F800gs - Almost perfect except for poor suspension.

Discussion in 'Parallel Universe' started by mac444, Oct 22, 2008.

  1. Snowy

    Snowy Long timer

    Joined:
    Dec 2, 2008
    Oddometer:
    2,562
    I had leaky seals on my dirt bikes Showa forks a week ago. I used a 20 thou feeler and gently got it under the seal lip (after removing the scraper seal first) and as I worked it around I hosed into it with degreaser (hydrocarbon type in a spray can).

    A fair amount of crap came out, and it didn't leak at all on Saturday.
  2. TowPro

    TowPro Single Track Geezer

    Joined:
    Aug 21, 2009
    Oddometer:
    4,618
    Location:
    A mixed blessing
    I use bussiness card type stock for this (on my USD dirtbike forks). I fear the feeler gauge cutting the seal.
  3. LukasM

    LukasM Long timer

    Joined:
    Nov 15, 2006
    Oddometer:
    5,511
    Location:
    On a RTW ride - currently touring the U.S.
    I've tried business cards, film negatives, feeler gauges and pretty much everything else that has been recommended. Spend $25 and get this instead, much much nicer:

    [​IMG]
  4. ecce

    ecce Been here awhile

    Joined:
    May 20, 2009
    Oddometer:
    129
    Location:
    Stockholm, Sweden
    Given that the f800gs is a general pupose standard dual sport bike, not to be confused with ready to race dual sport bikes such as ktm 690 enduro, it does pretty much what it should and performes as can be expected.

    Most ppl would like if 8gs had more options in terms of settings for the suspension, of course.

    I have had such incredible amount of fun with this bike. It constantly surpises me in terms of what it is capable of and most of the time my own capacity as well as the tires are the limiting factor.

    It also makes me happy to see all the options available on the aftermarket to make it even better.

    When I have tried to dial in the correct sag for the bike I have never managed to get it right on the front so I decided to buy a litle bit stiffer springs from ohlins which cost me 120 euros and took an hour to install.

    I also think it is fun to watch all the stuff ppl put on the ready to race machines. I think we just have to accept the fact that most people who own a bike want to make it better if it is possible. Where better is subjective.

    And on a final note. I think the fact that BMW put on a 17" tire in the rear is a good indication of where they expect a majorty of the owners will be traveling. i.e onroad and not offroad.

    PS I think it is funny to note that a clutch lever from touratech is pratically the same cost as a set of new springs from öhlins. DS
  5. Snowy

    Snowy Long timer

    Joined:
    Dec 2, 2008
    Oddometer:
    2,562
    Been trying to find them in Oz, but the local bike shop staff look at me like I'm one of those crazy homeless people rambling and smelling of cheap wine and poo.

    Maybe I need a new deodorant?
  6. LukasM

    LukasM Long timer

    Joined:
    Nov 15, 2006
    Oddometer:
    5,511
    Location:
    On a RTW ride - currently touring the U.S.
    Ain't the modern world of mail order great? $4.60 shipping to OZ, which is a 1/4 of what the local bike shop will charge on top of normal retail...

    http://www.ebay.com/itm/RISK-RACING...08?pt=UK_Motorcycle_Parts&hash=item25708d7c90
  7. Snowy

    Snowy Long timer

    Joined:
    Dec 2, 2008
    Oddometer:
    2,562
    Thanks Lucas.

    I'll find one that isn't in the UK. I've had bad experiences with eBay purchases from the UK. There's a reason they populated half the world with convicts.
  8. mostro900

    mostro900 Adventurer

    Joined:
    May 30, 2008
    Oddometer:
    80
    Location:
    Sydney, Australia
    I'm pretty sure that those Seal Doctors were developed in Australia. Check www.ballads.cc to order. It's an Oz site.
  9. Snowy

    Snowy Long timer

    Joined:
    Dec 2, 2008
    Oddometer:
    2,562
    I knew I'd seen them somewhere here.

