Question about 2003 kawasaki KX 125

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2000 Kawasaki KX 125 will not start

My 2000 kx 125 won't kick start it will jump start no probs though. I've changed spark plug air filter, took the carb outstripped it down and cleaned it, took the cylinder head off. the cylinder is clean. I replaced the head gasket. there is compression maybe down slightly but it just will not kick over any ideas. cheers @

Posted by Anonymous on


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Gregg Mahin

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  • kawasaki Master
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Hi, Anonymous and the usual suspects are:
1. Fuel tank empty.
2. The fuel tank has old dead gas.
3. Fuel tank bottom contaminated with ethanol sludge, dirt, water, rust, etc.
4. Fuel supply valve/petcock turned off.
5. Fouled spark plugs.
6. Engine flooded as a result of overuse of the choke.
7. Vacuum hose to the fuel supply valve/petcock disconnected, broken, cracked, or pinched.
8. Fuel valve/petcock or filter clogged.
9. Fuel line to carburetor or throttle body pinched, kinked or blocked.
10. Carburetor float stuck.
11. Fuel injectors clogged.
12. Fuel injectors stuck open.
13. Quick disconnect check ball stuck.
14. Compression below 75 PSI.
15. A stuck-bent-burnt valve.
16. Severely discharged or a damaged battery should have 12.5 volts or more and be able to pass a proper "LOAD" test if necessary, you may have a cursory reading of 12.5 volts or more but little or zero amperage the battery is faulty and must be replaced, AGM batteries fail in this scenario more so than lead-acid batteries.
17. Check battery terminals for damage or corrosion, check the battery cables at "BOTH" ends for loose, corroded, or broken connectors, "INSIDE" and outside the cable harness, perform connector wiggle test and check cables with an ohmmeter if necessary.
18. Loose or corroded wire connection at the coil or plug between ignition sensor and ECM module.
19. Spark plug cables in bad condition and shorting check for spark leakage in the dark, cable connections are loose or connected to the wrong cylinders.
20. Ignition timing incorrect due to a faulty ignition coil, ignition module or MAP, CMP, CKP, O2, TPS, ETP, IAC sensors.
21. Faulty neutral, clutch, kickstand safety switch.
22. Faulty fuel pump or fuse or relay.
23. Faulty or corroded run/stop switch.
24. Tilt sensor needs a reset.
25. Security system not disarming alarm needs a reset.
26. Check for engine trouble codes.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.
KX 125 won start have tried everything
KX 125 Dirt Bike Wont Start HELP
Kawasaki KX125 Service Manual
OEM Parts for Kawasaki
2000 Kawasaki KX125 Owner Manual

Posted on Jul 08, 2018


5 Related Answers


  • 10 Answers

SOURCE: Hard to start when cold, low compression in kick starter

you might of burnt your pistons ring out and now they are not pressing against the edge of the cylinder

Posted on Jun 14, 2009



  • 20 Answers

SOURCE: NSR 125 ran out of two stroke oil and got hot,

Sounds like you have very little compression. Or a reed may be broken.. Make sure reed cage is tight an not sucking air... Id go with the compression test tho..

Posted on Jul 07, 2009

ollie reece

ollie reece-jones

  • 1167 Answers

SOURCE: My 2003 dtr 125 fires but wont run changed stator

try squirting fuel in carb does it fire for a second if this happens

Posted on Oct 12, 2009

Quinn Kessler

  • 85 Answers

SOURCE: it wontt start it has spark

There are only three things that your bike needs to start, Spark, Compression and Fuel, if you say that it has spark and compression then the problem has to be fuel, Make sure that there are no blockages in the line from the tank to the carb, if that is not the problem then you will have to pull the carb and clean out all the ports. I disassemble them as much as possible and empty a can of carb cleaner into a clean coffee can let it soak overnight and then blow out all passages with compressed air and reassemble. You should also pull off your reed cage and check to make sure that your reeds aren't cracked or broke. If your bike was runninng before and you give your carb a good cleaning and the reeds look good and it still doesn't work then you are going to have to look at the other two requirements, your spark should be a bright blue, if not try a spark plug first (you may want to try that before the carb cleaning) next you should get a compression tester and check the compression to make sure it is high enough. Your bike might feel like it has lots of compression but it might be low enough to make it hard to start.

