SO tired of my kx250F...now it wont start...need assistance

this bike is cursed... ive changed out the entire top end and did valve adjustment. you can read all about it in my last thread last year...so its been sitting for quite awhile. maybe 6 months.

So i started it back beginning of December... the kick start felt like little compression and it was cold so i took it to a hill and bump started it...it didnt run perfect but it ran good enough. so i parked it.

NOW last weekend, i spent 3 hours trying to start it...nothing. I pushed it down steep hill in 2nd and wasgoing so fast and it sounded like it was about to start then the rear would look up and slide down the rest of the hill...

so here are the list of problems..can someone give me a list of things to check for and ill start running through them this weekend? thank you!!

1.) Wont start. gas could be old so ill change it to new gas today. and i guess ill buy another spark plug for it.

2.) its having issues rolling while in gear and with the clutch it...actually its near impossible! i remember this being an issue when it ran, but when im driving, i dont notice any drag...maybe im just gasing through it to notice.

3.) when i started it up in december, it ran rough, backfired, etc...

thanks guys!

Possibly a bent shift fork is why you are having trouble rolling your bike in gear.

Clogged pilot jet. When held up to light it should be a perfect concentric hole with no fuzzy colors, which indicate buildup of dried gas. Most bikes don't roll freely in gear with the clutch pulled.

try cleaning the carb completely...

how do you check for a bent shift fork? it is pretty tough to find neutral

You would have to split the cases and check for a 90 degree angle between the shift forks and the pins they ride on.

Clean the carb pilot jet

2) It´s normal with resistance when rolling the bike in gear with clutch pulled in (engine off).

A motorycles clutch does not fully disengage like a car´s.

3.) when i started it up in december, it ran rough, backfired, etc...

Hope it is not a bottom end issue... More than likely just a gummed up carb.

I had the same problem with my kx250f.

I had reshimmed the valves, rode about 2 rides and then it just would not start, even after an hour of kicking.

The problem with these bikes is the titanium valves, once the coating wears they just start getting eatin really quickly.

Check your valve shimming again, I'm sure it's just your intake valves. Changing them out for kibblewhite stainless valves will eliminate this problem for quite a while as they are a lot more durable, also you'll get more low end, top end loss is barely noticable.

As for your clutch, you probably just need to ajust your clutch cable. but its normal for a bike clutch to drag a little bit.

livetoride21...I say has it right.....I also had the same type of problem....I could kick forever it would never start....I could push start it and it would start....then it got to where push starting it didnt work.....Pulled the top end off and pulled the valves out and one of the exhaust valves was worn so bad it would seat up and would leak down.....I installed the Kibblewhite stainless valves and the springs that goes with it....awesome...runs great......Pull the head off and take the valves out and check them.....good luck......

1.) Wont start. gas could be old so ill change it to new gas today. and i guess ill buy another spark plug for it.

2.) its having issues rolling while in gear and with the clutch it...actually its near impossible! i remember this being an issue when it ran, but when im driving, i dont notice any drag...maybe im just gasing through it to notice.

3.) when i started it up in december, it ran rough, backfired, etc...

1. clean the carb and pop in a new plug. very simple fix

2. no problem, thats very common.

3. jetting is too rich, while you're cleaning you should rejet it while u have the carb torn apart.

Have you checked for spark? If you have read my post

http://www.thumpertalk.com/forum/showthread.php?t=872754

I had spark one week, then none the next. Try a simple test, pull the plug and lay the treaded part on the head or frame and kick it through to see if you have spark (make sure the coil stick is connected :ride:). If you see blue spark good, if not try dissconnecting the kill button.

If you have spark pour some gas down the sparkplug hole (Thimble amount), put the plug in and see if it will hit or at least kick back. You may have to use the hot start lever when you do this.

Keep us informed

Have you checked for spark? If you have read my post

http://www.thumpertalk.com/forum/showthread.php?t=872754

I had spark one week, then none the next. Try a simple test, pull the plug and lay the treaded part on the head or frame and kick it through to see if you have spark (make sure the coil stick is connected :ride:). If you see blue spark good, if not try dissconnecting the kill button.

If you have spark pour some gas down the sparkplug hole (Thimble amount), put the plug in and see if it will hit or at least kick back. You may have to use the hot start lever when you do this.

Keep us informed

yeah i forgot to say check for spark, that should be the first thing you do :ride:

I pushed it down steep hill in 2nd and wasgoing so fast and it sounded like it was about to start then the rear would look up and slide down the rest of the hill...

This is weird for a bike with valve problems. It sounds like the ignition timing is off and if fires too far before TDC on the compression stroke or the crank is going out and it is seizing and then re-cooling. Something is stopping the rotation there. I don't know what part of OK you are in but I am near Seminole at exit 200 off of I-40 and would be willing to help you figure it out if you want to bring it by.

hey guys...well more bad news....so i took the carb off...got it all clean and put a new plug in....and still nothing. even had the airbox out and tried starting fluid and not even a ignition.

this weekend i gotta try some new stuff. let me know if you guys think of anthing else to put on the list. FYI im in tulsa, but i definitely may need to take the bike out to you and see what you think...

1.) Spark

2.) Shims again because i know have about 2 hours after the rebuild top end...so maybe the shims are out again

After months of not being able to start my 04 kx250f it turned out the intake cam gear spun on the camshaft. Take your cams off and make sure the hole on the gear is lined up with the lobe on the cam.

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