2017 250 EXC-F -- any opinions yet?

Discussion in 'Thumpers' started by KnowFear, Feb 12, 2017.

  1. Retumbo7

    Retumbo7 Engineer

    Joined:
    Mar 12, 2017
    Oddometer:
    421
    Location:
    Reno
    Well that was my best guess haha, hopefully someone else will chime in. Alternatively lemme know if you give up and want to sell it :deal
  2. Guoseph

    Guoseph Been here awhile

    Joined:
    Sep 8, 2011
    Oddometer:
    684
    Location:
    Alameda, California
    Nah, it's kinda sad that it just sits there. I've been waiting forever for a Vortex ECU on back order since December. I dunno if the ECU will solve it though.
    oldschoolsdime92 likes this.
  3. Retumbo7

    Retumbo7 Engineer

    Joined:
    Mar 12, 2017
    Oddometer:
    421
    Location:
    Reno
    I bought my bike in Berkeley and it ran fine in the Bay as stock. Guessing there is something else going on...

    Planning to head up to Mendo again in March if you get it going though!
  4. Guoseph

    Guoseph Been here awhile

    Joined:
    Sep 8, 2011
    Oddometer:
    684
    Location:
    Alameda, California
    Yeah, something is up, I know they choke these bikes up for emissions but no reason that a stock bike can't run at all
  5. bkoz

    bkoz test

    Joined:
    Dec 6, 2008
    Oddometer:
    1,432
    Location:
    Kamloops, BC
    How old is the spark plug?

    Does it fire right up after the shut down?
  6. Guoseph

    Guoseph Been here awhile

    Joined:
    Sep 8, 2011
    Oddometer:
    684
    Location:
    Alameda, California
    1 hr on the entire bike. Sat in someone's garage for a year and a half then sat in mine for 6 months. Finally got around to it due to work and did the fuel filter along w/ the spark plug boot but no fix.

    Does not want to run at all once warmed up. Once cooled down it fires up again on first touch of the starter button.
  7. N8

    N8 Masked pumpkin rider Supporter

    Joined:
    Dec 27, 2012
    Oddometer:
    9,268
    Location:
    Lancaster, PA
    I might be way off but don't I remember reading about some demo mode some bikes accidentally got left in?
  8. Guoseph

    Guoseph Been here awhile

    Joined:
    Sep 8, 2011
    Oddometer:
    684
    Location:
    Alameda, California
    I wasn't aware of this and there seems to be varying reports of what "demo mode" actually does. Supposedly its a security feature at 1.0 hr but I had this problem before the bike officially hit 1 hr of running time, and demo mode supposedly turns the bike into a very large paper weight but my bike still starts and runs...until it gets hot.

    Then I read another post that says its a "demo temp mode" and won't allow the bike to run more than 30 minutes. I guess that might be the case but the bike has about 1hr total now so 30 minutes can't be the total and it's never run for 30 minutes at a time because it always shuts off before hitting 30 mins.
  9. dogsslober

    dogsslober No neck tie, Ti neck

    Joined:
    Feb 10, 2009
    Oddometer:
    5,860
    Location:
    Morgan Hill Ca
    Maybe try starting and let it run with the gas cap off, had buddy who's bike would stop running because his cap wasn't venting and it would stop getting fuel. I had issues with my 350 when new because there were a batch of bad cdi boxes, wonder if you could try a different cdi box
  10. bkoz

    bkoz test

    Joined:
    Dec 6, 2008
    Oddometer:
    1,432
    Location:
    Kamloops, BC
    How long does it run before it shuts down?
  11. Guoseph

    Guoseph Been here awhile

    Joined:
    Sep 8, 2011
    Oddometer:
    684
    Location:
    Alameda, California
    From cold about 5 minutes or so. Once warm it's very short, eventually hot enough that it doesn't want to start at all.
  12. Retumbo7

    Retumbo7 Engineer

    Joined:
    Mar 12, 2017
    Oddometer:
    421
    Location:
    Reno
    Did you check the coolant? It sounds to me like it's either overheating or the increase in temperature is Fing something up in the electrical system.
  13. Guoseph

    Guoseph Been here awhile

    Joined:
    Sep 8, 2011
    Oddometer:
    684
    Location:
    Alameda, California
    I did not, but a friend took a temp gun to it and said it was not getting too hot. Fan circuit has electricity and not hot enough to turn on the fan. I don't remember the temp measurement though.
  14. bkoz

    bkoz test

    Joined:
    Dec 6, 2008
    Oddometer:
    1,432
    Location:
    Kamloops, BC
    I think you are confusing run time vs engine heat. 5 minutes is pretty short. I would put a gauge on the fuel system to rule that out.

    And when you changed the spark plug did you lubricate the spark plug boot with some dielectric or silicone spray before reinstalling? It is possible the boot was torn when you reassembled it.
  15. Guoseph

    Guoseph Been here awhile

    Joined:
    Sep 8, 2011
    Oddometer:
    684
    Location:
    Alameda, California
    Yes it only runs for about 5 minutes, I will check for vapor lock by running w/o gas cap, I have run it with the tank vent hose disconnected but does not solve the problem.

    Spark plug boot was lubricated w/ regular grease not dielectric before installing but I'll yank it again to see if I broke it on install.
  16. bkoz

    bkoz test

    Joined:
    Dec 6, 2008
    Oddometer:
    1,432
    Location:
    Kamloops, BC
    Regular grease will conduct electricity. Look for tiny cracks when inspecting the boot. Will may have to flex the boot to see it.
    Retumbo7 likes this.
  17. dogsslober

    dogsslober No neck tie, Ti neck

    Joined:
    Feb 10, 2009
    Oddometer:
    5,860
    Location:
    Morgan Hill Ca
    I'm down in Morgan Hill, I have a 350 stock cdi box I would let you try to see if its your box. I think my box would work to test on your bike
  18. Retumbo7

    Retumbo7 Engineer

    Joined:
    Mar 12, 2017
    Oddometer:
    421
    Location:
    Reno
    Sounds like we have a winner. Wipe off whatever you put on and re-install properly with dielectric.

    Mikemm likes this.
  19. Guoseph

    Guoseph Been here awhile

    Joined:
    Sep 8, 2011
    Oddometer:
    684
    Location:
    Alameda, California
    Ok will wipe off the bad lube and put on the correct kind then report back.
  20. Guoseph

    Guoseph Been here awhile

    Joined:
    Sep 8, 2011
    Oddometer:
    684
    Location:
    Alameda, California
    Thank you I appreciate it. I have a couple friends w 350's and I will try to swap out with them next if the lube thing doesn't solve it.