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F800GS - RXV Shiver'ed Fork Conversion

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

  1. Reaver

    Reaver How Did I Get Here?

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    I guess it gets all confusing with the lowering this and raising that.

    See in my pic that the upper fork tubes (beside the handlebar risers) are raised in the clamps? By doing this it lowers the front end.
  2. Anti

    Anti Νέος

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    You mean the upper "steering" plate?

    My problem/concern is not how rised is the handle bar (I don't have any issue on that) but how these higher 2cm may affect the bike's "behavior".....
  3. Reaver

    Reaver How Did I Get Here?

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    OK, let me try again.

    Not your handle bars or the steering plate as you call it.

    Each fork is bolted into the top and bottom triple clamps. You remove them by loosening the bolts on the triple clamps or steering plates as you call them. Their position is set, then you tighten the bolts to secure. Well if you loosen the bolts you can slide them further upwards 25mm before you tighten the bolts. Make both sides the same. That will lower the front of your bike.

    I need to make a picture but not now.

    Yes?
  4. Anti

    Anti Νέος

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    I see, I ment the same thing but I described it differently (sorry for my English.....)!

    To tell you the truth, I do not really mind how rised is the front (from driving perspective-> how comfortable is....) my concern is only if this rise will affect the bikes behavior on the road at high speed, over e.g. 140!
  5. Anti

    Anti Νέος

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    After some km.... the bike's behavior is by far improved, and the braking too! I've also rode it at some high speeds (140+) and it was really stable, nothing to worry about.... by the end of the month I will also try it on a 1700+ km off road trip (but I can imagine how it will be :-D)

    By far...... a value for money improvement!!!!!!!!

    Thank you guys!!!!! As I learn about all this "change" here.... and went for it!!!!!
  6. lancer66

    lancer66 n00b

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    Would you consider selling the fork upper tube if you still have them
    thanks
    Lance
  7. bondyzf

    bondyzf Adventurer

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    have any of you guys ridden with the stock set up in the conversion ?

    how was it ?

    I have a set of gas gas forks ready to do the conversion and was just wondering what it was like without revalving
  8. Bayner

    Bayner Long timer

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    I tried it for a while in stock form, mine were from an Aprillia dirt bike I believe. It was better than stock, in that it wouldn't deliver those hard hits at high shaft speeds. Try it and see. It's not too much work to pull apart and revalve if you don't like it. Should shorten the stroke too, unless you're using the stock spring.
  9. Mconnell

    Mconnell Adventurer

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    I used gas gas forks in my conversion. I think you will find the stock valving way too soft. I revalved them myself. The shim stack is substantially stiffer than stock now, and is still plush without wallowing.
  10. Nick V

    Nick V Who dares, wins.

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    Hi all!

    I've just bought a front-end accident-damaged '13 F800GS that I plan to modify heavily.

    This thing's going to be my 'All-singing, all-dancing' bike. For my requirements to be better understood, here's a little background on what it will actually be doing:

    • Long-distance commuting (I ride 172 Km every day).
    • Iron Butt runs.
    • Sunday morning breakfast runs (solo and two-up) at very high speeds.
    It will not be used off-road - this bike will be kept strictly on tarmac. To that end, I'm converting to a 17" front wheel.


    I know that this thread talks exclusively of the Marzocchi Shiver-type forks fitted to '08-'12 GSs. What I need to know is, how much of the info is relevant to the White Power forks fitted to the later bikes? I owned an '08 F800GS with unmodified suspension back in 2012, but have never ridden one of the newer F800GSs. At any rate, I doubt I'd remember enough of my old bike to compare it with the new.


    So...

    • Would this conversion be relevant to my needs?
    • I need an additional 2" in static fork length to compensate for the different front wheel. What are my options, besides having the standard fork stanchions extended?
    • Can anyone recommend a suitable pair of forks I can pick up from a breaker's yard, or from any particular standard bike?
    Advice and counsel greatly appreciated! :clap Thanks, ladies and gents.


    Nick
  11. bondyzf

    bondyzf Adventurer

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    cheers for the info guys

    the donor forks I have are from a 2003 gas gas 450fse and have the ti nitrate stanchions,does anyone know if the stanchion length is the same ?

