F800GS - RXV Shiver'ed Fork Conversion

Discussion in 'Parallel Universe' started by Gangplank, Jul 25, 2010.

  1. epicxcrider

    epicxcrider Been here awhile

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    Sweet, those guys had fallen off my radar but I think I'll be calling them for.a quote today :)

    Thanks!
  2. epicxcrider

    epicxcrider Been here awhile

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    Called these guys yesterday, now just waiting to hear if they want to take on the job or not. Either way I'll be doing the machining...
  3. Gangplank

    Gangplank Advenchaintourer

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    The spacer my fork guru used was a spring. Small 40mm as a top out sping. I think it just sits on the rod and when it maxes out it is there.

    Running Maxima 10 wt. Run whatever you like but always use the same oil each change or when changing weights use same brand. Why.... b/c fork oil is not very consistent and one companies 5 wt may be another companies 10wt or 15 wt.

    The Aprilia springs come in two different stiffnesses. Check AF1's website and they will show them for sale as regular and stiffer or somethng like that. Mine came with the stiffer springs. I'm guessing there must be a marking on them to tell which is which so maybe email AF1 or call them and ask. They are pretty helpful dudes.

    My seals were good. You have to be careful when taking them apart. Since you have 4 seals between the two sets of forks my guess is you should have two good ones.
  4. epicxcrider

    epicxcrider Been here awhile

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    Thanks!! Don't know if I'll get to it today but hopefully this week ill have an update. Things got crazy and I couldn't pull it apart yesterday. Just ordered some 10 wt oil.
  5. PenultimateMan

    PenultimateMan Lost Boy

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    Has anyone else done this conversion aside from -W-, Gangplank, and EpicX? Does anyone know if EpicXRider is even still alive?! Will we find the answers to these questions and more in next week's exciting episode? I choose to think that the reason he hasn't updated the post is that the conversion was so successful he's scarcely been off of his bike all summer.:clap

    The time approaches for me to finally drop coin on my own F8, and though I'm certain about the purchase, the more I read about the horrendous brake dive (to say nothing of the off-road issues) perpetrated by the front suspension, the more I'm convinced this is a practical necessity for any real riding in the places I want to go.
  6. Ilipo

    Ilipo n00b

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    With a good guidance from -W-

    As also written somewhere earlier, the trick is to get the fork tuned by some suspension guru... Mine is still not done and I must keep the compression dampening all the way open. Otherwise the fork is too stiff/slow (atleast for me)

    -Ilipo
  7. PenultimateMan

    PenultimateMan Lost Boy

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    Do you mind me asking how much it ended up costing in total? AltRider's got a kit on his website for Öhlins cartridge inserts for something like $1800, but his description of the adjustability is vague, and that price seems WAY higher than what the total cost of this job should be.
  8. epicxcrider

    epicxcrider Been here awhile

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    Haha I'm still alive. I didn't have time to do the conversion before my trip and I spent the past three weeks riding it from California to Maine :)

    Conclusion: the fork needs to be upgraded and that's my new priority but I gotta write a trip report first :)

    Also my advice to anyone is put a few thousand miles on it so you know exactly what you want to change.
  9. Ilipo

    Ilipo n00b

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    It think the total cost was apprx. 600€ as I did not have to pay for the machining... I assume it's going to cost me another 150€ to get the fork fine tuned...

    The majority of the cost comes from the donor fork... So you might want to spend some time to find a good (and cheap) fork. Mine came from BMW G450X which requires bit more work than Aprilia RXV fork. In principle all the details can be found from the earlier posts.

    -Ilipo
  10. Gangplank

    Gangplank Advenchaintourer

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    Mine work great.

    If I recall correctly
    Forks were $150
    Shipping $25
    Machining $125
    Fork Tuning and revalve $200? (I did this on a trade with the guy)

    So that is about $500.

    It really is not as hard as it sounds. If you can find the RXV forks and find a machine shop to do the work the rest is a good suspension guy.
  11. Ducksbane

    Ducksbane Quaaack!!!

