Frame mounted skid plate for bmw r100 gs?

Discussion in 'Airheads' started by oldbmw, Apr 18, 2013.

  1. oldbmw

    oldbmw havehandlebarswillrideit

    Joined:
    Feb 2, 2008
    Oddometer:
    253
    Location:
    Reedley, CA
    Does anyone build a frame mounted bash plate for a bmw r100gs?
    I have the oil pan mounted set up.
    Thanks for any ideas.
    #1
  2. hardwaregrrl

    hardwaregrrl ignore list

    Joined:
    Jan 26, 2006
    Oddometer:
    8,144
    Location:
    Atlanta
    Talk to Prutser about this. He has made one for his R80ST. There isn't one on the market, so you'd be a pioneer.:1drink
    #2
  3. oldbmw

    oldbmw havehandlebarswillrideit

    Joined:
    Feb 2, 2008
    Oddometer:
    253
    Location:
    Reedley, CA
    Okay. Thanks for the lead.....
    #3
  4. oldbmw

    oldbmw havehandlebarswillrideit

    Joined:
    Feb 2, 2008
    Oddometer:
    253
    Location:
    Reedley, CA
    No reply from Pruster but I do have an idea. If you weld angle iron tabs on bottom of frame rails, you can remount your existing skid plate. A friend and I built a skid plate for a 1971 XS 650 I rode in the Barstow to Vegas Dual Sport event this past Thanksgiving. It took a beating but save my cases on a bike that had 3 inches of suspension travel. I think I will go this route. Then, the impact of rocks and boulders etc. don't transfer to the oil pan.
    #4
  5. bgoodsoil

    bgoodsoil Dare to be Stupid

    Joined:
    Jul 9, 2008
    Oddometer:
    4,673
    Location:
    Washington, DC, USA
    A frame-mounted bashplate would be difficult with GS headers since they run almost under the frame tubes but with any other header it should be doable.

    It's still a 3" drop from the frame to the sump. Even if you get it rigged you'll have trouble making it strong enough not to move without making it weigh a lot. I looked into to this once. I could've gotten a plate hanging off the frame but I'm pretty sure it'd get mashed into the sump in a hard impact. Let us know if you figure out a solution.

    I've got big chunks of rubber matting behind my sump-mounted bashplate to soften the blow. It might be a more realistic solution for you. People have been bashing these bikes over all sortsa things for a long while with sump-mounted plates. I wanted to mount a plate to the frame too but the sumps seem pretty stout.
    #5
  6. naginalf

    naginalf Handy Schtroumpf

    Joined:
    Jan 29, 2010
    Oddometer:
    418
    Location:
    Madison, WI
    I have an idea. Transmitting the force of an impact to the frame is not necessarily the goal here, it's simply to reduce impact onto the oil pan. Even with the bash plate mounted an inch away from the pan, that may make it even more susceptible to impact damage when the aluminum bash plate, with no cross grain support like it had with the oil pan, will be more likely to crack instead of bend and force jagged edges into the pan. I don't think we would need to connect to the frame to deflect damage better. Perhaps if one were to cut out the proper size of plate, rough up the inside surface of the new plate and the pan's existing bash plate with 50 grit, position the new plate about a 1/2 - 1" away from the pan, then fill the space with soft polyurethane. You could drill holes and insert a tube/pipe to make cutouts for pan bolt access. Impact absorption would be excellent I'd imagine, much better than a plate with nothing but air behind it. What do you think?
    #6
  7. Warin

    Warin Retired

    Joined:
    Aug 30, 2012
    Oddometer:
    3,393
    That is an excellent way of reducing the oil cooling on yer bike. :lurk
    ------------------------------

    The earlier R80G/S bash plate was formed into a corrugated shape with some cooling/water shedding slots in it. And it bolted directly to the sump.

    You could mount an extensive bash plate to the font of the frame and to the bottom of the foot peg mounts. Use some rubber bump stops between the new bash plate and the sump to aid strength and stop ringing. Something at least 3mm thick?

    The idea is to spread the impact over a large area - so you don't get a sharp puncture through the sump?
    #7
  8. Prutser

    Prutser Long timer

    Joined:
    Aug 5, 2012
    Oddometer:
    1,335
    Location:
    The Dutch swamp

    Sorry about that. I didn't check the mailbox for a few days.
    I made some plates and mounted them between the frame and the engine.
    They are mounted on the 2 12mm engine studs. I use the plates to mounth the skid plate to.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
    #8
  9. bgoodsoil

    bgoodsoil Dare to be Stupid

    Joined:
    Jul 9, 2008
    Oddometer:
    4,673
    Location:
    Washington, DC, USA
    That's the coolest bashplate I've ever seen ever. :thumb

    Any chance you've got pics of the plates where they come out beneath the exhaust? I'll warn you, if I see those pictures I'm stealing this idea :D



    The later bikes dropped those cooling fins anyways. To be fair they added an oil cooler but I know a lot of people that ditched the oil cooler on their r100 many miles ago with no issues.
    #9
  10. Prutser

    Prutser Long timer

    Joined:
    Aug 5, 2012
    Oddometer:
    1,335
    Location:
    The Dutch swamp
    Sorry I don't have more pictures of the plates. I welded some plates under the plates that are clamped between the engine and the frame. Than bolted the bash plate onto those plates.
    The bash plate is 4 mm free from the sump. And it still is after landing the bike on the bash plate trying to jump 70cm thick tree trunks. :loco So far I have no problems with overheating.
    #10