Jump to content
Sign in to follow this  

My '11 KX250F won't start

Recommended Posts

I am really having a hard time starting my KX250F. I replaced the spark plug, shimmed the valves (and everything appears to be within tolerance), changed the oil, the air filter is clean, there is plenty of gas, etc... I really am stumped. Any help out there?

Share this post


Link to post
Share on other sites

Anyone have any ideas and willing to help me? I've been plugging away at this and still having issues. Now the kick start lever will move from TDC but it returns to the upward position it won't move at all. Maybe my intake shims are too tight? My feeler gauge slides in at the specified spacing. The C clips on the cams are in the slots on the cams as well as the clamp. Any ideas?

Share this post


Link to post
Share on other sites

The hard starting was taking place before I worked on it. The kick start lever not moving is really puling. I'm thinking I will go back to my original shim size. I have had the cam apart a couple of times and had no problems with the start lever moving.

Share this post


Link to post
Share on other sites

why would you have the cam apart on an 11 all ready, how many hours you put on it cause if there moving on you that bad those valves must be made of shit or you put 200 hours on the bike

Share this post


Link to post
Share on other sites

I bought the bike from a local bike shop (kawasaki dealer). It was used and the previous ownwer traded it for a 450. I know he raced it but not sure how much. Since I've owned it I've ridden it about 70 hours or so. It was becoming such a hard starter that I was having bump start it. It was time for a vavlve adjustment. When I checked them they were way out. I adjusted them and thought they were in spec but after I still couldn't start it I re-checked the gap and found them to be too tight. I backed them up 1 shim size and checked them again and they were within spec. That was when the start lever issue arose. All parts are present and accounted for so nothing dropped in the motor.

It feels like the lever is stopping due to an obstruction. I checked the movement with the cam cover off and it almost seems like the cam lobes are having diffiulty pressing down on the valve caps (or buckets...whichever you prefer) on the intake valves. That's why I was thinking that the shim is too thick (even though my gauge says otherwise). Maybe a broken valve or something? I don't believe the obstruction or stoppage is in the kick start mechanism.

Does this info help at all?

Share this post


Link to post
Share on other sites

ok was the piston at tdc when you checked the valves, did you check and shim the valves step by step from the manual? can it turn over at all? cause it should have alot of compression...... so let me get this straight it wont turn over or wont start and feels like it wont turn over easy, id say re check theme step by step in the manual and make shure the piston is where it is supposed to be at when you check theme, oh and sounds stupid make shure it in neutral, and gt the bike off the stand put it in gear and push the bike back 5 feet and then forward just to make shure there is not a part that broke off lodged in the trans, just simple stuff to check, for future reference dont buy a raced bike as im shure you know that now, but respond back, let me know, i hope some one else chims in here this is weird if its not something stupid ans simple

Edited by roostierooster855

Share this post


Link to post
Share on other sites

Yes, it was at TDC before beginning the valve adjustment, throughout the adjustment, and at the completion of the job. I performed the job as instructed and was very slow and methodical about doing it as well. The motor has plenty of compression.

I will try to clarify what is happening with the kick start lever. After shimming the valves the 1st time (although admittedly too tightly by .5) the kick start lever cycled perfectly. After completing the correction of the shim (reducing the shim size by .5) I pressed down on the lever (while the motor was at TDC) and it went all the way down. When the lever returned to the top position (as if ready for another kick) the lever would not travel down again. It won't move at all as if something is preventing it from any movement. I am not about to try forcing it.

I will also clarify regarding the previous owner's riding of it. The salesman told me that he thought that the guy might have raced it a couple of times but wasn't sure. He did know that the bike had only been ridden a few times. They sold the original owner the bike when it was new and he only had it for a couple of months before trading it.

The riding that I do is trail riding, mostly in the mountains. I have never had the bike on a track, as that is not my thing. I guarantee that the hours I spend riding it are not nearly as hard as track hours.

I'm going to work on it this evening and put in the shims that were originally in it before I shimmed it for the first time. I'm doing this as a process of elimination regarding the shim size. I know the bike kicked just fine with those shims in it. If it kicks, then that problem is solved. If the lever doesn't move then it is obviously something else. I'll update you after I have done that.

Thanks for your suggestions and input.

Share this post


Link to post
Share on other sites

.5 would be .500 thousandths, half inch, .050 is 50 thousandths and .005 is five thousandths, i imagine you mean you moved theme 5 thousandths, ok update me and when your checking theme with feller gauges dont just see if one fits in go biggest you can till it does not fit so you can get the tolerance, valves get tighter as they wear

this might help

http://motocross.transworld.net/1000101783/features/how-to-presented-by-bikebanditcom-adjust-valves/

Share this post


Link to post
Share on other sites

shit sry just realized your talking metric, used to machining, we use standard, 1mm = .0393 thousandths so thats 39 thousandths and 3 tenths of 1 thousandth

Share this post


Link to post
Share on other sites

I knew what you meant and you knew what I meant. Ha.

Anyway, I ran through the shimming again and it's all good. I did work up to the biggest feeler gauge and my spacing is correct. After putting it all back together and turning the crank (using the bolt that is used to find TDC) it seems that something down in the crank seems to be jamming up. It feels like a metal on metal impact (I'm turning the bolt very gently to not damage anything) and all movement completely stops. The spot where it completely stops in when the cam lobes begin to press down on the intake valves.

There is something going on other than my valve gap and the valves themselves. I am not the brightest bulb, but I know when to call it quits and take it into the shop. I am not about to take the whole top end of the motor apart to try to solve this problem.

Share this post


Link to post
Share on other sites

thats weird maybe make a post in the kx forum cause it atleast give an attempt before you take it to a shop cause they will charge you up the wall and they really dont care

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...