WR250R starting issue

Discussion in 'Thumpers' started by LCarlson, Feb 21, 2020.

  1. LCarlson

    LCarlson n00b

    Joined:
    Jan 20, 2017
    Oddometer:
    6
    Hi all,

    Could use some ideas on a 2008 WR250R starting issue not resolved by ideas in any forum I’ve read.

    Had crashed pretty hard in May but the bike ran fine and I was able to ride it out. Started it a time or two between January and it ran fine for several minutes before I turned it off.

    Started right up in January and ran for about 10-15 seconds before dying. Unable to restart although would intermittently sputter a bit and maybe run for a second.

    Figured bad gas so drained and replaced. No change. New plug, gapped correctly. No change. Replaced fuel pump with a Quantum and regulator off a low mile parts bike. No change. New fuel injector. No change.

    No error codes in diag mode. All sensors test out correctly per the service manual. Pulled injector and see it spray when cranking. Good looking spark. Follow all the EFI checks on the Yamaha tech Youtube video and checks out.

    Previous owner put a PC V on it. I bypassed and no change. Have checked all obvious grounds and seem ok. New battery.

    With all that replaced, if I crank the bike with no throttle, get no hint of it wanting to turn over. If I hold the throttle wide open and crank, it will start to burble after 5-10 seconds. When that happens, I close the throttle and it will typically start and run for a couple of seconds before dying again. Guessing it’s too rich but can’t think of any obvious reason. Not much evidence of that on plug but hasn’t run enough to see if it turns black.

    Only other issue with the bike is it also has an IMS 4.7 gal tank that turns the gas dash light on even with a couple of gallons in it. Wouldn’t think anything in the ECU would be unhappy about that though.

    About to buy an ECU off EBay as I don’t know anybody in Livermore, CA with a WR to swap with to test.

    Appreciate any other ideas on what to check. Thanks!
    #1
  2. Navin

    Navin Long timer

    Joined:
    Sep 22, 2009
    Oddometer:
    29,514
    Side stand kill switch? Clutch lever safety switch?

    Id try spraying a bit of fuel in the throttle body while cranking to see if it runs on that. Then you might at least have a direction to head towards.
    #2
    Bultaco206 likes this.
  3. LCarlson

    LCarlson n00b

    Joined:
    Jan 20, 2017
    Oddometer:
    6
    Thanks for the reply. No change if bypassing the switches and they seem to do what they’re supposed to. Nothing intermittent if jiggling.

    I can get it to keep running on closed throttle by spraying short squirts of starting fluid in the air box every few seconds. Dies with any throttle at all.
    #3
  4. eakins

    eakins Butler Maps

    Joined:
    May 29, 2002
    Oddometer:
    39,025
    Location:
    Fort Collins, Colorado
    Ethanol funking up your fuel pressure regulator?

    Engine needs spark, fuel and compression.

    Pull the plug and look for spark.
    Spray starter fluid in the piston and airbox.
    Does it run? You have a fuel issue, which is often the case.
    #4
    Navin and Fast1 like this.
  5. eakins

    eakins Butler Maps

    Joined:
    May 29, 2002
    Oddometer:
    39,025
    Location:
    Fort Collins, Colorado
    Put an Iridium plug back in there either way.
    #5
  6. Adanac rider

    Adanac rider O.S.T.R. 62 Supporter

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    Location:
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    Is there a lean angle sensor cutout switch ?
    #6
  7. LCarlson

    LCarlson n00b

    Joined:
    Jan 20, 2017
    Oddometer:
    6
    There is and it’s working properly both on the multimeter and cutting the ignition if I tilt it.

    Am running an iridium plug per the other comment. Did find that I had missed checking the air intake pressure sensor and it’s a little out of spec (0.25V) on the low side. Will replace that Sunday and see what happens.
    #7
    Adanac rider likes this.
  8. Navin

    Navin Long timer

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    Sep 22, 2009
    Oddometer:
    29,514
    Im leaning towards a fuel prob now. Sounds like you aren't getting any or enough.
    #8
  9. Adanac rider

    Adanac rider O.S.T.R. 62 Supporter

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    Sounds like a feeling issue , Have you looked at the spark plug cap for cracks or being broken ?
    #9
  10. LCarlson

    LCarlson n00b

    Joined:
    Jan 20, 2017
    Oddometer:
    6
    Pretty much have this down to a low fuel pressure problem now. Injector sprays but not very much. All sensors pass checks and good spark. New injector and air intake sensor. No fuel smell when cranking so know it’s not getting enough gas. Replaced the fuel pump and pressure regulator with one from Quantum which gets the bike closer to starting but won’t stay running. When I look into my IMS tank and turn the key on, I see a pretty good spray of fuel coming out of the back of the regulator and splashing off the housing. Also see it while cranking. That is the back flow side of the regulator so could see some flow. Not sure if I should expect to see a near constant pretty large amount of fuel flow though. Does anybody else see this when priming or cranking? Thanks.
    #10
  11. AppliedMotion

    AppliedMotion Adventurer

    Joined:
    Feb 15, 2013
    Oddometer:
    17
    Location:
    Chanhassen, Minnesota
    Did you figure this out? Curious since I have the same bike. Fortunately, I don't have the same problem. I think Navin is on the right track where some safety mechanism is stopping it.
    #11