    Cheers. I'm amazed at how well the fork seals are sealing now. They haven't worked this well in a long while. I was going to just rip the forks out and drop them in for a rebuild...they're off my trail bike and they've done a very hard 20000kms of trail work. Now I think I'll change the oil and just keep going.
  10. The Griz

    The Griz Long timer Supporter

    Joined:
    Nov 26, 2008
    Oddometer:
    3,905
    Location:
    Earth
    Being a regular trail rider and enduro rider of a 2010 G450X, I can say with confidence that what you have been told regarding the 450X front end is not entirely true.... dependent upon which model year you speak of.

    There has been a lot of confusion about the front forks on the G450X. Let me clarify....

    BMW made the G450X for two model years: 2009 and 2010.

    If your informant was speaking of the 2009 model year G450X with black Marzocchi forks, they'd be pretty spot on. The 2009 Marzocchi front end was horrible on the G450X....for enduro/trail use that is. SUPER stiff. Like motocross stiff. Great if you wanted to take a double on a supercross track, but horrible for us enduro/trail riders. It's not that the 2009 Zokes weren't "up to the task", it's just that they were far too up to the task so to speak. Too stiff to be usable on anything but a motocross track. Stiff is good on the jumps, but not good for 70 miles over roots/rocks/chatter/stumps/logs/etc.

    However, if your informant was speaking of the 2010 model year G450X with the gold Marzocchi forks, they'd be dead wrong! I've ridden my 2010 on single track trail in the woods virtually every weekend for almost two seasons now (live in MN, yes we have seasons). I also rode a 76 mile enduro with it last Fall, and will be riding two more enduros with it this season. The suspension on the 2010 model year is superb. Super-plush. Soaks up the roots/rocks/chatter/stumps/logs/etc. like nobody's business. At a recent trail ride I swapped bikes with a friend who is a far better rider than me, races enduros and hare scrambles regularly. After riding my 2010 for a while his words were, "I haven't felt suspension that good since I rode *****'s bike.... and his suspension was custom built and cost $5,000".

    BMW completely changed the forks between the 2009 and the 2010. In short 09 bad 10 good.

    Another important point is that the suspension on the 2010 G450X is setup for a 165 lb rider for enduro use, and the G450X weighs 260 lbs. It would take quite a rebuild on the 2010 G450X Marzocchi fork to make it suitable for 400 lb bike with a 185 lb rider on it: complete revalve, respring, re-oil. Could be worth it for some though.

    Hope this helps. :D

    Some light reading as well:

    http://www.dirtrider.com/features/online-exclusives/141_1008_2010_bmw_g450x_first_test/
  11. Snowy

    Snowy Long timer

    Joined:
    Dec 2, 2008
    Oddometer:
    2,562
    Yeah, I had heard about the differences. But a front end swap to something as big as the F8 would require a full rebuild as a matter of course.

    I've done 4 front end swaps from motocross bikes to 650s, and in general I can buy the front end complete from the US for around $300. Add around $130 in postage to get them here, then add about $500 for rebuild, springs, revalve, seals, bushes, etc.

    I use the front wheel that goes with the forks for ease of compatibility. An aftermarket wheel with billet hubs, race rims, and heavy duty spokes is perfect. Upgrade to Motard brakes.

    I've been looking at the options for the F8, and nothing short of a $1500 budget sees it sorted in any way shape or form. I had decided to go with the Racetech cartridges, but cancelled as it would still be the F8 front end with all the limitations and just slightly better damping.



    But I do have en entire spare RMZ450 front end sprung with 0.55kg/mm.....coincidentally the same spring rate my F8 uses. It's too light on the F8 with crap damping from the standard forks. But with proper valving it'd be perfect for trail chop and rocks.

    Very problematic. But doable. I just have to build up the courage to completely gut the F8 and start from scratch.


