F800GS "Drop-In" Fork Replacement?

Discussion in 'Parallel Universe' started by PenultimateMan, Oct 5, 2012.

  1. machinebuilder

    machinebuilder Long timer

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    could you reduce the picture size?
  2. PatrickM

    PatrickM Been here awhile

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    PC - "Ctrl -" to reduce size, Mac, "Command -", two keys simultaneously.
  3. biodieselandon

    biodieselandon Been here awhile

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    I talked to the guy at the Ohlins booth at the Seattle Motorcycle Show and he said they are already developing a cartridge kit for the 2013 F800GS and it should be out soon. He also said it is going to be a lot cheaper than the kits in the past. :clap
  4. Angryrican

    Angryrican know nothing all

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    I just installed a set of Xchallenge cartridges with Ohlins .55 springs and 7.5 weight oil at the Ohlins recommended 60mm air gap.

    I'm not sure how the Xchallenge gets 40mm more travel since the springs are the same part # as the F800GS and the cartridge bodies are actually 5mm longer then the F800's. the only thing I can think of is the 100lb weight difference and the preload spacer are what shorten the F800's travel. The fork legs extend within a few millimeters of where they did before install and of course the springs need to break in and settle so it should be the same.
    I won't be able to ride it today since we are getting 30-40 mph wind gusts but the initial few rides around the block seemed promising and nose dive under braking is now limited and smooth versus the previous quick and jerky:clap

    I spent $300~ on this mod, $100 for the cartridges used, $140 for the springs and $40~ for oil and new bottom screw washers and now I have adjustable compression and rebound damping:norton
  5. itsatdm

    itsatdm Long timer

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    Ducksbane has the same mod and appears happy with the result. He is running Hyperpro springs. Am I correct that these are a straight bolt in? If so I assume 1 leg is for compression and the other rebound?
  6. Angryrican

    Angryrican know nothing all

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    Yes, it is a direct swap. The left leg is compression and the right is rebound. This was not much harder then doing a fork service, 1.5 to 2 hrs tops!
  7. Casejeep

    Casejeep Been here awhile

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    Where were you able to get the used forks from? Any modification on the ABS or brakes?
  8. Angryrican

    Angryrican know nothing all

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    here in the flea market, there was a guy selling two sets a few months back. You are just swapping cartridges and top cap so nothing else changes.
  9. Sohere

    Sohere Adventurer

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    So these X Challenge cartridges are only compatible with those of a 2013 F800GS?
  10. Angryrican

    Angryrican know nothing all

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    They fit the 2012 and earlier bikes with the 45mm Marzocchi fork legs
  11. Angryrican

    Angryrican know nothing all

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    So after measuring and looking at the different parts between the XChallenge this is what I found and concluded;

    -The upper fork tubes are 40mm shorter on the Xchallenge allowing the extra 40mm of travel
    -springs are the same part # between both bikes
    -only the F800Gs has the preload spacer(most likely making up for the extra weight)
    -as said before this is plug n' play for the F800gs and requires zero modification to fit

    My first ride on pavement with a short but rocky 5 mile trail have proved promising so far, bike feels very planted on road and offroad it has become point and shoot vs. react and hold on for full stock(this is in conjunction with the Wilber's rear shock)
  12. Snowy

    Snowy Long timer

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    So what's the total travel?

    I can't remember what the advertised travel of the F800 was standard, but I do remember using the cable tie measuring process and establishing that the advertised travel was a bit more generous than actual. Especially so after the Ohlins 0.55 springs went in.

    having 300mm of travel now is magic. With proper damping it works so much better across all trail types.

    I had the Showa forks rebuilt for my 650, with fast hard trail work as a reference. Plenty of air time was factored in. This has translated very well to the slightly heavier 800. Even with lighter spring rates than the Ohlins springs I had, the Showas work so much better that there really is no comparison.

    I thought about the Xchallenge forks, but after talking to a guy that races one I was put off the idea. He reckoned I was better off looking at a complete swap. I'm glad I did now. There were some slight engineering glitches, but nothing insurmountable.
  13. Angryrican

    Angryrican know nothing all

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    I've been using the amount of measurable lower tube or the distance between the bottom of the upper fork tube and the bottom crown of the inner tube/slider, with the bike on the center stand I get 252mm, with it on the side stand 208mm, with me on it(using a zip tie ) 187mm~ , stock travel is advertised at 230, usually you get about 20mm~ before it really bottoms out so the 252 is spot on. After taking the bike for a few hours ride it is within a few millimeters of pre conversion measurements. The 187mm distance is within the recommend 25% sag.
    The one thing I noticed today is how smooth and stable the bike feels on the highway and how much easier it is to ride over 70 mph. I have a slightly worn TKC80 with about 4500 miles on it and it felt really smooth for the first time.
  14. Snowy

    Snowy Long timer

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    Yeah, we've talked about the wobbles in the front end before, and ITSATDM came to the same conclusion as me, or I came to the same as him, whatever....that dropping the front in the triples about 20mm seemed to fix the front end shake.

    The Showas have made it a bit taller in the front. I thought that this would translate to a very shaky head wobble. Quite the contrary. I looked at the amount of offset in the axle clamps on the Showas compared to the standard forks and there wasn't any great difference.

    It seems to me, that at the standard ride height, you are right in the zone where instability occurs. Raise it, it gets better. Lower it, it gets better.

    With the taller front, and the taller rear, I can only just get the rear tyre off the ground on the center stand on concrete. On dirt, the tyre is still in contact. I have the triples lowered on the Showas about 20mm. If I raise the front to full height I can't get the rear wheel off the ground. But it rides really nice on gravel set up like that.

    I might just lengthen the center stand.


    I got a bit carried away on Sunday and launched the bike off a cattle grid with wifey on the back. covered a good 20 paces off the ground and landed perfectly. Just the hint of a ding as the bashplate kissed the gravel. Wifey was floating with her feet off the pegs and her bum hovering above the seat and her nails dug firmly into my kidneys. She was pissed off and elated at the same time.

    For me, that is really the ultimate test. 2 up, punch some air, land like it should solo.

    It only took about $4500 to get there. Factored onto the cost of the bike, and all the other accessories, I still have change from a new KTM990. So glad I didn't go down that road now. I'd be looking at spending money all over again.
  15. Angryrican

    Angryrican know nothing all

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    I haven't put it thru it's paces yet but I think I got what I wanted which was some tuning ability, much better ride quality and rid of the squat and nose dive under braking(I use it to commute in New York City traffic a few times a week). If I don't find it up to speed long term at least it's a stop plug until the new Ohlins cartridges become available
  16. Snowy

    Snowy Long timer

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    The ability to adjust, and having some form of decent rebound and compression damping completely transforms the F800.

    This is why I get so frustrated that BMW wont fix it.

    It's such a versatile bike when done properly.

    What are they afraid of?
  17. Angryrican

    Angryrican know nothing all

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    I'm not sure how much the mod I did would have added to the cost of the bike but I can't imagine it being much and I'm aware that the spring upgrade adds to it but the adjustment alone would really help this bike.
  18. wipe-out

    wipe-out Been here awhile

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    i checked back with öhlins and they told me the kit unfortunately won't be available before april due to some complications.
  19. petzi-baer

    petzi-baer Been here awhile

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    I know it isn't quite April yet, but was there an update?

    Thanks

    Petzi-baer
  20. NCD

    NCD Dirty Hairy

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    I checked a little bit ago, it was still delayed. Meh.