An odd issue with my '11 KX250F

[mtnrider601]

I posted this topic in the jetting fuel injection section and somebody suggested I come to this forum. They thought that you all might be able to offer something. I am hoping that is the case. So, here goes.

I bought my bike slightly used during the middle of this summer. I was told by the salesman at the Kawasaki shop that the previous owner only had it for a couple of months and then traded it for a new 450. The dealer shop went through the bike before selling it to me. The salesman said that he thought that the previous owner may have raced it a couple of times but he wasn't sure on that. Since I've owned it I've ridden it about 70 hours. I ride trails (mostly mountain riding) and my riding is certainly not as hard on the bike as track time.

So, my bike was becoming a hard starter and I talked with another guy who rides an 11 and a 12 KX and he said that my valves probably needed to be adjusted. I bought a manual and shimmed the valves as instructed. I also replaced the spark plug. I put everything back together and tried to start the bike but it wouldn't start. I opened it back up and found that the I had inadvertently shimmed them too tightly and corrected the mistake. The spacing is now within spec.

After putting everything back together I tried to start the bike and found that the kick start lever will kick down one time but when it returns back to the top (in the up position to kick again) position it will not move at all. It feels like there is a metal on metal obstruction and I am not about to force it and cause further problems. I am about to take it to the shop but am trying this as a last ditch effort to solve the problem.

Has this ever happened to any of you before? Do you have any ideas or suggestions? If you need additional information I'd be happy to fill in the blanks. Any help would be much appreciated.

[cmstbcchamp07]

I am no expert by any means but have you checked to make sure your timing was spot on before you put it all back togeher it could be your piston hitting your valve(s) if that is possible. I have a xr100 that the valves have hit the piston at the top of the stroke bc the timing was off. Just a thought.

[race250r]

As mentioned above, it sounds like you put it back together out of time. There is an easy way to check. Pull the valve cover and line up the dots on the cam chain sprockets with the cylinder head. With the dots lined up, check to make sure that the cam lobes are pointing outward (exhaust cam facing up and forward; intake cam facing up and backward). Chances are that they are not facing outward, and rather are facing inward. This means you put it together out of time.

All is not lost, though. It is an easy fix, just pull the cam caps and remove the cam chain tensioner to be able to pull the camshafts. Find TDC using the timing marks on the flywheel (2nd mark on the right), you can also use a screw driver through the sparkplug hole to tell that you are at TDC and not BDC. It may take two full rotations to get it at TDC with the timing marks on the flywheel.

Once you find TDC, put the cams back in with the dots lined up on the cylinder head. Put the exhaust cam in first when you do this. Once you get the cams in, put the cam caps back on. Torque them carefully after they are fully seated on the cylinder head (only after they are fully seated to prevent any cracking of the caps). Put the cam chain tensioner back in, torque it to specifications.

Okay, if all was done correctly, it should turn over without issue. Gently turn it over with the kick starter and hopefully you get a complete cycle without metal on metal.

Good job with taking the repair into your own hands, and avoiding a dealership. After some wrench time, these maintenance issues become fairly straight forward. You came to the right place. Good luck and be sure to let us know if you get it figured out.

Chris

[cmstbcchamp07]

I agree with race250r this site is amazing, in fact They helped me get my 07 kx250f running and saved me a ton of money! ? wish you the best of luck man and keep us posted

Edited February 12, 2012 by cmstbcchamp07

[D-K]

[mtnrider601]

Thanks for all of the input guys. I'm guessing you are correct about the cylinder hitting the valves. I figured i was still in time because i marked the cams and the timing chain before removing them when i did the initial shimming on my valves. I will do my best to follow the instructions you've given to see if that fixes the problem.

[mtnrider601]

I'm sitting here poking at the cams with the cover off. It looks exactly like the picture posted on this thread. The dots are lining up perfectly as pictured, the cam lobes are facing in the direction you described Chris, and the flywheel is lined up. It seems I am at TDC.

[mtnrider601]

Posted that last from my phone. Damn auto correct. I'm looking at the came, not poking them.

[drzadam]

first, you mentioned that you shimmed it too tight the first time you tried. After you did that, did you kick it a lot to try to start it or just 20 or 30 times or did you go all gorilla on it? It should be fine even in the gorilla case, shimming to tight just makes the valve stay open a little at TDC. It would not run well or start with the shims super tight, but it should not destroy the motor. So, maybe your kickstarter assembly is in bad shape. There is a ratcheting mechanism in the kickstarter assy. that takes it out of play when the motor spins it, but when you are spinning the motor (as in kicking the lever), it engages. This could be messed up somehow. You need a manual to see what this all looks like, but you would have to take off the right side engine cover (not just the clutch cover, the whole deal so it exposes the kickstart gear and idler gear and the ratchet assy. And also, you need to be careful when putting the cams back in place. If you don't have the cam cap flush and all the way down it could jam the cam up. That could be another place to check. If you put the bike in TDC, compression stroke as the manual says, and then take the tensioner out, the cams should spin with very little torque back and forth. That is one thing to check.

