2017 250 EXC-F -- any opinions yet?

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

  1. Retumbo7

    Retumbo7 Engineer

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    Echo what bkoz says, with the addition that although the JD tuner does not adjust ignition mapping and is overall a cruder fueling solution, I and many others have had decent results with it for ~1/3 the price of the Vortex or GET standalone ECU replacement.

    I would have purchased the Vortex if it was available when I purchased my JD, but now (due to bike depreciation) I would only recommend someone go with one of the costlier options if they were either racing/rallying or committed to the 250 as their main platform (as you appear to be).

    Best of luck, and let us know what you decide!
    oldschoolsdime92 likes this.
  2. bkoz

    bkoz test

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    I don't think it's a huge problem. The updated gear is cheap and relatively easy to replace. If the old gear fails it usually means a full engine rebuild. All this makes it worth while.

    The worst part is KTM knows it's a problem and has not decided to step up are warranty the gears.
    oldschoolsdime92 likes this.
  3. oldschoolsdime92

    oldschoolsdime92 Been here awhile

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    I went ahead and ordered a vortex ECU. I also ordered a pro moto billet end cap to mess with. All from Taco moto. ( I've never dealt with them before, but they provided greatl customer service) The bike is a leftover 2017. I bought it new back in October, and it only has about 10 hours on it at this point. I hope to keep it around for the next 4-5 years.

    Spoke with my local dealer on the gear replacement, and they are willing to do it for a very reasonable cost, so I'm just going to let them do it.
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  4. bkoz

    bkoz test

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    Time for a 200hr refresh

    Before:

    PXL_20201231_004141695.jpg
    The shock needs rebuilding, swingarm bearings need grease and the rads need straightening. At that point its only a few bolts to pull the engine.

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    Only 7% leakdown. A good sign.

    PXL_20210101_154507401.jpg
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  5. bkoz

    bkoz test

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    Very little carbon build up. Nice.

    PXL_20210101_155738174.jpg
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    The bore looks great

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    Except for this:

    PXL_20210101_160649623.jpg
    Same point on the piston

    PXL_20210101_160701329.jpg
    The scoring is a little odd. It is on the minor thrust side (intake) side of the piston. I cannot feel any scoring on the bore. I will clean it up a bit more but I am sure the bore coating is just stained at this point and not damaged.

    Wrist pin and con rod upper bushing look great.

    PXL_20210101_160712814.jpg
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  6. bkoz

    bkoz test

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    The ring end gap was still in spec. As it should be with 7% leakage.

    PXL_20210101_175352627.jpg
    The sweet new Vertex high compression "Racer's Choice" piston next to the OEM

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    The Vertex kit comes with a DLC coated wrist pin

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    Quick piston to bore clearance check. The dial bore gauge is at work.

    PXL_20210101_175738132.jpg
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  7. bkoz

    bkoz test

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    As I had piston kit/gasket kit on hand I figured I will do some inspections on the rest of the engine before continuing. In case parts were needed.

    The clutch is still in pretty good shape. The steels are getting a little color to them. They are all still flat. The hub dampers are still tight but I did replace them fairly recently.

    PXL_20210101_175954113.jpg
    The clutch pack stack height is still well in spec.

    PXL_20210101_180316215.jpg

    I check the oil pump pressure relief valve spring height. In spec.

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    The cam chain is on order (KTM). I made sure it can be removed with the clutch basket still in place. It is tight but doable.

    PXL_20210101_181357943.jpg
  8. bkoz

    bkoz test

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    I pulled the starter down for inspection. Very important on a e-start only bike.

    No wonder I so slow the last ride. Look at all the rocks weighing the bike down. :D

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    Measuring brushes. It is getting close to sourcing a supplier.

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    The commutator before buffing with scotch brite.

    PXL_20210101_182603559.jpg

    After. I also cleaned all the carbon dust from the inside of the starter.

    PXL_20210101_182701387.jpg
    With some manufacturers the notch on the brush designates end of life once worn to that point. My brushes are right here. I also use a light coat of quality moly grease on the starter bushing when assembling.

    PXL_20210101_182823071.jpg

    Does anyone know of a brush spring kit supplier for KTM starters? Slavens has a few on the site but I don't remember seeing to many 4 stroke options.
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  9. bkoz

    bkoz test

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    Piston time. Ring end gap is in spec with the new rings. I buffed the cylinder with scotchbrite. I do not have a Nikasil specific hone brush on hand. The crosshatch is in great shape. You can still see the marks from the piston scuff but they are just staining at this point.

