R80ST gets the GS Treatment

Discussion in 'Airheads' started by Airhead Wrangler, Dec 24, 2008.

  1. bgoodsoil

    bgoodsoil Dare to be Stupid

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    I gave up on the idea of making the bike lighter. It's a lot easier to add a solid handhold at just the right spot to make handling the weight easier.
  2. fishkens

    fishkens Long timer

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    :lol3:lol3:lol3 I'm glad someone said that. But it's more fun to tinker than to leave things alone, no?

    That was a pretty good summary. There are some globs that we can trim but we're still starting with a 800 - 1000 cc BMW touring motorcycle. What's the best we can hope for, 380 lbs dry? Or thereabouts? But there are times I look at the mid and final muffler on my GS and think that those items are waaaay too heavy for their purpose. Sigh.
  3. igormortis

    igormortis Cafe Reise

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    If you're referring to the HPN Baja, then that's just the R100R muffler with the chrome covers removed and some fancy carbon heat shields added.
  4. igormortis

    igormortis Cafe Reise

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    Like this? Have a look at the Moorespeed site.


    [​IMG]
  5. bgoodsoil

    bgoodsoil Dare to be Stupid

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    I don't think you could get the bike below 400 without ditching the starter & battery. I don't get my bike near as stuck as I used to by simply avoiding spots where gravity is hurting me instead of helping me.
  6. igormortis

    igormortis Cafe Reise

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    Oh, and weight savings? Stay away from the "Best pies in NZ" thread.
  7. bgoodsoil

    bgoodsoil Dare to be Stupid

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    I noticed that Ducati has a 36mm offset on most of their bikes. They're sportsbike triples but they're beefy and made for USD forks. If we could track down the diamater of the tubes and the distance center-to-center on the triples I bet we could find a combination that'd work. If the center-to-center wasn't exactly right the axle would need work and the calipers wouldn't line up with the rotors right.

    A lot of Ducati guys put aftermarket 30mm triples on their bikes for the track and the stockers end up on eBay. I've seen several sets for less that $200..
  8. Solo Lobo

    Solo Lobo airhead or nothing

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    I just looked at Multistrada triples on eBay and they don't look to have a 36mm off-set,
  9. stickerbush

    stickerbush Adventurer

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    I'll take some measurements from my Multistrada later today.
  10. bgoodsoil

    bgoodsoil Dare to be Stupid

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    I wasn't looking at a Multistrada specifically.

  11. Solo Lobo

    Solo Lobo airhead or nothing

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    Gottcha,

    I was thinking about the Multi as it is the closest thing to a Duc dual sport... if those worked it would be much easier to adapt a complete front end.

    Alternately if you can get Duc triples with a 50mm fork leg hole that's another story as my ex-KTM 640 adventure forks would pop right in :evil
  12. stickerbush

    stickerbush Adventurer

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    There is indeed about 35mm offset on the forks on my Multi.
  13. Solo Lobo

    Solo Lobo airhead or nothing

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    What diameter are the tubes?
  14. stickerbush

    stickerbush Adventurer

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    Lower sliders 43mm, uppers are 52mm.
  15. Solo Lobo

    Solo Lobo airhead or nothing

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    Sorry about the noise in your thread AW...

    From what I can tell, all ducati triples have a larger diameter hole in the lower triple as the USD forks are tapered
  16. Airhead Wrangler

    Airhead Wrangler Long timer

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    further research on potential for weight reduction
    Work in progress:


    R100GS front end:

    Forks with triple 26.3 lbs
    Front wheel 13.4 lbs
    Axle .9
    caliper 2.75 lbs ($822.25 on maxbmw!?!?!)
    rotor 4.59 lbs
    rotor bolts (4) .6 lbs

    total excluding small fasteners: 48.54 lbs (yikes)

    WP 4860 front end w/ ktm wheel:
    used numbers from G450X front end because it's probably pretty close and I still don't have all the 4860 parts to weigh
    wheel 7.2
    rotor 2.0
    axle .75 (actual)
    fork legs 20.5 (actual weight of 4860 legs with oil)
    caliper 1.3
    bottom triple 2.5
    top triple 1.6

    35.85 lbs total (13 pounds less than a R100GS)



