KLX250(2010, EFI model) Problems with hot startings

Discussion in 'Thumpers' started by Palma JM, Mar 22, 2019.

  1. Palma JM

    Palma JM n00b

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    Hello guys, I'm losing my mind with my KLX250. The previous owner was clearly to harsh on her, and I'm paying all the years of bad handling.
    First of all, she is from 2010, EFI model, doesn't have O2 sensor (has two resistors instead of a standard eliminator kit) and doesn't have side kick sensor (the one who let's the bike to run pass 7500rpm).

    Because of a reason I still don't know, the piston rings got stuck on the piston grooves and the bike lost compression because of it. Some say this happens when the bike gets too hot for a long period of time, but I'm 100% sure it wasn't in the 6 months I had the bike, so I don't know...
    After that I changed the piston rings (piston was good, so I didn't changed it).

    After the repair, she started to have problems when hot starting, usually this is because of valve clearances but mechanic said he checked the valves and they were ok when he assembled the engine.
    This problem doesn't happen always, it seems to me that is more common when tank is almost empty (But can be coincidence).
    When the bike isn't going to start, the FI light flashes when I push start button (ONLY!), if I wait 5 mins, the bike starts normally (and the FI light doesn't flash).

    I don't know what can I do more, can it be valves? Can it be something related to injection? Can it be some electrical shenanigans?

    Sorry for my "Englando", I'm not a native speaker.
    Hope you can help me!
    #1
  2. Palma JM

    Palma JM n00b

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    Can anybody help me?

    Right now, the bike doesn't start at all. When I turn ignition key, the fuel pump makes a strange noise (didn't hapened before) and when I press the start button the engine turns and FI light flashes (ONLY when I press the start button).
    #2
  3. Navin

    Navin Long timer

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    Measure fuel pressure and try it with low fuel which might let your pump overheat. The pump is cooled in the fuel.
    #3
  4. Palma JM

    Palma JM n00b

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    How can I measure the pressure fuel and how the low fuel can affect the cooling of the pump?

    Rith now I think the pump is doing some strange noises and the bike doesn't start at all
    #4
  5. Navin

    Navin Long timer

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    You would need a fuel pressure gage and less fuel in there to cool it... I’ve had bikes that boiled the fuel in the tank and the pumps don’t care for that.

    If you don’t have a shop that can test it I’d throw a new pump and filter in it and try not to run it very low on fuel.
    #5
  6. Palma JM

    Palma JM n00b

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    Is this common to happen if I'm not ridding hard? Like, I don't use this bike for offroad, only smooth drive
    #6
  7. Navin

    Navin Long timer

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    You might just have a 9 year old fuel pump that went bad but running it low on fuel or out of fuel isn’t going to help it’s life expectancy. With what’s chopped up on your bike I’m surprised it ran at all. While you are in there wouldn’t hurt to check the injector spray pattern and probably get it cleaned too.

    I’d really recommend getting it diagnosed in person before throwing parts at it but if you can’t you can’t.
    #7
  8. Palma JM

    Palma JM n00b

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    Yep, I generally try to things my self, but at this point I'm desperate to get this bike running. I might take her to a shop and let's pray I don't have to sell my kidney
    #8
  9. markk53

    markk53 jack of all trades... Super Supporter

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    If you need to replace the pump there may be aftermarket ones available for a fraction of the cost of OEM.

    Seems the Yamaha Zuma 125 suffers from not starting when hot. It is related to the fuel pump. If I pulled in and let the scooter sit for a half hour after riding it wouldn't start, the gas in the tank got hot enough from the engine heat that it shut the pump down. A couple hours later after cooling, it would fire up as if nothing happened.

    There is a company that does aftermarket pumps that fit it, I guess it is the same as the one in the WR250R, which apparently at times had the same issue. In the US it was $60, significantly lower cost than the OEM, but you had to buy the OEM assembly. This pump plugs into the assembly. Check for a company that sells Quantum pumps.
    #9
  10. renogeorge

    renogeorge Let's ride!!

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    Does bike have an in tank filter? Problems like this tend to be filter, pump or plugged injector....
    #10
  11. Palma JM

    Palma JM n00b

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    I will try to check, I'm not sure if there is a tank filter
    #11
  12. Palma JM

    Palma JM n00b

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    Today I was trying to fix this and moved the fuel tank. Before moving the fuel tank the bike didn't started, but after that she started and was woriking normaly. When I shuted it down the problem came back again.
    I checked that when the bike doesn't start there is no spark nor fuel going into the cylinder.

    I think I have the same problem as this guy.
    https://www.kawasakiforums.com/forum/klx-250s-71/klx250-wont-start-no-spark-no-pump-43531/

    I made a video about what happens.
    #12