Fitting a '91 R100GS with an HPN Tank

Discussion in 'Airheads' started by Box'a'bits, Sep 10, 2010.

  1. Box'a'bits

    Box'a'bits In need of repair Supporter

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    Okay, I've just imported an HPN 43l Tank to put on my 91 R100GS paralever. I am aware that you need to modify things to make this fit. Tell me (or better yet show me) what you have done. :D

    Here's the thread on where we've gone with this bike so far...

    Cheers, Steve
    #1
  2. Padmei

    Padmei enamoured

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    It'll never work. You shouldn't have bought it. Best get rid of it before it starts to annoy ya.
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  3. fishkens

    fishkens Long timer

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    My experince is a bit different since I put the 43 l tank on my 88 GS (it didn't have the plastic bits and "roo" bars making the fairing.

    1 - install three brackets that come with the tank (two front and one just in front of the tool trak
    2 - relocate oil cooler to central spot in front of the gas tank.
    #3
  4. fishkens

    fishkens Long timer

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    Whoops, hit enter...

    3 - Use bracket from BMW to mount oil cooler to frame
    4 - Oil Lines? Back in 1991 I had to scrounge 'em up from Earles along with the fittings. Touratech or BMW can be a source today.

    Hmmm, other items:

    5 - Your fairing. I can't say how you'll need to modify it. My minimalist tendancies would be to sell it on fleabay and install a headlight and electonic gauge system of some sort. Hopefully you'll get better advice on that.
    6 - I reommend replacing the nuts that secure the gas tank with metric wing nuts. Should you need to remove the gas tank to access spots underneath it this will save some time. (It seems that I remove the gas tank frequently...for fun).

    That's what I've got.
    #4
  5. Airhead Wrangler

    Airhead Wrangler Long timer Supporter

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    You'll need to modify your seat to fit it as well. It will involve cutting into the seatpan. On the upside, you could lose about 20 pounds of high up weight by getting rid of your fairing, roo bars, head light, gauges, etc and replacing them with a light weight dirt bike headlight and a trailtech or similar electronic instrument set. If you don't go that route though, you wouldn't be the first. Others have made it work:

    [​IMG]
    #5
  6. Box'a'bits

    Box'a'bits In need of repair Supporter

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    Others have made the roo bars work, by adding 7cm (?) into the bars. The fairing also needed to be trimmed. Here's an example on a R80 Basic (from the UKGSer site).

    [​IMG][​IMG]

    Still be interested in others comments, particularly those that have done this. Once you start cutting things up its hard to go back.

    I've also considered losing the fairing (the original plan) & using an R100 8" headlight, with electronic speedo.
    #6
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  7. nowhereman

    nowhereman I'm lost -don't follow me

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    I have been considering getting the tank too, but in my case I was going to sell off all the old stuff (PD tank, fairing and dash) and going with a trailtech or soltek lighting setup and either an IMO 300 or something else for all the engine info. But then there's the seat issue, oil cooler relocation, etc.

    Now if I could convince myself to drop the change on all that (feels like I'd be into it for around 2k after all the stuff is bought) and convince my wife the banker - nah never mind.

    If you don't want to cut up your seat, you may find one still available at touratech. They used to sell them, but they're spendy.

    Forgot to add - here's photos of my favorite HPN tank / gauge set up. You can get the whole shebang from africa queens in germany.

    [​IMG]

    Here's the dash board / gauge tree

    [​IMG]
    #7
  8. fishkens

    fishkens Long timer

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    A Corbin seat also fits w/out modification. The code on the bottom of my seat pan is GS9.3CDS<GS9.3CDS>. I like this saddle because it doesn't have the lip at the front that stock saddle has.

    http://www.equinoxmc.co.uk/index.php?main_page=product_info&products_id=138
    #8
  9. fishkens

    fishkens Long timer

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    Wrangler - Is that a Fox shock on that bike? Do you know if it's still working?
    #9
  10. Airhead Wrangler

    Airhead Wrangler Long timer Supporter

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    Not my bike so I can't say for sure, but it does look like one. The owner of the bike seems to have disappeared in the middle of a long trip to south america.
    #10
  11. Box'a'bits

    Box'a'bits In need of repair Supporter

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    Okay, decided to ditch the '91 R100GS OEM fairing & go with an 8" light.

    Test fitted tank to the bike & (as expected) I will need to trim some of the frame fittings & relocate where some of the electrical items are fitted. I'm keen to see how others has dealt to that. The relay space I have currently filled with a heated grip controller & enduralast regulator, which I now need to re-house.

    [​IMG]

    Thanks for any helpful comment you can make.
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  12. Uncle Pollo

    Uncle Pollo Bad Hombre

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    omfg

    [​IMG]
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  13. bmwloco

    bmwloco Long timer

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    My Acerbis 44 liter (now the HPN methinks) was on my R100GS back in
    '93 when I was riding the US, NZ and Oz.

    After a lot of thought, I just did away with the oil cooler. Mind you, I did that 9 months before I set out on my 9 month journey. It was never an issue. It also made service and maintenance a hell of a lot easier.

    Still have this tank; it is going on The Beast (picking up in early October)
    [​IMG]
    #13
  14. Daithi

    Daithi Destination Unknown.

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    Hi, could one of you gentlemen post a photo of the longer hoses going to the new cooler position, I've the
    cooler pushed out of the way to fit the tank but I don't have the longer hoses/mounts etc.
    [​IMG]
    I just want to be sure the hoses will allow the cooler to sit in the right place and not foul when I fit a new
    front end, so it's the length of each and a photo of the cooler in position if possible.
    Thanks, Daithi.
    #14
  15. onaXR

    onaXR Druid

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    Cant see a bunch from these shots, but roo bars widened oil cooler in center of the frame behind the frt wheel, some electrics moved from top of frame under tank, and the fairing brackets widened a bit. Oil cooler lines are touratech.

    [​IMG]
    [​IMG]
    [​IMG]
    #15
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  16. Daithi

    Daithi Destination Unknown.

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    Hi, could one of you gentlemen post a photo of the longer hoses going to the new cooler position, I've the
    cooler pushed out of the way to fit the tank but I don't have the longer hoses/mounts etc.
    [​IMG]
    I just want to be sure the hoses will allow the cooler to sit in the right place and not foul when I fit a new
    front end, so it's the length of each and a photo of the cooler in position if possible.
    Thanks, Daithi.
    #16
  17. onaXR

    onaXR Druid

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    Best pics I can get right now.
    [​IMG]
    [​IMG]
    [​IMG]
    #17
  18. Daithi

    Daithi Destination Unknown.

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    Apologies for the duplicate posts, I thought the first one hadn't worked, and OnaXR thanks, that's exactly what I needed. I'll need to get those pipes made up and your photos will help a great deal.
    [​IMG]

    I'm awaiting delivery of a DRz400E front end and will post pics when I've both jobs done. Thanks again.
    [​IMG]
    Daithi.
    #18
  19. bereahorn

    bereahorn Long timer

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    :lurk
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  20. onaXR

    onaXR Druid

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    Come over and put new pushrod seals on mine and we will call it even:lol3.
    #20