An 800's Rebirth/The build of MechanicO

Discussion in 'Parallel Universe' started by FinTec, Dec 12, 2014.

  1. FinTec

    FinTec Been here awhile

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    No we need to just mount the Scott bracket onto the ignition post and we are good to go! Wrong :huh Like a lot of things, this was supposed to be easy and it was not. I had changed all the geometry from the way the stock bracket interfaces with the damper so the stock one just did not line up.

    Let me take a second to state this: Scott was amazing for support. They actually sent me a few of the "arms" in different configurations to see if to could get one to fit. And then I just sent back the ones I did not need/use. They we very supportive with all my questions and requests. :smile6

    So after getting options from Scott, staring at it for WAY too long I came up with this: I would take the stock bracket, weld to it, and then re-machine it to fit my application. I would be using the "flat" version of the Scott arm (seen a few pics down) as well. So in reality, I just needed to move the hole for the post back about 1cm. So first made these pieces from stainless

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    Then weld everything in place

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    Using a grinder I reshaped the part, drilled and threaded the post hole (some crazy thread BTW that needed a special tap). And you get this.

    [​IMG]

    Her is a shot of the Scott damper with the arm I used

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    OK, time to put it all together! And check for any issues before we continue. Those are the stock risers I through on just to check for clearance.....Clarence.

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    Now with the Scott damper installed

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    All fit perfect on the first go! This is the power of computer modeling. If it fits on the screen, it will probably fit in real life. No guess work. Man, when you turn that Scott damper all the way to damp, it is SO hard to move the front end. Very cool to see. And as we will see down the road, the "brass" look of the damper will come into play for the theme.

    If there are any question on any of this so far, please ask away.

    Next the risers, bar clamps, and various dash mounts.
    #81
    mrsdnf likes this.
  2. Wallrat

    Wallrat Been here awhile

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    Would you consider adopting a 37 year old? I'm house trained.
    #82
  3. Captain Excellent

    Captain Excellent Stay weird, or you'll be normal like everyone else

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    +1 on the photos.
    So having made the adaptor for the damper as a separate piece, I can see you were able to sort out some of the design issues. However it occurs to me looking at your last photos, this could have been integral with the top triple like the risers were. Would you do it that way next time?
    #83
  4. sarathmenon

    sarathmenon Armchair Adventurer

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    Man, after the hours of designing, fine tuning and cursing, all those beautiful accents you made are now hidden by the damper. It sucks because those two pieces are truly a work of art, more than engineering.

    Also, are you running any bar risers in your setup? You had the freedom to design your triple trees, so I guess you may have factored that into the yolk itself. The end product you have looks cleaner than the stock setup :clap
    #84
  5. AK650

    AK650 Long timer Supporter

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    Awesome thread, and great machine work. Thanks for posting, and keep it coming....... photos included!

    Jeff
    #85
  6. Motomochila

    Motomochila Moto Scientist and time traveler

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    Fin, why did you opt to build you own Scott's mount instead of using their under mount? I've experimented with different arm lengths and placements similar to your configuration. With off-road trials I found the arm extended away from the damper tended to provide better performance. It was far less on the set up you did here.

    Since you are capable of designing and building anything, :clap, why not consider mounting the Scott's damper down on the fender, since the top mount is so pretty. It can be done quite easily and you are more than capable of the task.
    #86
  7. mousitsas

    mousitsas Long timer

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    Terrific job to say the least :freaky

    And a tongue in cheek comment I just couldn't keep for myself....In your opening post you appraise the excellent german engineering of the stock sugar clamps which split open in a crash and then you proceed to fabricate your own super strong (thus non-excellent engineering) billet ones. Maybe you should mill some fail points there? Should I do the same on my own bikes? :lol3
    #87
  8. Nickhob

    Nickhob Armchair adventurer

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    Maybe I could tag along as the twin brother, though I'm not sure my wife would vouch for me being house trained :D

    Amazing work Fin333, it's like watching a work of art being created :thumb truly fascinating.
    #88
  9. Camel ADV

    Camel ADV Long timer Supporter

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    Very nice work!
    #89
  10. FinTec

    FinTec Been here awhile

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    Yes, as long as you are in your 20's, gymnast, like changing the oil on bikes/trucks, and cleaning shops. Wait, you're not a guy are you?