    I was thinking of swapping the stanchions over
  12. sarathmenon

    sarathmenon Armchair Adventurer

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    I have a spare 17" front wheel that I occasionally use, if this is going to be your permanent setup, I'd suggest investing in a steering damper. The shortened rake and trail make the bike slightly twitchy at 80+ and in fast corners. It's mostly stable, but I'll probably add one just for a peace of mind.

    Not much. The WPs use a different triple tree, according to the parts fiche. If you want to go the shiver route, you'll need to get a pre-2013 upper and lower triple tree as well. You can see the cost climbing up, it's probably not worth doing.

    Most of this depends on how much of the front end is intact. If you are doing major shopping, you might as well look for a triple tree + forks + front wheel used on ebay from any modern donor bike. Any long travel KTM should fit the bill. Also, if this is going to be your permanent setup, add the shorter F800GS shock, and shorter side stand to that list as well to balance the geometry. I get by with the preload cranked down on the standard shock when using the 17" wheels, but the lowered shock is probably a better fit if you don't plan to change it.

    In general, you should be able to shorten the travel of the standard issue forks with a topout spacer. Just about any fork out there is going to be an upgrade over the stock forks :D Oh, and look here for how an inmate did this right.

    One more thing - it's a lovely setup. The bike handles just about perfect with street wheels.
  13. Nick V

    Nick V Who dares, wins.

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    Hi Sarathmenon! :D

    A very detailed reply, for which I thank you!
    My last post was rushed - I should have given a lot more more detail than I did. I do most of my posting on UKGSer and the full story can be found at http://www.ukgser.com/forums/showthread.php/383846-Converting-an-F800GS-to-belt-drive, but in a nutshell, what I'm doing is converting a 2013 F800GS into a sort of Hypermoto thing by:

    • Replacing the standard engine/gearbox with one from an F800S, ST or GT. This will give the bike belt drive, single-sided swingarm and 5.5x17" rear wheel, all in one go.
    • The above rear will be complemented by the front 17" wheel, 320mm discs and 4-piston brake calipers from the same donor bike. (The increased braking power will be one of several reasons why I want high-quality USD forks).
    • Whichever forks I eventually choose will be modfied to the following length: (standard GS forks + 2" extra stanchion length). Trail will be reduced in any case by reducing the front wheel diameter - but I can at least keep the rake more-or-less the same.
    As you'll see if you look at my thread, the conversion is already pretty far advanced.I've hit no serious snags so far, and am currently eliminating spacing conflicts from the area around the swingarm pivots, and engineering new load-distributing rear engine mountings that will enable the GS frame to take advantage of the S/ST/GT engine as a fully-stressed member. :clap


    I have a vague idea that I'm debating putting on my list of 'things to do' - taking the standard S/ST/GT steering damper and moving it to the area around the top triple clamp (in the same fashion as the old Ducati 916).
    If I do, I'll design in a variable-leverage linkage so that damping can be increased or reduced without having to change the damper valving.

    Amen.
    What I'd really like to do in order to avoid having to transplant vital fork internals from one bike to another is mildly modify and slot in a complete, intact set of forks from another bikes.
    So far, on possibility I've heard of are WP 4860s. I'll be looking at other alternatives this week, and suggestions are always welcome!

    My circumstances are obviously slightly different - again, I should have mentioned it earlier.
    The S/ST/GT swingarm uses a different shock mounting, so I may have to either use a modified S/ST/GT shock or modify the GS lower shock mount.

    You shouldn't have shown me that... I am now officially 40 shades of green. :cry
    I would give an arm to have learnt 3D modelling at an earlier age, and to have that machine shop setup.

