Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Klx250f starting problem !!!!!!!!

Discussion in 'Technical and Troubleshooting Torque' started by kingy, Nov 19, 2011.

  1. hey guys

    picked up a new toy today.. a 2007 KLX250F with rego and only 428ks on the clock... only cost me 1500 bucks.. long story short bloke had a break up with his misses and needed money for some legal shyt.. my gain i suspose..

    well the bike has been sitting in his garage for 2yrs and hasnt been started.. so i bought it home today bought a new battery and pulled the CARBY out gave it a clean from all the stale fuel . then i pulled the tank off and cleaned that out.. placed a new spark plug in.. start it and just tick tick tick .. it turns over but doesnt fire... i then pulled the air filter out and sprayed DEODERANT into the filter basket and WOW she fires .. as soon as we stop the spray she cuts off... i beginning to the the EXHAUST VALVE is seized open... is there a way to fix this without taking the head apart ??? or is there any otherthing we can try to get this thing working ?????

    cheers guys
    heres a pic anyway
  2. If it fires with deoderant, or any thing flammable for that matter, I'd put money on the carb being the problem. Namely the idle circuit. I'd say that if a valve was stuck, it wouldn't fire at cranking speed. Pull the carb again, do a google search for carb cleaner that you can soak the carb in for an extended period of time rather than just spraying it, and blast all the little galleries with compressed air.
    PS Check if it has one of those stupid vacuum fuel taps. If it has, replace with a standard type one to save yourself any headf#cks in the future
  3. how to do u tell if its got a vacumm on the tap ???? the carb is sparkle clean now. used proper carbie cleaner soaked in that for ages and blew some shit out of the carbie with compressed air... never seen it before but there is like a DIAPHRAM on the carbie.. and unsure how that works... but i did pull it apart and looked new... also the SPARK PLUG doesnt seem to be getting wet
  4. It will have a small vacuum hose coming from somewhere on the inlet manifold to a stub on the fuel tap. You can test the vacuum fuel tap by sucking on the other end of the hose (take it of the manifold -not the tap) and watching if fuel will flow from the tap. Once you've created a vacuum, stick your tongue over the end of the hose to make sure the hose or diaphram in the tap does not have a pinhole or is damaged. It should hold a vacuum indefinately.
  5. will check this out in the morning cheers :)
  6. Definately sounds like it's not getting fuel. Start with the simple stuff first. Pop the fuel line off the carb, turn the tap to the on or reserve position and check for flow. Let it flow for a minute (into a can or container of some description) to make sure you haven't got a breather blockage creating a vacuum in the tank.
    Next, check the fuel is getting into the float bowl. There should be a screw of some description near the bottom of the float bowl that you can loosen 1/2 a turn or so and check for fuel. If no fuel in the bowl, give it a bit of a tap with a screwdriver handle or the like, in case the float needle is stuck in the closed position. If still no dice, then you've got to open her up again, and make sure you haven't done anything really stupid, like installing the float upside down he he he. Or bent the sh!t out of the tang.
    That will do for the moment, as my wife is plying me with beer (I think she wants to take advantage of me), and I fear my replies may start to become incoherant, or my speeeling reeely sh1t, or all of the above.
  7. Have you tried starting it with the choke (en-richer) puled out? its located on the carb.

    If that doesn't work make sure the fuel tap and lines aren't blocked.

    I've got two KLX250E's in the garage (well ones a 300 now) there a bit older but essentially the same.

    Its got a vacuum actuated slide if that's what you mean, the carb should be a CVK, they are kind of annoying.
  8. ^^ This.

    If it's been sitting for a while, you might also check the rubber boots that join the carby(s) to the head for cracks and leaks. As an experiment, spray them (including the ends and the hose clamps and stuff) liberally with WD40 or similar. I'd think 2 years shouldn't be that much of a problem, but ten would be, but you never know.

