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About dvn

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    TT Titanium Member

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    New York
  1. dvn

    2014 YZ250F starting issue

    Thanks for the responses. Joe503, you nailed it. After reading your response, I remembered that my daughter open trailer'd the bike back from Florida in late January and the bike sat untouched for a couple months. It was definitely exposed to some salt. Anyway, we pulled and cleaned all the electrical connections and applied dielectric grease. Started right up and purred like a kitten! Normal idle and throttle response. Thanks Joe. You saved me a lot of trouble shooting.
  2. Doesn't want to start cold without a crack of the throttle. Will initially fire then die. No fast idle. Pops and crackles. Won't idle until it is good and warmed up, then seems to run fine. After initial cold starting and running issue, it will start and run fine all day. Possible issue with the injector? Has anyone cleaned the injector and throttle body? I thought of a tight valve but that would cause this type of condition the opposite of how it's acting now. (start fine cold but not hot) Fuel has been changed. Any thoughts?
  3. dvn

    2015 piston in 2014 YZF?

    I put a '15 piston in my daughter's '14 at around 60 hours. Everything was still in spec on her original parts.
  4. Maybe this old news but I just wanted to pass along some info. Be careful when replacing the front sprocket. Some of the aftermarket sprockets do not fit correctly! I installed a primary drive steel sprocket, tightened it down and it would not turn. Turns out it was bottoming against the case. I’m lucky I didn’t crack the case. The OEM sprocket has a deep recess on the back side to clear the case. The aftermarket sprocket has this recess but it is not deep enough. I informed Rocky Mountain of the issue and they said they would look into it. They were very helpful and overnighted an OEM sprocket to me. Just wanted to give you guys a heads up.
  5. I recently put a top end ('15 piston) in my daughter's '14 @ 65 hours. Everything was still in spec including the ring end gap.
  6. Unfortunately, you're gonna have to pull it apart again and take a look. I'm guessing that the stopper wheel is not sitting in the detent in the shift drum as it should or the shift shaft has slid out of position as yzusmcf had mentioned.
  7. That's exactly what it was. The washer behind the stopper had shifted and was binding. It wouldn't allow the stopper to move freely. Once the shift drum pushed it down, it stayed down. Just another thing to watch for when doing these. Make sure the stopper moves free and the spring returns it as it should. Lesson learned.
  8. Can you elaborate on this a bit? My daughter's bike does not seem to shift properly now. It goes through the gears ok around the yard but shits like crap on the stand. Can't seem to find nuetral and takes several attemts to get into first. Feels like it's not clicking into gear properly.
  9. Nice video. Thanks. I did the stopper and impeller yesterday afternoon. The zip-tie trick worked great. I was surprised and relieved that the stock stopper looked great at 51 hours.
  10. I am also looking forward to seeing your video yzUSMCf. I'll be doing both updates on my daughter's bike this week.
  11. I don't think I would have peace of mind unless I checked it myself.
  12. Couple quotes from the Motorcycle.com review: "Its 77.0 x 53.6mm bore and stroke are the same as the 2014 – and the 2013 for that matter – but the 2015 piston’s ring lands have been change to provide better oil control" "The 2015 YZ250F’s ECU has been recalibrated with new 3D fuel and ignition maps, which are still adjusted based upon gear position. The new maps provide smoother power control at lower rpm. Yamaha claims that they also offer broader mid-range torque and smoother high-rpm overrev, but those changes are less obvious. We can vouch for the 250F’s more linear throttle response off the bottom."
  13. I didn't say that, did I? I asked if anyone has done it.
  14. Has anyone installed a ‘15 piston in their ‘14? Apparently, the piston has been improved. I wonder if the ‘15 ECU maps are available as they have been updated as well.
  15. I thought all the 14's had the old stopper, no? Hope I didn't just order a stopper for nothing. Edit: After looking at the photos above, the new stopper has the thinner, more solid looking wheel on it, correct? If that's the case, my daughter's bike has the old style.