    I've built three 'Supermoto' conversions from Hexhead (OHV) and Camhead (DOHC) R1200GSs and GS Adventures.
    One used the 5.5x17 rear and 3.5x17 front from an R1200RT, one used a 6x17 rear from a K1200S and 3.5x17 front from an R1200S. The third one used a standard 6x17 rear from a K1200S and a modified 3.5x17 front, also from a K1200S. All used the standard R1200GS brakes and suspension.
    Fond memories of all. :D
  14. sarathmenon

    sarathmenon Armchair Adventurer

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    First thing - we demand pictures, and a detailed build thread. We have high standards, and won't accept anything less in these parts :D
    I am an expert in messing with people, so let me put another option. The F800R is chain driven, and shares a lot on the tail end with the F800GS. It's ridiculously silly to use the F800R rear wheel on the GS. You need minimal machining - a new LHS spacer and a rotor spacer. This lets you keep the GS' rear swingarm, rear shock, chains, counter sprocket, sprocket carrier etc... And in your applicaiton, you also get to keep the stock engine, rear sub frame, shock and what not. In my hot swap requirement, I use the same counter sprocket on both wheel sets and don't even have to dick around with the chain adjusters.

    Now, if you hate chains and their maintenance, I can understand. But at the same time, if tubeless super sport size rims are your goal, your wallet will be much heavier if you go this route. if you need more information, I can start a thread about it.
    The GS' stock brakes aren't bad, as long as you don't compare to the sport bike mono-block units. Most people here complain about the fork dive, but rarely over the stopping distance with the 300mm discs. Upgrading to wave rotors also help. All things remaining the same, the 320mm rotors should be an upgrade, but it won't be as dramatic as you think.
    Without knowing the final shock travel you will end up with, it's hard to speculate, but you are on the right track.
    Both variants if I recall correctly are stressed members, but the GS cylinders have a forward slant when compared to the upright placement on the roadsters. I haven't looked it up, but the trellis frame on the S vs the GS are probably different. I can imagine that the game of mix-a-lot will be tricky. You probably are on the right track in trying to bolt on the crankcase from the S to the GS. Sounds like a lot of work, but you already know that :D
    Hmm, adjustable fork mount Ohlins damper time? Probably cheaper too when you factor the machining/engineering time and effort for your approach.
    What's your plan around the front ABS sensor ring? The F800 roadsters use the 60 teeth (or something like that) R1200GS ABS ring. The GS uses the smaller 48 tooth ring, and there is a wunderlich 40-teeth adapter available for 17" front wheels. I don't know what it takes to flash the GS' ECU to have it accept the other ring. Hexcode is in your neck of the woods, you should give them a call before you start piecing this puzzle together.

    My suggestion would be to first sort that out. If you end up having to use the lower forks from either of your donor bikes, that leaves a small subset of matching forks and internals when you go shopping.
    Don't have anything to offer, but it is hard work to piece everything together.
    Sure, welcome to the Finn fan club. Our numbers are growing at a fairly rapid rate :D
    I am looking at what it takes to mount a F800R front wheel to the GS, so I did some background research into it - the R1200GS has the same rotor bolt diameter, botl pattern, and ABS ring as the road going boxers - those conversions should have been relatively straightforward because those models share a lot internals. Don't get me wrong, you probably put in countless hours in the boxer conversions, but your current project is going to be at least an order of magnitude harder, and will involve some serious machining. Good luck!
  15. Nick V

    Nick V Who dares, wins.

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    Hi again! :)

    It's a good, simple alternative, but not practical for my purposes. I desperately wanted the belt... I hate chains on principle.
    Like a fear of flying or touching wood to obviate bad luck, very little of it has to do with sheer logic. ;)

    The other thing is that BMW never released the F800R in SA. It's never been sold here - I've never even seen one as a grey or special import!

    Not really. ;) I've built up a string of contacts that goes all over the country, and BMWs are popular enough here that there is rarely a shortage of whatever parts I need.
    The GS was bought at auction as a written-off wreck (front-end damage). As a donor bike for parts, an F800GT from the same source would be first prize, but I also have my eye on a stolen/recovered F800ST which I expect I can pick up for less than half of 'normal' retail price.
    All unused parts can be re-sold to generate funds - especially stuff like the original GS wheels.
    I had also been rolling this idea around in my head for ages, until finally I couldn't leave it alone. And as corny as it might sound, I wanted to work on something challenging.
    I got that...! :lol3

    It's OK, I'm not aiming to build an HP4-beater. ;)
    The math behind it adds up to a combination of several advantages - mainly the effect of a larger-diameter disc on a smaller-diameter wheel (both of which allow the (more powerful) calipers to gain more mechanical advantage).