    Also - while the carb is off - point a torch down the inlet, and up the exhaust, and make sure a family of gerbils or something hasn't taken up residence. Not uncommon for small animals to crawl into places you wouldn't expect and expire there. Check the inlet stuff on the upstream side of the air filter, too.


    What makes you suspect the exhaust valve is sticking?

    "the carb should be a CVK, they are kind of annoying."
    They're a bl00dy lot better than a plain slide carb. It is possible that diaphragm has cracked, though. That'll stop it. Also, if you stripped the carb and reassembled it without knowing what the diaphragm was and how it works, did you leave enough slack in it for the thing to move? Because if you stretched it tight like a drum skin, the thing won't run.

    This seems to be a pretty good pic. As you can see, there's a fair bit of slack in the rubber to allow the slide to go all the way up or down.
  9. Looks like i was a bit slow,
    As far as i know the fuel tap's not a vacuum one, fuel's just gravity feed into the carb

    CVK's better than a normal slide carb but not as good as a pumper carb, mikuni makes one that fits the klx its a good mod to do.
  10. Shouldn't stop it on idle though, just when you get on the throttle.
    I think at least?8-[
  11. Doesnt hold idel at all.. on full throttle when using hairspray she fires.. filter float is right way up and not sticking. just it aint holding idle or at full throttle makes me think its not closed... no animals in air hoses lol.. fuel is leaking from the bowl but cylinder seems dry. poured some fuel into cylinder and it fired . cleaned jets and checked all hoses. cvk is the carbie . that pic is spot on
  12. I'm not entirely sure, to tell the truth. But while you'd like lots of good consistent manifold vacuum at cranking speed, you don't get it, so there isn't a lot of signal for the plunger - so a smallish leak might prevent the thing sitting where it should. I dunno whether they sit in a default 'idle' position without vacuum or not. Never seen inside them while they were working.
  13. OK - if the exhaust valve was sticking there wouldn't be compression, and it wouldn't fire - it'd backfire or after fire or something. If it kicks over, then the problem must be fuel.

    There's still something in that carby, blocking one or more jets.

    Did you take the needle out? Did you note which position it was in? The needle typically has 4 positions.

    Did you remove the idle jet? The intermediate jet? Did you blow through them with your mouth and confirm they're clear? Did you poke something into them - like a piece of wire? (Don't. Not good.)

    Did you strip the emulsion tube(s) and check all the little passages and stuff under them?
  14. That's what the spring is for.
  15. #15 MOS, Nov 19, 2011
    Last edited by a moderator: Jul 13, 2015

    Bad vid but the general idea, they sit in the idle position without vacuum.
  16. Emulsion tube?????????? Everything u said we did.
  17. If that's all the time then your float level is to high.

    Did you try turning the idle adjust screw in a turn or so, or turning the engine over with the throttle half open?

    Your idle could be set so low it wont keep the bike turning over, but on the klxs even if that's the case you can normally still start them with the choke pulled out, it'll just die when you push it back in.
  18. Forget the emulsion tube. It has absolutely nothing to do with idle mixture.
  19. Emulsion tube. ...

    There are two critters in that photo I posted that could be called the 'Main jet.' One is at the top where the needle goes in, and one is at the bottom of that column or pipe. That (bottom) one has a hole in it of a very specific size. Between the two, there is a pipe you can see with (in this case) 3 visible holes in it. I can't see it in this pic, but somewhere there must be an air bleed - or more than one - which bubbles air up into that column structure and causes the fuel to have bubbles in it, an air-fuel pre mixture stage called 'emulsion'. All those little air bleeds have to be clear. The assembly is refered to as the emulsion tube. It looks like (on the carb in the pic) there are actually two of them, so one would be the main and one would be the low speed.

    Not every carb ever made has them, and not on every fuel circuit, but most have something like it.

    "It has absolutely nothing to do with idle mixture." - Well, we're trying to get any kind of mixture at the moment.
    • Like Like x 1