Finally, I would take the cam cover off, and once you are pretty sure it is assembled correctly, turn it over several times using a ratchet and 17mm socket on the rotor nut, turning it counter-clockwise. It will be mildly hard to get through the points where the cams are pushing the valves all the way down, but it should not jam or be excessively hard to turn. If that is all good, it is in the kickstarter or the clutch that the problem is.

[mtnrider601]

Ok, so I'm an idiot! Your screwdriver suggestion worked great Chris. I was at BDC. Kickstart lever works perfectly now. Now i just have to get it started.

Thanks for the help with that.

Brian

[mtnrider601]

The kickstart mechanism seems to be working very well. I know that there is a specific technique to kickstarting these dang 4 strokes and I am working on refining my technique. When I kick it I try to do a medium pressure kick, choke on, no throttle. I finally gave in after about 10 kicks and bump started it. I got it started and let it high idle with the choke on for about a minute. When I turned the choke off the bike died. I've never had it do that before. I am taking my son riding and seeing if maybe I am just not letting it warm up enough before turning off the choke, but this does seem different than it behaved before. Any thoughts on this issue?

I am a pretty mechanically inclined guy and figure things out relatively quickly. Really, I am not as dumb as I may sound.

Thanks again for all of the help guys.

Brian

[drzadam]

you don't sound dumb dude. It is just that these bikes can pretty easily be f-ed up with a simple mistake. Some careful planning and common sense goes a long way. As far as the bike stopping once you take the choke off, I sometimes have to run for a good minute before it will not die when I take it off of choke. I sometimes take it off and then bump the throttle a little until it is warmed up enough to stay lit on its own. Common thing, and it is worse in cold weather on my bike. You were at BDC huh? You will remember your mistake and probably avoid doing it again, and at least you didn't have to spend over a grand to learn from your mistake. have fun with your son

[mtnrider601]

Thanks Adam. The bike ran well but still died about 60% of the time when trying to idle (even when warm). The only thing I can think of is that I may have a valve that is just a tad bit loose. I'm buying a different set of feeler gauges tomorrow. My gauges aren't precise enough and are in .05 increments. I need some that are in .01 increments. My left intake valve felt like it might have been solving something like .02 loose when I checked them but with these gauges it can be tough to tell. Can you think of any other issue that may cause the idle issue? I think I read that a loose valve will idling issues.

[pCp 450]

Idle adjustment might be needed. Since your bike is fuel injected, it should adjust for temperature and oxygen levels. So you shouldn't have any trouble idling in the cold. Regardless of the issue, you should really get the proper gauges and shim to spec.

[mtnrider601]

Ok. Bumping this thread back up to seek guidance again.

My bike continues to be a very hard start and it has been very frustrating. I have gotten the proper feeler gauges and have triple checked my valve clearances. They are right in the middle of the required tolerances (.10-.15 intake and .17-.22 exhaust). The filter is clean. The oil is fresh and has a fresh filter. It has a brand new plug. The fuel is fresh. I tried kicking the bike after doing all of this work and it won't fire. I tried bump starting it and it won't fire either.

I am almost to the point of taking it to a shop. I bought the bike slightly used from a local dealer. I know that I will never again buy another bike or take my bike to them for service because I don't think they ever had their shop go through the bike before they sold it. I really want to figure this out on my own but don't have the expertise, but am a quick learner and persistent.

Any ideas on what the issue could be?

[race250r]

Could it be the Throttle Position Sensor?

[mtnrider601]

I thought about it possibly being the TPS and unplugged it since I couldn't get it to start with it plugged in. I had read that it could be bypassed by unplugging it. Is that true? I still couldn't get it to start with it unplugged and bump starting. Any other possibilities? I certainly haven't ruled out the TPS. Not about to buy a new TPS if that's not the problem. The bike has good compression too. I think i will also pull the electrical adaptors and check that they are all getting good connection.

[mtnrider601]

Anybody have any ideas? How can i check the TPS? Any other thoughts out there? I know there are a bunch of smart bike thus here. Any help is much appreciated.k

[dmm698]

Try kick starting it witht he throttle half way open or just roll it open as your kicking like you would do to start a 2 smoker. When my TPS broke the bike would only start in that manor as if i was starting a two stroke and then it would not idle and it gurgled and burped and ran like absolute crap and would not idle.

[fshum]

when i fall in turns and my bike stalls and loads up it wont start. the kicker is hard to kick. when this happens, I kick it with the throttle opened like and old two smoke and the thing fires right up. 2011 kxf 250 is great. try this to start your bike, just an idea. Have to use your choke for cold starts.