    I emailed WhitePower about buying an entire front end new....and 5 CC'd emails and 3 months later I still haven't heard back from them. Obviously business is booming for them.
  12. Gangplank

    Gangplank Advenchaintourer

    Joined:
    Jul 20, 2003
    Oddometer:
    2,316
    Location:
    Las Vegas
    Sounds like you guys are doing it the hard way. I followed another inmate's idea an took the internals from an Aprilia RXV 450 and machined the fork bottom on the BMW F8GD to accept the bottom foot adjuster. A revalve by a local shop & I have a great handling F8. Cost less than $500 if I recall.
  13. Snowy

    Snowy Long timer

    Joined:
    Dec 2, 2008
    Oddometer:
    2,562
    I don't want to seem like a dick, but sometimes that just happens...so you'll have to forgive me.

    I'd rather start from scratch with something made to take the punishment.

    Something readily available. Over here the internals from an RXV are about as common as chicken egg sized diamonds. Generally they reside inside someones very rare RXV. People can get very touchy about you taking their bikes so you can chop them up for parts. People with rare bikes don't sell them much, and part them out even less, and when they do they want stupid dollars for the parts.

    I'm sure the RXV setup works well. I'd like to use something I can get parts for easily, and can find those parts at the local bike wreckers if I have to. They just didn't sell enough RXVs here for there to be any parts available. They were a limited run item. Great if you can find them in markets where they sold more volume.



    The general criticism I make of BMW here is that for the same price as their junkyard Marzzochis they could have fitted the bike with very nice Showas or something similar. Something that works, versus something that really doesn't. Something proven with readily available parts and mods already out there in the market.

    Yeah, some people are as happy as pigs in shit with their standard F800. More power to them.

    I'm not one of them.
  14. Snowy

    Snowy Long timer

    Joined:
    Dec 2, 2008
    Oddometer:
    2,562
    As it just so happens, as these things often do, by shear random coincidence the steering head bearings in the BMW are 52mm outside diameter.

    Almost every Suzuki dirt bike has a 52mm outside diameter bearing. The steering stems are also the same height, give or take a couple of mm.

    That just about seals the deal.
  15. Ducksbane

    Ducksbane Quaaack!!!

    Joined:
    Dec 27, 2007
    Oddometer:
    1,288
    Location:
    Northern NSW
    I am far from a riding God, but I have always been unhappy with the forks on the F800GS. I previously fitted progressive hyperpro springs (at the back as well) and speed bleeders, and it was much better, but I was still frustrated by the forks.

    Recently I just happened to have a spare pair of XChallenge fork cartridges, which are not very highly regarded, but certainly look a lot better than what comes on the 800. They just bolted straight in to the 800 with a spacer to reduce the travel to 245mm (15mm more than stock) and spacers for the springs to take up the extra travel and get the preload right. With 5 weight oil and a 80mm air gap as suggested by a suspension expert I am currently quite surprised by the results.

    I like to take my time getting used to big changes in bikes, but straight away I am a lot happier with the 800GS. On the road it doesn't dive nearly as much when braking and it now seems to absorb little ripples and bumps in the tar instead of bouncing off them.

    Off road it feels much more plush and I haven't bottomed them yet, which I am sure I would have before. It's just a much nicer bike now ... I'm really surprised what a difference this has made.

    If only BMW had specced this level of fork cartridge (still a lot cheaper than most bikes like Husqvarna 610's) I am sure a lot more people would have been happy with their standard suspension, and only those who really ride their 800's hard would have wanted to make a big change.

    Still a bit more acclimatisation and testing to do before I can be completely positive about this mod, but initially it's looking really promising. I really enjoyed my last ride on it.

    Typically the XChallenge is regarded as having poor fork cartridges as standard (impossible to revalve for example) and I agree compared to what is possible with higher spec cartridges, but they really are much nicer than the 800's (they have hydraulic bottoming circuits for example). If anyone wants to try this there must be a few XC cartridges and forks out there that have been replaced by better stuff. The secret is not to pay too much, and don't expect that the 800 will suddenly feel like you have spent thousands on it, it won't but it as far as I can tell it will feel a lot better.
  16. Gangplank

    Gangplank Advenchaintourer

    Joined:
    Jul 20, 2003
    Oddometer:
    2,316
    Location:
    Las Vegas
    No offense taken at all. But you do realize you can do the same internal swap with a set of Showa forks or any other fork that has roughly the same 45 or 46mm forks right? (outs are 45 so a 46 should fit).

