't do anything unexpected - barring mechanical failure or external factors (deer are the biggest issue for me).

Soon after I bought mine, exactly once and only once, with a hellacious tail wind (probably 40 mph or more) and in the tightest tuck possible, I had mine up to an indicated 101 mph (which was probably more like a actual 90+ mph) for a mile or two...the engine was just shy of redline in 6th gear with stock 14/42 gearing, and it absolutely would not go any faster. Even at that speed, the bike didn't do anything to scare me, though I was very scared of the potential for LEO intervention...but I just had to take that golden opportunity to "see what it can do." On the return trip against the headwind, I had to do a maximum tuck just to maintain 65 mph. Big effect, that wind.

 

proper suspension adjustment for weight and speed...stay loose, and don't lean or fight the wind...seated forward and weight down on the saddle...klx will handle the toughest wind and keep stable at speed...

i stay quite relaxed and comfortable through my high speed commutes...seated straight up and no need to tuck to maintain speed...ride mostly with one hand on the throttle and arms very loose...when the blasts of wind hits, i don't want to transfer that to the handlebar or bike...i'm sure i can get a bigger cc bike, but it's lot more fun on a klx...not many 250cc on the highways in california..even a cbr250 or ninja 250 are quite rare to come across on the highways in my commute...people i ride with usually are shocked when i go riding the highways with them...they automatically assume it's a drz400...