whats wrong with my Kawasaki kdx125?

Question

my kdx 125 is a 94 model it starts first or second kick and idles well. when in nuetral it can be throttled through the whole rev range with no problems, but when riding it it does not like it be ridden slowly it judders but give it full throttle and get up to 60/80 mph and it goes like there is nothing wrong.

Answer 1

oh it's the old fouling spark plug in the kdx 125 trick

Answer 2

Has it been this way since you've had it, or is this a recent change in the way it performs. A 125 2 stroke generally doesn't like to be ridden slowly anyway, but that depends on your definition of slow. I had a 94 KX 250 and had a hard time getting it jetted properly. Take a spark plug that has been used for a while (or even better the entire bike) to a good mechanic and he can tell you if the jetting and plug selection is correct.

Answer 3

Same thing happend to my 04 CR125R. I am 95% shure that you need a leener jet or needle. If you don’t know much about carbs try and fined a manual on your bike. I cant tell you what jet or needle you need because it depends on the altitude that you live at, temperature, fuel mixture, and the bike. Jets and needles are very cheap; $3 or $4 bucks if that. Try this please! The exact thing happened with my bike. If you have more questions post another question and I will look for it.

Answer 4

A dirt bike that old probably needs new piston & rings.
A quick check -
Remove the exhaust pipe and look in the exhaust port with a mirror and flashlight.
Any scoring on the piston or cylinder wall, the top end (cylinder, piston & rings) will have to be rebuilt.
Any discoloration below the rings on the piston and the rings will need to be replaced. Discoloration below the rings mean they are worn out and compression is blowing past them.