Posted on Dec 09, 2009


Wayne Thomas

  • 301 Answers

SOURCE: my 1992 dr650rse has been stood for 4 years and it

The three required ingredients for combustion are; fuel, compression, and a spark (at the right time). When you cleaned the carb and the jets, did you hold each jet up to a light and actually look through them? The openings in the jets are very small and difficult to clean after than many years of sitting. Same with the carburetor; it needs to be completely disassembled and soaked in carb cleaner, then blown out with compressed air prior to reassembly.
Also, I would check the compression with a gauge. You need to see at least 140 psi on every cylinder, or it is not going to run, no matter what. If the compression is low, adjust the valve tappet clearances and see if that brings it up.
If you come up with the three required ingredients, there's no way it isn't going to run.

Posted on Jan 03, 2010

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3 Answers

I was out riding my kx 125 and the engine just died. It won't start and the engine just backfires. It has plenty of gas and the oil is good too. Checked spark pllug and it was fowled and wet. Cleane

for kx125, that kind of problem i kind of remember my friend just like that too. so clean everything inside . so u have to changes the valves and also the lifter then do the piston pin too,.also chick the rod if in good! that's it for now then when u do that tell me what going on!

Dec 29, 2013 | kawasaki KX 125 Motorcycles

1 Answer

Kx 125 sputtering in high rpms

check and make sure choke is opening all the way,if it is only opening part way could explain why you don't need to use choke at all to start and then at higher rpm's it is not getting enough air causing it to basically choke it self out.

Apr 03, 2013 | 2003 kawasaki KX 125

1 Answer

Hi, i was riding my kx 125 03 yesterday and the dyed on me

Hi,would start by taking the head off and have a look at the top of the piston, if it hasn't got a hole in it.. good....the bottom of your plug may have broken off, this may have damaged your rings so you'll have no compression. You'll have too strip it down further. When you're sorted check your oil/petrol mix and your air screw setting then check your plug regularly for discolouring or oiling up. Go for it, and be methodical.

Mar 12, 2012 | 2003 kawasaki KX 125

1 Answer

Hi i would just like to know if there is a common problem with the kx 65 I took my son riding today and the bike was running good then it stalled on him now it won't run I got it started for 5 sec then...

No common problems to the KX in particular but very common to all race bred 2 strokes is they all require lots of love and attention so clean air and pilot jets regularly clean air filters regularly make adjustments to the fuel air mix screws to suit time of day and altitudes etc regularly and if you ever have problems starting and stalling throw away the spark plug and replace as you no doubt would have fouled it and the plugs never return back well after that no matter how new they may be!
Revisit your fuel oil mix also depending how you ride and where you ride you may want anything from 30:1 mix to 50:1 mix to give reliability (35:1 - 40:1 mix is good place to start?)
I would change spark plug and clean pilot jet in carbi as first steps for this problem then once sarting again do some tests on different fuel mixes (small steps at a time though) to see what works best
good luck regards Jamie

Jun 03, 2011 | 2010 kawasaki KX 65

1 Answer

Bike wont kick start or idle , it will coast

first drain the carby, then set your air mixture screw 2 turns out, from the fully turned in position. The starting proceedure is as follows, when the engine is COLD, turn on fuel, pull on the choke fully, and kick the engine over. DO NOT use any throttle, when the engine is cold, and the choke is on. Remember Choke on, NO throttle.
When warm, no choke, and a little throttle when kicking.

May 12, 2010 | 2003 kawasaki KX 125

1 Answer

My kx 125 was going well then lost power and now can not move kick start at all . how do i tell if the engine is siezed

sounds like it seized! if the kick starter wont go down. take the spark plug out, pour some thin oil down the hole, let it soak overnight, then try moving the kick starter again.

May 09, 2010 | 2005 kawasaki KX 125

1 Answer

I took my kx 80 out for a spin it would go up hills or rev high then i drove down a hill and the back tier jamed i tried to kick it it is also jamed

If it reved realy high then quit then it sounds like you blew up the engine (sucked in air ran lean and seized up) Pull the spark plug and see if there is aluminum on the plug if there is you melted the piston.

Feb 15, 2010 | 2003 kawasaki KX 125

2 Answers

Kx 125 wont start

check air filter and drain old gas out

Feb 27, 2009 | kawasaki Full Suspension Mountain Bike Men

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