F800GS - RXV Shiver'ed Fork Conversion

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

  1. Camel ADV

    Camel ADV Long timer

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    We are both on about the same time line. Fingers crossed it works as planned!
    #21
  2. Gangplank

    Gangplank Advenchaintourer

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    Yep. My bottom feet fit like a glove. I've got high hopes for the rest of the project. :D
    #22
  3. -W-

    -W- Flying Finn

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    :clap

    I have done now 10tkm with mine Shiver'ed forks without any problems - it works if done correctly.

    By the way check that if they remembered machine little chamfer/roundin inside the lower leg and to that part were the bigger machined hole turns to slightly smaller machined hole. That edge shouldn't be completely sharp or it will 'cut' slice from your base valve's O-ring seal (or damage it) when you push the valve to it's place - seal could start to leak later on.
    #23
  4. Gangplank

    Gangplank Advenchaintourer

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    Yep. Mine is baby's butt smooth.

    BTW - I was discussing with my revalve guy the 40mm spacer to get it back to stock. He was not sure what you meant about the oil hole needed in the spacer. He said he had not seen one done that way before. He is going to take them apart, take a look and give me a call.

    Do you happen to remember the overall length of the RXV forks vs. the stock forks?

    Also the travel is 230 for stock and 300 for the RXV Shivers correct?
    #24
  5. -W-

    -W- Flying Finn

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    There is a small hole (like 1mm diameter or so) drilled through the hollow rod (which has the rebound adjusting rod in it) just couple of cm up from the rebound valve. This hole will be covered with that 40mm spacer if you don't drill similar or bigger (like I did) hole to spacer. Probably the hole isn't necessarely needed, but I didn't want to take any chances because there is definitely some reason why original Shiver forks have this small hole (both, Factory and RXV, forks which I have taken to parts have this hole).

    Don't remember the overall lenght of the forks, but you can pretty easily measure that by your self. How ever it is quite impossible to use RXV forks as they are in F800GS since upper tubes are much lower in RXV forks - your bash plate would go 'trough the groung' at full compression..

    And what comes to stock travels you are correct.
    #25
  6. Gangplank

    Gangplank Advenchaintourer

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    Yep. Got it & thanks. I appreciate the info. I talked to him about the oil hole in the damper rod. he didn't seem to think a hole was needed. I'll let him figure that one out and will report back what he says.

    RE: length. I took the forks apart before I remembered to measure them. He will probably put them together and see the difference. I trust your 40mm measurement and gave it to him. Will report back on that one too.

    BTW - thanks for being the PIONEER on this one. Great and easy fix so far. :freaky
    #26
  7. Gangplank

    Gangplank Advenchaintourer

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    Got it all figured. From above I notice that the stock forks are 890mm. I'll see if someone can re-measure and confirm that for me.

    The other issue of the hole in the damper rod being covered by the spacer is going to be solved by the use of a topout spring instead of a solid spacer. My suspension guy thinks that the spring will work better and we will cut it to the right length (40mm give or take) to reduce the travel down to 230mm.
    #27
  8. -W-

    -W- Flying Finn

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    There is already that kind of topout spring inside of the dampening cardridges of RXV and other Shiver forks. So if you use second topout spring for reducing the travel that spring should be really stiff so that it won't anymore 'bend'.

    Normally all the travel reducements for enduro bike forks (when they use same forks for supermoto and iceracing) are done by using solid spacers - at least in this part of world;) What is good in solid spacer is that you can lock it to it's place with locknut and therefore it stays (no matter what) at the bottom of the damper rod. If you don't lock it (or you spring instead of it) it may move up and down during suspension travel and leave marks to damper rod and then the upper cardridge seal doesn't seal that well if there is marks/grooves at the rod surface.

    Again I'm not sure if this will hapen in reality or not, but I didn't wan't to take any changes what comes to reliability. After all it is an adventure bike (at least that is my goal with this bike;) and therefore reliability of every mod which I do for my bike has to be at top level. That is one of the reasons why I didn't want to go for gas pressurised gardridges like Bitubo etc..


    And I'm glad if I can help you guys with this mod since I have got so many good advices and inspirations from this site that I am only happy if I can 'pay some of that' back by sharing this fork mod.:clap
    #28
  9. blacktiger

    blacktiger Tigers R great.