    Yes, I actually thought of this as well when I was modeling it. I could have just made a "boss" on the triple clap to take the Scott damper. However, I decided against because of several reasons:
    • Not sure if would be using the Scott damper. Might need to change to a different brand and thus different mount
    • Might run with NO damper. Then have this extra boss that did nothing.
    • Extra machine and material. To include this feature would have made the entire upper triple very tall to start with and would be a crap load of machining and an expansive piece of aluminum.

    I have to say I am not familiar with the "under mount" style. I looked on Scott's website and could not see this? Do you have a picture of this we could see?

    Not tongue and cheek at all! And I wondered if anyone would question that. It is a legitimate question. But here is my rational for what I made:
    • There is NO way I can match the computing/engineering power of BMW on those triples. It is a masterpiece in the sense of balance of materials, cost, and strength.
    • I don't have the testing capacity to confirm a triple I make will break as needed.
    • If I just went ahead and made a guess in my design to have it break and could not support the design with testing, then it would be more of a risk as the clamps could just fail in normal use.

    So considering all the above, it was safer for me to just "over build" them and call it done. The fact of the matter is if I get in an accident with this bike the frame bending because the triples did not break is the least of my worries. But if the triples failed during normal use because I DID try and deign them to break in an accident, then I have a big problem. Hope this make sense?
    #90
  11. mousitsas

    mousitsas Long timer

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    Absolutely Finn and this is exactly what I would do (if I only could) myself.
    Now, go on with your fine work! :clap
    #91
  12. 97707

    97707 Vulture capitalist

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    Beautiful job on those machined parts. Its gonna be interesting to follow this build all the way. I wonder if you'd entertain a couple of questions.

    For someone wanting to do this conversion to WP forks, would it be possible to take a stock set of BMW clamps and bore them out, or would you have to remove too much material?

    Keeping the stock 210mm distance between fork centers, but given a larger fork tube diameter, seems like the measurement for hub width will be reduced. Are you using the stock F800GS front wheel, or going to a narrower one?

    What about mounting the brake caliper? Are you going to have to manufacture a custom part to achieve alignment?

    Are the axle diameters the same, or do you need to modify the axle hole in the fork?

    Or would it be better to use the KTM wheel hub/ brake disk and caliper setup that the forks were designed to work with?

    Looking forward to your next set of posts.
    #92
  13. Motomochila

    Motomochila Moto Scientist and time traveler

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    Hey Fin, Same question for me on the 4860's. Since a single mount for caliper, I'm assuming you did the 300 mm 690, or super moto conversion on the front brake. Is the bike stopping enough for you? I looked at the 990 forks as an option. It runs the 4860 fork but is only 210 mm travel. Caliper mount swap with the SX or EXC fork, (single mount) and possibly a working dual set-up with 277-300 mm travel options.

    Picture of a Flat-Tracker I'm working on with the 4860's up front with dual discs. (sorry only view I currently have), but you might look into this. I think the 800 would be a handful to stop on the street with a single. I might be wrong.....pics yet?
    [​IMG]
    #93
  14. Reaver

    Reaver How Did I Get Here?

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    The 650 GS Twin is a single disc. Negligent weight difference. Longer stopping distances and not as powerful but more than adequate.

    Avoid large stationary objects. Brakes only slow you down anyway.
    #94
  15. Motomochila

    Motomochila Moto Scientist and time traveler

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    Might be true here as well unless Fin loads up bags and gear. I have a couple of friends who ride the 650 loaded. we either leave them far behind or out front due to them always seeming to poke us in the backside more ofter than we would like on a quick stop. They're not the best stoppers for sure.
    #95
  16. AK650

    AK650 Long timer Supporter

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    Having withdrawals Fin, more machine porn please!:D

    Jeff
    #96
  17. FinTec

    FinTec Been here awhile

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    Ha, got ya hooked!

    Will try for more updates in next few days and answer the questions above.
    #97
  18. FinTec

    FinTec Been here awhile

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    So might as well take a break from the top stuff (bars and risers) and come back to that later. Well show you what we did for the front wheel and brake. Some answers first:


    I would not suggest this at all. WAY too risky and not even sure there is enough material to do this (don't have the stock ones in front of me). New triples are needed to do this conversion.

    Went with an entire new front wheel from Woodies wheel works. And used a RAD Mfg hub for KTM's. The stock hub is not very impressive in my opinion. Cast aluminum and powder coated. You also get larger bearing with the RAD hub. I had Woodies use butted Stainless spokes to drop just a little more weight of the front. However, you are right, with the 210mm fork spacing you have to use wheel spacers that match. And Woodies happened to have these when I mentioned what we where doing. So very easy to make the wheel fit. I'll also go over some of the details below with some pictures.

