2000 KX250 power problem

[Jeeks]

I have a weird accelleration problem.  The bike runs fine but when I'm coming out of a turn in 2nd, I cant seem to up-shift fast enough to get the speed I'm looking for.  The gearing is 13/48, PC 304 silencer, stock pipe.  Rear tire is about 75% good.

[TaKeN]

Bogs down with lack of power ?


Sounds like my KX 125 was ages ago... turned out the piston and cylinder was buggered 


Do a compression test, or take the top end apart ?

[FuriouSly]

I cant seem to up-shift fast enough to get the speed I'm looking for...Jeeks

You saying the bike has power but you over-rev 2nd gear out of a turn and can't shift to 3rd fast enough?

Too lean on jetting.  Rear tire spinning.  Clutch might be slipping.  Probably sprocket set-up though.  13/48 seems a bit bottom end geared (close shifts).  I don't play with gear ratios since I have never had anything but 14/50 on my KX5, but that is for dunes only.

If your bike makes good torque (compression) then look to take advantage of it at the bottom end gears where it is needed.  To tractor out of a turn in second with taller gears you will need some power to do it.  Usually 125/250 riders need to be quick shifters for that jump out of the turns.  Look into race gas if you don't run in sanctioned races.  You can add some higher compression and bottom end power for that purpose.

Sly

[Jeeks]

It doesn't bog down.  It seems to rev up faster than the bike moves.  If I clutch out of a turn in say...2nd, I'll shift thru 3rd, then 4th very quickly to get some speed up to hit 5th.   It feels like the tire isn't hooking up, just spinning.  As I said earlier, it's about 75% good, Dunlop 752.

I remember my 98 KX 250.  In the same situation, I could clutch out of a turn in 2nd, hit 3rd for a little then 4th.

With the 2000, I'm constantly up-shifting to get some speed.

The clutch doesn't seem to be slipping, if anything I think it may be traction.

The bike is new to me so I don't know if anything was done to the engine.  If I am experiencing loss of traction, what would you reccomend?  Tire? Sprockets?

[The Flyin Hawaiian]

Heres a quick way to check if the clutch is slipping. Get out on a dirt road at a low speed and low revs, put it in 5th and roll the throttle on quickly. If the revs come up quickly and the tire is not spinning, your clutch is toast or misadjusted. How much freeplay do you have at the clutch lever? If there is not enough, the clutch can slip.

[Jeeks]

The clutch is fine and adjusted properly.  I'll have someone check the rear wheel next time I go out.

[KXcam22]

You might want to verify your compression. I have been on some low compression (read worn) bikes that reved really fast but just didn't go anywhere. Cam.

[Jeeks]

Well, it seems to be a traction problem.  I replaced the PC silencer with a stock one and that seemed to give a little more power through out the RPM range.  In a month or so, I plan on a top end, reeds and see if anyone messed around with the jetting.