Been there done that....Pretty boring mph speed trial actually.....

The top speed Ive gotten with the 14t sprocket 86mph-8ph=78mph...13t was 88mph-9mph=79mph....With the 14t there wasnt enough road to find more speed..13t just goes dead.......


I was on the expressway and couldnt get it past maybe 9600rpmz....How dare Kawi have a redline thats unreachable and Useless....

....Seems like the last good powerband is around 7100rpmz-8300 rpz....Ive read about the emission gank mod..And cams..But is there any extra ummph after 8500 with the 250klx...

Rocco

 

331 kit+ pumper

 

so, your saying that had you had more road space you could have gone faster on the 14t? So really you could have go to 10,500 rpm if you wanted to?
________
Volcano Vaporizer

 

For staters, it a 250cc 4-cycle engine. I would not expect to hit 70+mph. Secondly, peak torque curve is around 7k and peah horsepower is around 8-8.5k rpms. Its terminal speed, where horsepower is equaled out by drag forces. Redline and rpm limiter is just there for the oopps fellow or hard rev'er at lower speeds.

If you want to hit redline in top-gear, best thing to do is bore up the engine. Make it a 331cc engine. Also change the cam profile to take advantage of more power.

 

The ignition is the limiting factor. The stock ignition goes flat at 8500 RPM. There are no gains in revving the bike too far past this RPM. The option of custom ignition is just too expensive for most mortals.

Took this info from the ADV sit.
"!. Fitted stock KLX300 barrel
2. Kevin Doyle high comp custom ground piston approx 12.7:1 comp
3. custom ground kevin doyle cams still pulling at 13000RPM nasty
4. Stock ignition opened up to 11750RPM (limited the top HP on my bike)
5. tuff rided (special heat treatment) inlet and exhaust valves
6. D.I.D timing chain ( only need if your going to rev the bejezzus out of it all the time
7. K&N air filter
8. Staintune oversize header and muffler (very loud with cams eh)
9. heavy duty barnett clutch springs
10. revalved resprung forks
11. revalved/stroked rear shock
12. shorter 117mm dog bones
13. FCR35 Keihin, but back to stock KLX250 carby for convenience


I ran this bike in and then took it to the dyno shop. It looked stock and the owner laughed when I told him I thought I would get in excess of 30Hp at the wheel. He even went so far as to show me his hp graphs for stock WR250 Yamaha's. Which on his dyno produced 28Hp at the wheel and 24Nm. The first run on my bike pruduced 34 HP from 8500rpm and 27Nm from about 6500RPM. He fell off his chair and I laughed till I cried. He wouldn't believe it (he thought it was a stock bike with a staintune pipe) so he rebooted the computer on the dyno and we re ran it. Same result and it was funny as it was bouncing off the new 11500 redline at about 170Kph. At this point I had to tell him what I had done. Bear in mind this is with the stock KLX250 carby.

I then fitted up the FCR35 Keihin and we ran it again. I struggled to get the jetting right and it was costing a fortune. But with it running rich all the way through the rev range we got 36Hp and a flat 30Nm. Trouble was it was a pig to ride as I couldn't get the carby right. After about ten million scabbed knuckles, swear words and loss of most of my hair. I went back to the stock carby and sacrificed the few extra hp. The reality is that I'm not fast enought to use it anyway. The civility of the stock carb is like a siren to a sailor. Irresisable.

Kevin ran programable ignitions on the Kawasaki Race bikes and they would not flat line like my bike did from 8500 onwards. However the costs for the programable ECU with the required flywheel mods (loss of electric starter) were too high for me in both $$ and convenience. His bike regularly reved to 13000RPM and they were getting about 40Hp from the 250cc version. YEAH BABY. My bike hit 8500RPM and then held almost the same HP till the rev limiter. The Nm dropped away as the revs increased."

"Use the TORQUE Luke". LOL

 

Just so you know...my stock displacement 250 with an OEM carb but extensive mods done by myself ran up to 107 at pocono raceway last weekend.factory carb but my jetting and my exhaust system from other bikes put all together ...it works.sure it takes a bit to get there...but if u can follow your momentum thru the corner you can hammer the sport bikes in the twisties....and that is fun....even though they will walk by u on the infield exit to the big track.either way you catch them on the infield.....supermoto fun ,.......just go ride and have some fun....that's what it's all about.who cares how fast u are....I know i don't

 

I just rejetted my Bill Blue Mikuni TM33 - went from a 140 to a 142.5 main and moved the jet needle back from the richest notch to the middle position. Ran the bike up the road and hit 70MPH easily at 10,500 RPM, and it took less than 1/4 mile to get up to 70. The only other performance mods I have are an HMF slip-on and a UNI air filter (and the air pump removal).

True, there ain't much more bite after about 8500 RPM.

 

The CDI holds it back at 10,500 RPM's. That's all you'll get without a modded CDI. There have been tests done that show there's still more Power to be had above 10,500 RPM's. (Westoz can attest to that). I'd pat yourself on the back for getting it to 10,500. That's a true testimony to a great Setup. I'm completely happy with stock which really doesn't feel good even just over 7,000 Rpm's.

 

With 300cc, pumper carb and 14/47 gearing I feel no need to rev. Just short shift and hold on. I probably rarely ever see over 8000rpm.

 

The timing gets retarded above 8,000 and shut off at 10,500.