    The only added complication is the fork caps. You're options there are to either a) machine the BMW fork caps to accept the rebound adjustment screw from the donor forks or b) machine the fork caps off the donor bike to fit into the BMW fork. Either way this will still be $hundreds less than a complete front end swap. There are probably thousands of good used shows forks around that could work. They don't even need to be in good condition. All you need are the internal parts. So even of the donor forks have leaky seals, are scratched or even bent they will prolly work. Usually it is the external tubes that bend. The internals are rarely bent and will just straighten out when removed.

    This is how road race bikes have been upgrading for years. If you want a better front rim then have one built. The rest if the BMW set up is perfectly fine.

    Oh and the same marzocchi fork used on the RXV is also used on husky's, gas had bikes, and some BMW models. It is a standard USD fork design. The ones on the BMW F8 are a cheap version. That's the problem. Marzocchi makes excellent forks on the upper end. BMW just didn't buy those. It bought the bottom barrel "pumping member" forks. And they are terrible on and off road stock.

    Either or any fork you choose for an internal swap will be better. Just needs to have enough travel. You can shorten the travel with an internal spacer. You can't make it longer though.
  17. Snowy

    Snowy Long timer

    Joined:
    Dec 2, 2008
    Oddometer:
    2,562
    Ducksbane:

    Yeah, your experience is pretty much what I'd have expected from the swap.

    I've found motoX forks work well in a swap onto a bigger bike because the valving in them works without modification. Most of the time the spring rate is comparable anyway to the bigger bikes stock spring rate. So off the bat you have a better set up without having to change anything. As you learn to ride it to it's potential you start tinkering with spring rates and valving.

    It's an evolving process. You make an improvement, learn how to utilise it, I'm talking in an off road environment, and them you make alterations and improvements along the way. Each time you figure out how to best use it.

    Gangplank:

    I measured up the internals from the Showa USD forks from the RMZs. The 06(single chamber) was too big and so was the 07 (dual chamber).

    I may have to strip my spare set and see what I can figure out. They just happen to have some minor external damage, chrome scratches from big rocks etc. I cleaned them up, had new seals and bushes fitted, but only kept them as "spares".
  18. Gangplank

    Gangplank Advenchaintourer

    Joined:
    Jul 20, 2003
    Oddometer:
    2,316
    Location:
    Las Vegas
    I believe the Xchakkenge got different forks for different years. Some are good others poor. I think the gold colored ones are the good ones. The black are said to be much worse. Not certain on that.,,
  19. Snowy

    Snowy Long timer

    Joined:
    Dec 2, 2008
    Oddometer:
    2,562
    I measure the BMW forks top plug as having a 49mm thread (48.72mm).

    The 07 Showa dual chamber has a 50mm thread (49.77mm).

    The 06 Showa single chamber has a 51mm thread (50.68mm).



    Just enough difference to give you the shits.

    Same pitch.

    So, if I set the Showa cartridge in the lathe and take 0.5mm off the thread by setting it all up to cut a screw thread it theoretically should fit.

    then I just have to machine out the axle clamps to fit the rebound valve.


    This had better be worth it. Still sounds easier to just swap the whole front end.
  20. Gangplank

    Gangplank Advenchaintourer

    Joined:
    Jul 20, 2003
    Oddometer:
    2,316
    Location:
    Las Vegas
    You can do it either way. The link in my signature has info on how I did it.

    Other than what you have listed you just need to make sure it has the right travel, if its longer you can make a spacer. My suspension guy made a spring spacer to reduce the travel. That plus the valving, oil over air & right spring preload.

    If you want to mess around with a stem, bearing & tripples, wheel & brakes be my guest. For me this was easier & cheaper by far.