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    The Vertex piston uses a 3 piece oil ring vs 2 piece KTM.

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    This right here is made it all worth pulling the engine. The clearance to get the wrist pin retainer clip is very tight. And I don't have the fancy KTM tool. I put the head stud nuts on to prevent the cylinder from moving. I then flipped the engine on it's side. This made it SO much easier to install the clip. Well worth the extra 10 minutes it took to pull the engine.

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    Not a fan of the Vertex head gasket vs KTM.

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    But I am sure it will be fine. The head is back on. Next up are the cams etc once the cam chain arrives.
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  10. bkoz

    bkoz test

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    While waiting on the cam I started on cleaning of the air box and plastic replacement. I HATE KTM's rubric cube subframe/plastic assembly. Way over engineered and complicated. And heavy! Anyways, now that I have that off my chest...

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    My wife went out shopping for a couple hours. She should have known better.

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    Ready to Race

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  11. bkoz

    bkoz test

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    Swing arm service time. The bearings will be re-greased, duct tape for the swing arm guards replaced and chain adjusters never seized. I also had some filing and grinding at the chain guide area. To many rock hits.

    PXL_20210109_153959423.jpg

    I use this grease on all my suspension and head set bearings. It is absolutely tenacious and once in place is a bear to remove. It is awesome stuff but a little hard to find. Houghton Aquashield. Oilfield and marine suppliers carry it. The Houghton company supplies the offshore oil industry with product.

    PXL_20210102_192810451.jpg
    These are what the bearings look like after riding in a very wet year that included lots of studded tire snow riding (snow riding is hard on the bearings). Aquashield is great stuff.

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    My upper and lower shock bearings are starting to get some play. I am very happy they lasted 200hrs. On my previous KTM PDS bike the lower shock bearing needed replacing every 40hrs. But I have started packing the bearings with Aquashield to keep the water out. Inspecting these bearings is very important on the new PDS bikes. Lot of guys running into worn shock bodies.

    PXL_20210102_190850440.jpg

    More to come...
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  12. N8

    N8 Masked pumpkin rider Supporter

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    :photog
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  13. oldfuddy

    oldfuddy Long timer

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    Showed your dishwasher pic to my wife... she lead me out to my garage and pulled a pair of channel locks out of my tool box... she said, “Remember, I know where you sleep and where these are”.. “stay away from my dishwasher”.
  14. scotts630

    scotts630 n00b

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    Dishwashing pic... LMAO
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  15. bkoz

    bkoz test

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    My wife came home and asked if I had left to door open to the garage because "it smells like a dirt bike in here".
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  16. oldfuddy

    oldfuddy Long timer

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    Hilarious!
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  17. oldschoolsdime92

    oldschoolsdime92 Been here awhile

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    Better than smelling like strippers! LOL! Thanks for taking the time to post all the pics!
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  18. Retumbo7

    Retumbo7 Engineer

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    This is 60 hours. Slightly worse than 45 hours, which was slightly worse than 30 hours, etc etc.

    [​IMG]

    At what point should I crack the top end (even to just take a look)? I'm starting to doubt I'm going to make it to the 135hr recommended interval.

    Also I think I'm going to follow Bkoz recommendation and start doing my oil more often. I thought I was OK to go full 15hrs as I wasn't racing, but starting to get spooked. Will also be riding this one more now that I sold my 520.
    Mikemm likes this.
  19. N8

    N8 Masked pumpkin rider Supporter

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    I don't think that's due to your oil change intervals. I raced my 17 FE in Enduros and Hare Scrambles and I changed it every 3 races which was 10 hours on average. I used Rotella T and it came out looking like it went in. Nothing ever on the drain plug. I'd be investigating if I were you.
  20. bkoz

    bkoz test

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    I do not think that this has anything to do with the top end.

    If it was you would see other signs. Oil loss, blue smoke or someone complaining of smelling burnt oil while following you or even top end noise. A leakdown test is a must do if you truly believe the top end is on its way out.

    Do the particles on the end of the plug feel like sludge when you rub with your fingers?
    If so this is most likely very fine particles from your transmission gears and clutch. If so don't worry about it. I would reduce your oil drain intervals.
    Any large chunks of metal in the suction screen? A few small shiny flakes are normal.

    What kind of oil are you running? What kind of riding does the bike do? What kind of rider are you? This all factors into oil choice, oil type and change intervals.

    It wouldn't hurt to pop the valve cover off and take a peek at the cam lobes and finger followers to take your mind off things. Those two areas are very susceptible to oil issues. My guess is that they will look fine.