2017 250 EXC-F -- any opinions yet?

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

  1. Guoseph

    Guoseph Been here awhile

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    Ok sit rep.

    Removed spark plug boot and cleaned off the old grease, including grease inside the hole to the best of my ability. Luckily boot does not appear broken.

    Reinstalled with dielectric grease and bike fires up easily at ambient temp 52F. Runs approximately 8 minutes at idle, radiators hot to touch but not finger burning hot. Bike cuts off and won't start with or without throttle input. Remove gas cap to try again and no change.

    Left bike alone for a few hours to allow it to cool completely and then it fires up immediately on pressing start button and runs 7 minutes before stumbling and shutting off, was able to restart several times but bike runs poorly a minute or so at a time until stumbling and shutting off. Total run time approximately 11 minutes including restarts.

    Could just be me but the valves seemed louder when warmed up. But I am unfamiliar with this motor so no baseline of what "normal" valves sound like. Will wait for bike to cool down and check valves.

    Appreciate any other input
  2. dogsslober

    dogsslober No neck tie, Ti neck

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    I would get a Tacomoto pressure gauge and check to see what the fuel pressure is doing during that 11 min, maybe the fuel pump is wonky and heating up to the point of seizing till it cools off.
    guessing is all I got
  3. bighuckpunk

    bighuckpunk Make a wish

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    Are you still getting a spark when the motor is not working at minute 8?
    You can use a second spark plug to check and not have to remove the spark plug in your engine.
    Back in the 1970's I would have guessed you have a bad capacitor.
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  4. oldschoolsdime92

    oldschoolsdime92 Been here awhile

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    I ordered my Vortex ECU from taco moto, around December 27th, and had it within a week. Where did you order from?
  5. Guoseph

    Guoseph Been here awhile

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    Slavens, I guess they have lower priority...
  6. Retumbo7

    Retumbo7 Engineer

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    I continue to use this bike for purposes outside of its intended use, and it continues to impress me.

    I slimmed down my on-bike luggage somewhat after purchasing the best moto backpack ever, and decided to test my subframe reinforcement through some medium whoops with overwhelming success. Didn't get pics (patiently waiting for my Skydio 2 drone!), but note how the bike is still in one piece at my Friday lunch spot:

    [​IMG]

    Saturday I spent some time hacking together some new passenger pegs using the Axis mount combined with some Ebay Hayabusa Pegs. Took a few hours of measuring, uninstalling, angle grinding, and reinstalling to take out a lot of "superfluous" material, but GF found them far superior to both the little aluminum cylinders that come with the Axis and also better than Rescue Pegs we have used in the past. When folded up they are barely noticeable on the back of my boots while standing in attack position, so I'm going to call it a success.

    [​IMG]

    Next up is wiring in some heated grips and fixing the "design oversights" of the moto-minded supermount.
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  7. bkoz

    bkoz test

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    Another good rip on the EXCF. Don't mind the skiff of snow in the pics. At lower elevations it was hero dirt under the snow. The trails in this area a flowing with good berms. It was a lot a fun to drop into a corner and have the traction to get that front wheel just off the ground while on the gas on the exit.

    I went much stiffer on the low speed on the front forks, much better but I believe a revalve will still be needed. I was also getting a little blurbing at around 1/8 throttle and low engine loads. I will have to do a little JD tuning.

    PXL_20210228_205724914.jpg
    PXL_20210228_205806683.PANO.jpg
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  8. Guoseph

    Guoseph Been here awhile

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    Valves check out, 0.15 and 0.13 Exhaust; 0.13 and 0.13 Intake.

    Fresh out of ideas, will send it to a friend to check fuel flow and maybe swap out some electricals w/ his 350.
  9. Retumbo7

    Retumbo7 Engineer

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    I don't want to get too OT, but snow is by far my weakest surface to ride.

    I come from an auto background, and consensus is that depending on snow-type, depth, vehicle weight, and activity, you either want super wide tires at low PSI to "float" on top, or super narrow tires at high-psi to dig down to the surface underneath. My understanding is that with 2 wheels, the only option is the latter? I've also read of people running a chain on their rear, which might make a low psi approach more tenable?

    When I do have to ride on it, I've been trying to treat it like sand, but the reality is I find my bike movements SUPER unpredictable. What is the best approach with respect to body positioning?
  10. bkoz

    bkoz test

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    Ruling out fuel pressure is a good idea.

    Broken or stretched wires in the harness along the head stock is common on these bikes. You may have a issues there.

    You check engine light is off, correct?
  11. bkoz

    bkoz test

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    We are all riding on studs in these pics. I running a old pair of true Swedish Trelleborg tires. These tires are far and away the stiffest tire I have ever seen with super thick sidewalls. Pressure doesn't really matter as far as the ride. I am usually around 12-15psi. Running these numbers seems to helped with tire life.

    The guys running grip studs need to be more careful with pressures. Too little and you start ripping knobs because of excessive flex, too much and you rip knobs because of too much flex. It depends on the tire stiffness.

    I treat deep snow like sand only exaggerated. On the pegs, pushing the tire down into the snow pack, just be prepared to grab traction.

    Other than deep snow a really strong riders triangle attack position is ideal. Feet on the pegs, squeezing the frame, knees bent, butt in the air, elbows up. There is lot's of hidden obstacles in the snow and being in attack lets you soak it up. Riding snow has been great for getting a strong attack position and being stronger on the pegs.
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  12. Guoseph

    Guoseph Been here awhile

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    Check engine light is off.

    I have had bikes w worn wires but harder to imagine that on a brand new bike.
  13. oldschoolsdime92

    oldschoolsdime92 Been here awhile

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    I was going to initially order from Slavens, and when I inquired on stock via Facebook message they said they had one at the time, but were unable to give me any sort of ETA on shipping, so I ended up going taco moto.
  14. Retumbo7

    Retumbo7 Engineer

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    Originally I was skeptical of Taco Moto, the owner being a relative newcomer into the field, but his knowledge of KTMs and bike engineering/mechanics is actually quite good: https://www.youtube.com/c/TACOMOTOCO/videos

    Night and day when you compare to someone like the infamous "KTM and Husky" guy :roflEDIT: who appears to have gone out of business?

    Please report back on your experience!
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  15. Guoseph

    Guoseph Been here awhile

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    I called around and everyone still has the 250 EXCF on backorder. Taco, Tokyo mods, etc.
    oldschoolsdime92 likes this.
  16. Retumbo7

    Retumbo7 Engineer

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    Shouldn't be anything physically different between the Vortex or Athena boxes for the 250 or 350, just a matter of the software. In theory, you should be able to work with a retailer who is also a tuner in order to get one with a 250 map loaded.

    Keep in mind the EXC-F and FE 250s use a different injector from the race 250s and all 350s. Worth having that discussion before ordering something with a custom tune to make sure the tuner knows what they are doing.
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  17. Mikemm

    Mikemm Long timer

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    I read somewhere he just changed the name of the website/company
  18. JHNguyen89

    JHNguyen89 Adventurer

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    Would love to hear your current settings on the JD Tuner. I'm still kinda curious if a GET would be of noticeable improvement
  19. bkoz

    bkoz test

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    I am running the mythical Euro map along with the JD tuner. I can post my settings but I am not sure how useful they will be on the standard US map.

    I believe the GET or Vortex will be an upgrade over the JD tuner. I ran the standard map with the JD tuner first then added the Euro map and got a strong boost in the midrange.
  20. bkoz

    bkoz test

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    Yes, he is still fleecing riders under the bestdualsportbikes moniker.
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