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    Seems like an awful lot of time, money and work when all you really needed was different springs and oil viscosity.
    #29
  10. -W-

    -W- Flying Finn

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    Yeah, right...:*sip*
    #30
  11. Gangplank

    Gangplank Advenchaintourer

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    really? $400-$500 isn't much. A few hours work. To get a real cartrige fork set up correctly and adjustible compression & rebound. Seems inexpensive & easy to me.
    #31
  12. Gangplank

    Gangplank Advenchaintourer

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    Yes, he mentioned that mine did not have the top out spring after taking them apart. He ordred one and also two different solid spacers. He is doing the rest of the work and adjustments once those parts come in.

    He mentioned that often the springs are tapered so they will stay in place. Once the parts come in he is going to come up with the best soluion for these forks.

    I'm getting him the stock measurements today:
    stock length 890 mm from top cap to axle (on the bike, on side stand)
    stock fully extended - 913
    stock fully compressed - 683
    stock travel - 230 (913-683)
    #32
  13. -W-

    -W- Flying Finn

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    Okay, your Shivers are then a bit different than mine RXV and Factory ones.. And if you really didn't have that small spring inside of the damping cardridge (sounds a bit strange..), then it is absolutely best way of putting that spring there for off road use.

    Interesting to see little bit different solution than mine is! Nice work!:clap
    #33
  14. Gangplank

    Gangplank Advenchaintourer

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    Yes, he found it odd too that there was no top out spring. It could have been removed by previous owner when he installled the stiffer .5 springs. Also he mentioned that the RXV springs are 1/4" or 6mm longer than the stock springs. Not sure if he's planning to cut them down or adjust the preload spacer.

    He's considering best way to do it. I'll report back with a description. Not sure I'll be able to get pics. It is a private shop after all. :D
    #34
  15. -W-

    -W- Flying Finn

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    I wouldn't mind seeing some pictures "inside of private shop"...:evil :rofl

    He does the spring fitment by adjusting the spacers. And it really doesn't matter that if the springs you have are 6mm or 10mm or what ever longer / shorter since the original springs are also "wrong" lenght to this setup anyway (spring plate is in different height and you really don't want to put so much preload to stiffer springs as the standart spring are having).
    #35
  16. Bartron

    Bartron 'Tenacious B' the Bike Punisher

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    :amazon

    Welcome to the Parallel Twins section. Here the forks feature no rebound, no compression and no preload. Oh, and did I mention the lack of a cartridge which could be re-valved if it were present in the first place?
    #36
  17. Gangplank

    Gangplank Advenchaintourer

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    #37
  18. Gangplank

    Gangplank Advenchaintourer

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    I should get them back from the fork Dr. Today. Can't wait to get them on the bike & try them out!!
    #38
  19. Gangplank

    Gangplank Advenchaintourer

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    I got my forks back today.

    Ed McCoy set them up as follows:
    Overall length measures 35.75" = 908mm so guessing 913mm (same as stock)
    Travel 230mm
    40 mm spacer used to get them back to stock. Instead of a solid space he used a spring + a 10mm(+ or -) solid spacer to make it the right length.
    14mm of preload
    .50 spring which was a 1/4" longer than stock (compensated for via the preload spacer)
    10 wt oil
    100mm of air-oil space (100 mm from top)

    Set both adjusters at 12 clicks out from full hard
    Compression on bottom
    Rebound on top

    Put them on tonight. Took it for a little quick ride around the block. They felt pretty good. Definitely different and better. High speed compression is way better - No more jolts from square edge hits and it felt like less dive on braking.

    I'll report back with more info tomorrow after I rdie it a bit.
    #39
  20. -W-

    -W- Flying Finn

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    :clap

    We must then have a bit different kind of valving (and maybe ports at valves also) since I have harder springs than you are having, but my fork is revalved and tuned to be best at 5wt Motorex oils when riding pure off road.

    My tuner said that I could try a bit stiffer oils if I'll do more dirt/gravel road type of riding or prefer a bit more damping and therefore I have now 6.25wt Motorex oils in those (because I just did 9tkm long summer trip with lots of good roads also). For winter I will go 5wt or even lighter oils (=temperatures below -0c).

    That 6.25wt blend of Motorex seems to have quite close same viscosity than original Marzocchi 7.5wt oil and much stiffer doesn't work that well with these forks according to him. But different brand oils have hugely different kind of viscosities and therefore some 7.5wt and some 10wt could have same viscosity in real life:

    http://www.pvdwiki.com/images/a/a7/PVD-ISO-Viscosity-Data.gif

    Just to remind when playing with different oil viscosities and brands..
    #40