+2019 GPX FSE250E Air Cooled Modern MX Mountain Goat

Discussion in 'Thumpers' started by Navin, Feb 5, 2019.

  1. bark sampler

    bark sampler Been here awhile Supporter

    Joined:
    Mar 30, 2008
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    211
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    Middle of Michigan
    Got the bike today. Built it all up and followed some of the suggestions here (Thanks!!). Ktm filter support, spark arrestor, good chain, lots of loctite and grease, etc. etc.

    It was testing out fine and then the rear shock wouldn’t rebound. Seems to have lost all nitrogen in shipping and something is f’d up with the rebound adjuster as well. I’ll have to talk to GPX about what to do. No way I can do the ride like this.

    The forks also seemed to have lots of stiction even after I checked alignment a few times. It’s clear they will loosen up as the wear in.

    Overall, bikes seem to be getting better with that exception. Ran excellent with zero adjustments. Overall looks great.
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    48F1F1C2-8DDF-4904-9B88-4141D2998EB7.jpeg
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  2. tronket

    tronket Adventurer

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    Sucks about the shock. Empty gas cylinder happens with KTMs, too.
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  3. bark sampler

    bark sampler Been here awhile Supporter

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    Anyone revalved the forks or shock on these SCZ components?

    I’d be interested in what they have found. The bike came with all the compression adjusters backed out all the way on both ends. From what I have heard and my short test ride they have too much compression even with them 100% out. I’m wondering if the shim stack is way off or there is something off in the adjuster circuits.

    From the diagram it looks like single speed valving which went out of favor in like 1982. It appears that and the weight are the low points on the bike. If I keep it, it would be nice to have a second shock body to try things with.
  4. tronket

    tronket Adventurer

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    It's pretty stiff stock. I haven't messed with valving. But replacing fork oil with Belray 2.5W has softened them up noticeably. Haven't been able to do anything about the shock.
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  5. Navin

    Navin Long timer

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    I’m just ordering up a cap wrench for mine so I can explore the guts. Used as a DS it’s too stiff by a lot. When I had it off road and could hit a few things fast, like big whoops, they were right in the ball park. As a sit down bike or for slower gnarly stuff like rocks I’m sure they are too stiff.

    If you were closer I’d loan you a shock but I’m sure GPX will take care of you. Did it lose all rebound damping or is it going down and binding there? If the latter could the linkage be jammed by something?
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  6. savetosave

    savetosave Adventurer

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    Jun 4, 2007
    Oddometer:
    35

    Give the forks a LONG time to break in. I felt the same way about mine when new, but about the time I decided I would tear into them, they became tolerable. Now at 45 hours and 1100 miles, they feel very good.

    I just rode the Baby Burr dual sport ride last weekend. Rode my 2018 KTM 250 EXC-F Saturday, and the GPX Sunday, and quite frankly the forks on both performed about equally, on some of the highest quality single track in the country.

    If you make changes too soon before they break in, you may find them too soft later on.
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  7. bark sampler

    bark sampler Been here awhile Supporter

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    Middle of Michigan
    Thanks! I’ll miss the ride but GPX has been great on it and is sending a replacement. I can’t ask for more. The rebound went way stiff, and it would stay compressed. That was just riding to a gas station, so never saw trail.

    It would be great to have a second to play with the shim stack. If I do it, I’ll make sure to pass on the details.

    @savetosave, thanks for the confidence. I will wait on the forks until I can pound a few hundred sand whoops and do a fluid change first!
    Navin likes this.
  8. Chadzu

    Chadzu Lost In Space

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    Change the fork oil often. The oil gets nasty pretty quick while they are breaking in. The good thing is that it is easy to change the oil on the OC fork.
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  9. tronket

    tronket Adventurer

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    While we're on the subject. Does anyone know the spec for fluid capacity? I just measured the old oil and refilled to the same level. But I wouldn't be surprised, if the original assembly is way out of spec.
  10. Cascade Adventurer

    Cascade Adventurer All the gear, no skill

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    I shared some fork work details in the thread back on Mar 24 2019.
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  11. tronket

    tronket Adventurer

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    Have you changed fork oil since then?
  12. Cascade Adventurer

    Cascade Adventurer All the gear, no skill

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    I have not changed fork oil since March. Have about 40 hours of single track since then so probably due.
  13. tronket

    tronket Adventurer

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    I rode my FSE for the first time in 2 months today. Been riding other bikes twice a week. Forgot how unbalanced this engine is. Jackhammering aside, I love the power and its delivery. Somehow it's just a perfect match for my body weight, current gearing and current tire. I just go WOT in 2nd up any hill, don't even touch the clutch, and it climbs up without bucking or breaking loose. I just sit on the tank and hold on. A little more power and I would have to feather the clutch to keep the front down. A little less power and it would bog in dips. It's fucking magical.
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  14. savetosave

    savetosave Adventurer

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    Jun 4, 2007
    Oddometer:
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    +1 on above

    Here is a short clip of my FSE working a steep climb out of a creek bed at the Hatfield McCoy trails in West Virginia. The trails were bone dry, and slippery as hell both up and down. The FSE was the only bike in our group to clean this climb on the first try.

    Try to forgive the spodey style of the rider, and listen to the sweet sound of the little 250 motor grabbing traction and working to perfection.

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  15. Navin

    Navin Long timer

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    Unbalanced? Maybe it’s my taller gearing but this engine just purrs in my FSEE? I don’t think I ever rode it beyond the block with the stock cogs but even sitting on the stand idling it’s a pussy cat of a soft motor. My TSE is smoother but that’s an exceptionally smooth engine. The FSE is smoother than any of the KTM RFS bikes I’ve owned, smoother than the 530 and even my new 350. I run the baffle in the muffler too. It’s even quiet.

    Maybe torque check the motor mounts?
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  16. Cascade Adventurer

    Cascade Adventurer All the gear, no skill

    Joined:
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    BB0E331A-9253-480C-A0E3-102A156BA570.jpeg DF8F03D7-1A42-42C1-A50C-A93FC5FF838E.jpeg Did some riding in the Diamond Fork area in Utah. Rode Jocks Canyon trail 019 South to North. More of a cow path with some challenging sections. Mine were the only tire tracks that I saw so doesn’t seem to get much traffic. Did find two skid plates along the trail. Lost the trail near its junction with 018 and went enduro across the Cotton wood creek. Kicked my butt. Bike did great.
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  17. ChiefOshkosh

    ChiefOshkosh Been here awhile

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    First timer on replacing fork oil. This what I got so far reading the forum:
    1. 120MM of fluid for each fork
    2. Belray 2.5w - should soften them up
    3. Fork Wrench size I don't know. Is it a 50mm?
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  18. Navin

    Navin Long timer

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    I have a 50mm wrench for them from RMATV, it should be correct but I haven’t actually tried it yet.

    @ChiefOshkosh
  19. bark sampler

    bark sampler Been here awhile Supporter

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    Yup 50mm. FYI, it looks like Bel-ray quit making both the 2.5wt fork oil and the whole line of HVI suspension fluid. No idea why, but all the sudden both are off their web site too.

    Regarding the shock that came on my bike, I will be tearing into it to see what happened with the rebound locking. It had a decent N2 charge. GPX was super cool and replaced it and is letting me tear into the defective one. Hope to get into shim stack and construction if I can get a break from work.

    @Navin where did you find that horn lead? I think you said under the motor?
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  20. Navin

    Navin Long timer

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    Turned out the one wire missing in the harness according to Gary is the horn. Sorry, I still haven’t gone deeper to open the switch and try to trace a wire or add one.
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