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    I did do my forks using my left over XChallenge cartridges. They have a spacer to reduce travel to about 245mm. There is no machining, you just change the cartriges. :clap

    Very impressed as cost was minimal as I had the cartridges already. I think the XC internals suit the 800GS better than the XChallenge ... great improvement on and offroad. Used my left over Hyperpro springs with a spacer for the extra travel. This is the only fault I notice ... forks top out at full extension a little bit, so I might try different spacers one day.
  12. PenultimateMan

    PenultimateMan Lost Boy

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    So if you just took the cartridges, I would imagine that the forks aren't adjustable. That hasn't been a problem for you, I take it?
  13. Ducksbane

    Ducksbane Quaaack!!!

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    The XChallenge cartridges are adjustable .... sort of ! :D

    In typical BMW style the XC has cheaper more compromised fork internals compared to "proper" Shiver internals. That being said, they aren't as cheap and crappy as the F800GS bits. They have proper compresssion damping adjustment on one fork and a more limited rebound adjustment on the other. Both adjustments are on top of the fork like the rebound adjustments on "real" shiver forks. Therefore you don't have to machine the fork bottoms for the compression adjusters and they literally are a drop in mod. The best part about them compared to the original 800 cartridges is that they appear to have hydraulic bottoming circuits so that I no longer have that terrible crashing, clunky bottoming happening.

    It would have been very cheap and easy for BMW to have used cartridges like the XC (and HP2) ones in the F800GS. Some people would have found that they weren't good enough, but most people would have been happy, and they would have had some adjustment to play with.

    YMMV as they say, but I'm pretty happy with the 800's suspension now. The rear (with Hyperpro progressive spring) is now the weak link, but I'm not sure I could really justify big, expensive changes at the moment, it all seeems to work pretty well. THe suspension people who did the work for me have a rebuild with modification for the rear shock, so maybe I'll go that way later.
  14. Gangplank

    Gangplank Advenchaintourer

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    Mine are the RXV so they are adjustable, but still once dialed in I rarely touch the adjusters.
  15. Gangplank

    Gangplank Advenchaintourer

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    Nice one ducksbane. Sounds like a good fix
  16. BDevilGS

    BDevilGS n00b

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    Hi.Can I use the fork internals from Husqvarna TC 570?Thanks,Bernard.
  17. Gangplank

    Gangplank Advenchaintourer

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    According to this site: http://www.esuperbike.com/new_vehicle_detail.asp?veh=2497&Manufacturer=40

    The 2001 used the 45mm Marzocchi inverted hydraulic fork with adjustable compression and rebound damping, 12.6 in travel.

    Looking earlier in this thread:
    From what I can find online http://slorider.com/Aprilia/manuals/Specifications.pdf the travel of the RXV Marzzocchi Shiver forks I used was 298.5 mm (11.75 in).

    The stock BMW's are 230mm or 9 inches. I gave this info to the guy who revalved my forks and he was able to make a spacer to shorten them to the stock length and travel.

    I believe it was a 40mm spacer spring + a 10mm solid spacer (~2"). So the 11.75 was reduced to close to stock.



    So to answer your question, yes you should be able to do it by using a spacer to shorten the travel from BIG TIME offroad travel to dualsport range of the BMW.
  18. BDevilGS

    BDevilGS n00b

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    Many thanks.This is what I needed.:clap
  19. bikecat

    bikecat Long timer

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    Dear Gents,

    I have been following these threads as I am keen to also improve the handling of my MM. Yes, not quire parallel universe but we share the same forks. :)

    The MM is a tall bike and I cannot say that I am tall, so the Wilburs lowering fork springs are attractive. They also do 2 for the F800GS as well - (part number: 600-0325-08 and 600-0326-04). I bought the ones for the MM and amazingly these springs are longer than the stock ones (left one is stock):

    [​IMG]

    What is interesting is that while the BMW manual prescribe an air gap of 80mm, the Wilburs prescribed one of 175mm, more than double. The mechanic who installed the Wilburs mistakenly used 80mm and now the bike is higher than stock, and the front seems harsh. I will install the recommended gap of 175mm, and keep you posted on the outcome.

    Sorry if I had hijacked the thread, but I thought you guys might be interested in this.

    Cheers
  20. BDevilGS

    BDevilGS n00b

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