    Nope, this was kinda of a surprise, it was 100% bolt together. But you have to get the right parts. I was imagining all kinds of brackets and such I was going to need to machine, but it all worked out with off the shelf parts. More again below.

    Now that I am essentially an entire KTM from wheel and fork, just used KTM axle. Which is nice and large diameter (I think it was 28mm?)

    Absolutely, all the above and below explains why.

    So just to start off, here is the weight of a stock 300mm front rotor

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    The the weight of the new Galfer 320mm rotor

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    Pretty cool to see good engineering at work. A larger rotor that is 1 lb less weight. I was impressed.

    Then the weight of the stock front caliper (sorry bad lighting)

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    Don't have a picture of the MotoMaster front caliper but it weight in at around 1.6 lbs. Another beautiful piece of engineering. Twice as many pistons (4 pot) and much more rigid in design and weights .7 lbs lighter. Awesome.

    Now the MotoMaster does come with an adapter that lets you run the larger rotor. You can see it here in this shot

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    So we do gain a little there. Also, one thing I noticed when I picked up the stock stanchions they seemed heavy. So weighed those compared to the WP4860s. I was amazed to see they where 1/2 lb heavier. Times two that is a full pound off just in the stanchions. Excellent.

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    I also went tubeless on the front (did myself with a tape method, more on that later). I figured that is another 2 lbs off compared to a tube.

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    Here is a shot with the entire set-up and then with the springs out of the fork to check travel

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    So with just some rough math (and please check it) I believe I saved:

    4.9 lbs in rotors
    1 lbs in stanchions
    3 lbs. in calipers
    and lets go with 1/2 lbs in less fluid and brake lines

    That is a saving of 9.4 lbs. And that is all un-sprung weight. :clap That is what makes a front end feel good. Now take the fact the new Woodies wheel I believe is lighter AND no low fender as it is now a fixed fender up tall, I bet we are talking upwards of 12 lbs total lighter removed from the front un-sprung weight. That is significant.

    If someone could weight a stock BMW800 front 21" wheel (no axle) I will do the same here and we can finalize this number.

    As far as braking power, that seems to be a never ending debate. You can go with the math but I went with this logic:

    • As mentioned the 650GS uses a single front rotor and does just fine
    • I have read/followed many KTM 950/990 threads on the same conversion and they have no complaints or issues.
    • The fact I am using a high quality rotor that is full floating coupled with a caliper with 4 pistons (not 2, of course this does not equate to twice the stop power. The math does not work that way with double the pistons).
    I am VERY confident the stopping power it completely acceptable. My belief is the GS800 has dual rotors because some attorney at BMW made the decision that if they don't go dual and the "other guy" does, they will be liable. I have seen it too many time where the attorneys act as quazi-engineers for "your safety". Make your own decision and own it.

    Of course I will have a real report on its performance later in this build....and you'll hear my opinion on ABS :evil
    #98
  19. FinTec

    FinTec Been here awhile

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    Honestly Motomochila I found all the 4860 where the same. All they do is change the spacer inside them to change the travel you want. The spacer is just a section of tube that took me 5 minutes to cut on the lathe (pics of this spacer back a few threads). So just get any 4860 WP and work it from there.

    Sweet bike! With the chrome wheels and red/white/blue theme it looks like something Evil Knievel would be jumping over buses!
    #99
  20. FinTec

    FinTec Been here awhile

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    Oh, here is the magic list of parts you need to make the KTM wheel and MotoMaster brakes all just bolt together.

    The key is to order the supermoto versions of these parts. I went with a 2010 690 SM KTM when I ordered these from an online dealer. Here is what you need:

    Front Axle: #75009081000

    Disc Brake Adapter: #75009061000

    Rotor Mount Screws (longer to go with above adapter): #59009062026

    The key is the disc brake adapter. By using the correct spacers we made the wheel fit in the forks. However, the rotor needs to be moved outward the difference of the 190mm fork spacing vs the new 210mm spacing. This is 20mm but divide by two as only one side is being moved, the spacer needs to be 10mm thick. And this one is dead on at 10mm. See in picture below (aluminum piece under rotor). Get all these parts it all just bolt together.

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