My yz 125 started to bogg down when i put my bike in 3rd gear and i drove it back the next day i went to wash it and i tried to start it. it started but bogged right down till it shut off no matter where the trottle was. so i tried to start it again and kicked it like fifty times and still didnt start i waited about 30 min and i went to start it and it started but bogged down till it shut off again, i took the airfilter off and cleaned it has brand new gas in it and when we took the spark plug out it had spark but were getting a new spark plug anyway what should i do it is all stock

SOURCE: my 01 yz 125 wont start with kick start,n loses power in low rpms

sounds if you picked up some water/dirt in fuel when was low

clean fuel bowl and flush carb by drain port if still ruff then remove carb for cleaning

SOURCE: whilst riding at long periods at high speed my

It sounds like you cooked her. If you are jetted lean, and run it wide open for a long period of time, it melts the ring to the piston.
Do a compression test, remove spark plug, thread in gauge, and hold throttle wide open and kick untill the guage stops climbing (Around ten or so) Less than 100 psi is bad.

SOURCE: yz 125 wont start

gunk in carb jets pluged

SOURCE: Hi there i have an

There are many possibilities for this problem:---bad piston rings, clogged air filter, carb problems, wrong plugs.
First check the spark plug condition, when this problem occurs:-----1) If your spark plug is dry and burnt brown its normal.
2) If your spark plug is whitish it means its to lean.
3) If your spark plug it fouled with black oil over it that means your bike is running to rich. ------------- Try playing with the idle screw or air fuel mixture screw on the side of the carb.
The idle adjustments are easy...........

1.) Adjust your throttle cable free play.
2.) Start bike and warm up.
3.) Once warm, turn idle up a little high at the adjustment and then adjust low speed pilot screw to achieve the highest possible idle w/o turning any other screw.
4.) Adjust the idle screw down to an acceptable level. ------------ There should be the highest idle. That is where the pilot circuit is most efficient and gives the best off idle performance. ---------- click this link below for more help:--- http://technoanswers.blogspot.com/2011/05/spark-plugs-keeps-fouling-on-2003.html ------------- This should help.thanks.helpmech.

SOURCE: Hi i have a 1995 yz250 the bike was fine till one

Hi mate I would be getting someone to check resistance on your stator its a simple test only requires a multimeter but hard to explain on here - From what your saying I think this test could save your headache!
Once stators fail they can be completely unreliable such as allow you to push start but not kick start or allow you to start but as soon as bike warms up fails completely until cold again they even can give false reading when you test to see if spark is at the plug as you see spark but is not strong enough or is sparking at wrong time... I have had bikes come in my work shop where guys have been confident has spark and they have rebuilt and replaced everything you can imagine but all it was the stator failing with not enough resistance..

regards Jamie