    Other potential weight reductions:
    • Muffler 9.52 lbs, convert collector box into muffler ala Paul Rooney
    • Engine top cover 1.23 lbs (ditch completely or make something minimal out of fiberglass or light gauge aluminum)
    • engine front cover 1.86 lbs (cap off bean can hole and make small cover for alternator and crank mounted ignition)
    • timing chain cover 4.3 lbs (able to cut away over half like this: http://hpn.de/pdf/hpn8.pdf Also, anybody want to tell me why this engine has one of the oil cooler lines attached to the LEFT side of the block?)
    • R100GS subframe w/ PD rack 13.07 lbs -> R80ST subframe 5.11 lbs
    • Airbox, 2.4 pounds, replace with homemade fiberglass or aluminum version similar to this, but with foam filter [​IMG])
    • Valeo or nippon denso starter instead of the bosch. That should save ~5 lbs.
    • Shorai FX14A2-BS12 14 Ah battery - 1.6 lbs instead of BMW battery which weighs 13.7 lbs - 12.1 lbs saved
    • Crash bars and sidestand - 5.8 lbs
    • Oil pan (4.19 lbs) and bash plate (2.44 lbs) replace with HPN rallye sump, probably a little lighter, but not much. I'm not doing this to lose weight. Put a hole in your sump while you're alone in a desert and you won't want it to happen again.
    • Mikuni VM34 carbs instead of 32mm Bings would save 2.0 lbs.
    • Engine block - carve away ribs on either side of starter housing, like stagehand did to the fossa. ~ 1.5 lb of possible weight to lose according to Paul Rooney.
    • Baja designs 8" round headlight weighs 5.8 pounds. I might shelf it for a bit in favor of a DOT legal plastic one at about 2 lbs. 3.8 pounds saved.

      Turn this:
      [​IMG]
      Into this:
      [​IMG]
    I'm guessing I can save about 12.7 pounds on the forks and front wheel, 9.5 on the muffler, about 5 pounds on the engine top, front, and timing chain covers, probably about 6 pounds on the subframe once HPN has reinforced it, maybe 2 pounds on the airbox, 5 pounds on the starter, 5.8 lbs on the crash bars and sidestand, about 1.5 pounds shaving excess metal off the top of the block, 12.1 pounds on the battery, 2 lbs on the carbs, 3.8 on the headlight and 1.9 lbs for drilling the cylinder heads.


    That's a total of 67.3 pounds. ...or to put it in perspective, that's like getting rid of the 6 bowling balls I didn't realize I was carrying around with me everywhere I go. If I were to switch to soft luggage, 67.3 lbs would be a full RTW touring load. It would basically be the difference between riding a loaded bike and a bare one. Wow.
  17. Airhead Wrangler

    Airhead Wrangler Long timer

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    I decided to look at the weight saving issue from the other side - what is my minimum possible weight? There are plenty of things on the bike that cannot be lightened without compromising safety/reliability or involve more effort than they're worth. This is what they weigh:

    Frame 28.4 lbs
    subframe 5.1 lbs
    centerstand 3.2
    driveshaft /swingarm w/ bearings and pivot pins 11.2 lbs
    final drive 16.2 lbs
    engine 127.9 lbs
    carbs 4.5 lbs
    tranny 25.1 lbs
    rear wheel 13.0 lbs
    solo seat 5.6 lbs
    battery 13.7

    250.9 Total without ANY front end parts or taking any small fasteners, body panels or lighting into account.


    Rear End Comparison:

    I also got curious about the conversion to the R1100GS rear end and wondered what it would weigh compared to a monolever rear end:

    R1100GS
    final drive 16.7
    paralever rod 1.3
    swingarm 7.8
    drive shaft 5.2
    rear wheel 14.7
    disc 2.0
    caliper 1.8
    shock 10.0

    59.5 lbs total


    R100GS or GSPD
    rear wheel 14.2
    swingarm w/ all bearings, pins, lower boot 6.2
    tie rod 1.0
    driveshaft 4.4
    final drive 17.8
    brake shoes, cam, lever 1.9
    shock 8.4

    53.9 total



    R80ST
    swingarm w/ bearings and pivot pins 7.3 lbs
    driveshaft 3.9
    final drive 16.2
    rear wheel 13.0
    brake pads, cam, lever 1.4
    shock 6.3

    48.1 total




    HP2 just for curiosity's sake
    final drive 17.4
    swingarm 9.6
    paralever tie rod .9
    rear wheel 11.3
    driveshaft 4.8
    rear disc 2.1
    rear caliper 2.1
    shock 4.9 (I find that very hard to believe)

    53.1 lbs total


    It looks like the monolever, despite being heavy as hell, may still be the lightest shaft-driven rear end BMW has made to date.

    I also realized I could save 1.6 pounds by going with 1000cc jugs/slugs rather than 800cc ones :D
  18. Stagehand

    Stagehand Imperfectionist

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    :lurk

    I'd be curious if any of the three driveshafts I know of (Stock, HPN and the Emerald thing) are different, weight wise from each other.

    WOnder if any of the other bits could be made out of different materials for any gain. Doesnt really seem like it.

    Also, where did you find those numbers? Did you have all those parts to disassemble and weigh, or did you harvest info from the little dog lover?
  19. Airhead Wrangler

    Airhead Wrangler Long timer

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    Max lists weights on their parts fiche. Little dog lover?
  20. Stagehand

    Stagehand Imperfectionist

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    InfraCaninophile. :D lover of little dogs.

    I have been looking at Max's fische since it began, and dont know how I ever missed that.

    Tunnel vision! WHOA!