    That's right. The GS engine is less stressed, because the swingarm spindle locating channel at the back of the engine does not clamp the spindle. So most of the stresses generated by the swingarm are carried by the rear of the frame.

    A Devil's alternative. Our exchange rate sucks a fat one.

    If I have a complete donor bike to play with, both its ABS sensor rings will be used in conjunction with it's engine ECU and ZFE-high. No worries.:thumb
    The rear speed sensor and sensor ring on the belt-drive swingarm will remain untouched. If I have to, I'll fabricate a bracket to hold the front speed sensor in the right place.

    Again, at the risk of sounding perverse, that's one of the reasons I did it. :D
  16. sarathmenon

    sarathmenon Armchair Adventurer

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    You don't need the entire bike to be imported. All you need is a used rear wheel, and there are plenty on ebay. It's probably going to ring you 500 USD with shipping, if you work with the seller, and it is far cheaper than getting a trashed S/GT/ST used. The front wheel on the R is a different part # from the belt driven cousins, but you could easily powder coat a locally available wheel - I am almost sure that the differences are only in the color.

    On the other hand, I can understand if you are motivated to get a belt driven GS. An itch needs to be scratched, and there is the fun of dealing with a good challenge.

    Yup, taking the donor bike's ECU should allow you to use the donor's ABS rings. However, you are also commited to several other things - you have to use the donor's dashboard, maybe the donor's keys. Another thing to note is that the roadsters have a different timing and valve overlap (don't recall the values offhand). Some people have said it's possible to reflash the engine map, but I haven't heard any clear confirmation of the fact. If you were thinking about using the GS' cylinders, that also would be something you need to sort out.

    Hey Reaver, did I cover everything?
  17. Nick V

    Nick V Who dares, wins.

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    Yup, that's basically the approach I'm taking. Which is why I'm after a complete donor. Buying everything 'piecemeal' simply works out too expensive.

    This is going to be a straight transplant - S/ST/GT engine and all peripheral components (with the possible exception of the wiring harness), straight into the GS frame. So I don't anticipate any power-delivery issues.
    There's an outfit in the UK called Hilltop Motorcycles that specialize in ECU re-flashing. UKGSer is full of peeps who sing their praises, but I haven't had the opportunity to deal with them - yet. Apparently, there re a handful of people in SA who do it as well - I have yet to track one down.

    As a side note, I was sceptical of the theory that instrument clusters are matched to specific ECUs and won't work on the non-original. About six months ago, I had access to the instruments from a crashed '07 K1200S. I plugged them straight into my '05 K1200S and took the bike for a ride. Everything worked perfectly. The only snag was that the 'new' cluster retained the mileage readout of the bike it came from.
    Just to be sure, I swapped the '07's engine ECU into my '05, hooked up the '07's transponder-key antenna to the wiring harness and taped the '07's ignition key to it as I turned on the '05's ignition.
    Same story. It fired straight up and all instrument functions worked fine.
  18. sarathmenon

    sarathmenon Armchair Adventurer

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    In your case, your transplant was from the same model - the differences in spec might have been the same. Based on what Reaver went through while trying to fit an F800GS instrument cluster onto a F650GS, the ECU doesn't like it when you swap between model variants. You'll be able to confirm first hand when you get your hands on the ST :D
  19. Nick V

    Nick V Who dares, wins.

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    I haven't read the thread, but differences in ZFE-high spec could also have had something to do with instrument clusters throwing tantrums...
  20. Reaver

    Reaver How Did I Get Here?

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    Two cents, or Rands or whatever.....

    The Ring Antenna is just an antenna. It cares not what bike it's installed on and is no way programmed to the bike. I've changed dozens.

    For proper ABS function, the instruments must match the bike model. An S panel will work just fine on a GS but NO ABS. Your experiment between K bikes didn't flag that because they had the same ABS unit. You'll have to match up all the computers if possible for 100% operation assuming the wiring will work. The ZFE may or may not care but probably.

    There's a lot we don't know about the interbreeding so you may get a ........(Un-PC R word). :eek1