airhead off road suspension?

Discussion in 'Airheads' started by Ras Thurlo, Jun 21, 2011.

  1. Ras Thurlo

    Ras Thurlo Desert Lion

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    Does anyone have experience in upgrading airhead suspension for real off road use?

    I assume some of you have tricked out airhead dirtbikes

    I have a paralever 80gs which I use as a dual sport bike on conti tkc's.

    the tractor pull is great and as long as you avoid mud with those tyres - it can get you through far more than it should.

    Have got into it enough that I now wanted to move on from the soggy stock ride
    #1
  2. Solo Lobo

    Solo Lobo airhead or nothing

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  3. Rob Farmer

    Rob Farmer Long timer

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    I'm lining one up as my next project.

    I have a few sets of WP USD forks from 640 KTM's in my stash, getting them to fit the GS is pretty straightforward.

    The stem simply presses out, took around 5 tons of pressure on a press, it's then just a case of machining the KTM stem down to take BMW bearings. before pressing the stem back in.

    This is my mock up and a long way from what the bike will end up looking like. The frame will need bracing before I use the bike.

    [​IMG]

    If you want it done well then have a look at Richie Moores website http://www.moorespeed.co.uk/aircooled-bmw-gs-improvements

    I want to ship my frame to Richie for the bracing work. Looks like this when it's done.

    [​IMG]

    Shurv has posted his rebuild using Moorespeed parts and services http://www.ukgser.com/forums/showthread.php?t=247228
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  4. Lornce

    Lornce Lost In Place

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    1100/1150 swingarm/rear end?

    We appear to be headed down a similar garden path, Rob...


    :brow
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  5. Rob Farmer

    Rob Farmer Long timer

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    How far have you got with it Lornce? What are you doing about the offset in the rear wheel?

    Ideally I'd have liked the 1150 swinging arm driveshaft/Swing arm because it's shorter but the 1100 parts came up at the right price.
    #5
  6. airheadpilot

    airheadpilot Le Poulet du D├ęsert

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    Something I've wanted to try (but don't currently have a Paralever bike to try it on) is combining the 1150 swingarm with the airhead drum brake final drive. I've seen photos of some of the HPN bikes that appear to have taken this route, and it seems to me that you'd get the central-mounted shock and slightly longer swingarm afforded by the oilhead, but be able to use the airhead GS driveshaft (although you'd probably need to have it extended). Did you look at this at all? I'd be curious as to how easy it is to mate the airhead final drive to the oilhead swingarm.

    Andrew
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  7. Rob Farmer

    Rob Farmer Long timer

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    Andrew,

    I'm not sure what you'd gain by that. The 1100 driveshaft will fit to the Paralever bevel box but you need the adapter at the gearbox end. The whole point of the conversion for me is to replace the increasingly expensive and hard to find drum braked rear wheel for a disk brake and remove the driveshaft failing problem by fitting the stronger oilhead one.

    The paralever bevel box will fit in the 1100/1150 swinging arms but will need a torque arm mounting with an offset. The standard shock will be too short as well.

    Oilhead parts are very cheap at the minute so it makes sense to make use of as many as possible.
    #7
  8. Lornce

    Lornce Lost In Place

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    Still in the parts gathering stage. Have a complete WP Extreme 50 front end from a Husaberg and swingarm/final drive/wheel/disc brake ass'bly from my aulde 1150 carcass. Still need a driveshaft to mod to suit. Haven't decided if I'll use the 1150 rear wheel or lace the 1150 hub to an airhead rim. Those 150 section tires are expensive. :lol3

    Primary reason for doing it is to raise ride height and use the taller oilhead 2.91 final drive. 3.09 airhead gears are rediculously short for a healthy litre motor, imho.
    #8
  9. Airhead Wrangler

    Airhead Wrangler Long timer

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    If you think 3.09 is short, try a 3.36. Yeeesh.
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  10. Stagehand

    Stagehand Imperfectionist

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    I'm not sure what you guys mean by "offroad" I think it means something different here than it does elsewhere. If you'd like basic endless dirt roads and long highspeed desert stuff, a front end thats adjustable on the fly and increased wheelbase with a long rear end and stiffer braced frame is all good... but if you are talking about non-touring tight stuff, where the traction pattern of the tire will actually make a significant difference you have a different path to go down.
    #10
  11. Rucksta

    Rucksta SS Blowhard

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    I'm interested.

    More on your thoughts on "non-touring tight stuff" setup.

    I've been keeping the wheelbase short so the bike will turn and the supension low enough so I can still get on and off to open gates, high enough to clear logs, soft enough not to skip on bowling ball sized rocks and stiff enough to handle jumps and power sliding sweepers.

    Conflicting compromises all then add in strong enough to take the punishment and light enough to be handled and it all gets pretty hard to make a good choice even if I had unlimited $$$$ to throw at it.

    I haven't mentioned brakes yet :D
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  12. Ricklesss

    Ricklesss Go soothingly on the grease mud...

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    To me, "off road", mean's lowwwww gearing...I've got a 32/9 (3.56) rear drive on my /6 g/s, and if you can hang onto it, it will climb up and over most anything. It's especially good for crawling over downed/stalled riders in front of me.:evil
    It supposedly still has a 90mph top end, though I've never tried. I like it.
    RicklessssssS in Oregon
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  13. Stagehand

    Stagehand Imperfectionist

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    Wrote something, but got booted in last night's site maintenance.

    What I basically said was I guess I need to ride one of these WP'd 1150 swingarmed bandits to see if they really do better than significantly better for what I want to do with them, which isnt necessarily Dakar stuff. A steering damper alone did more for me than an entire frontendectomy.

    SO I am saying I shouldnt have spoken out of turn, because I dont actually know how good those expensive modifications really are. Dont get me wrong, I am the first one to pour stupid money onto projects already burning, but I need to get out more.

    Speaking of which, Rucksta, if thats your kind of riding, I want to ride with you :D

    I kind of want one GS to keep relatively stock like mine kind of is, and I want another to trick out like crazy.
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  14. Rob Farmer

    Rob Farmer Long timer

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    They aren't expensive options. The whole front end on my bike in the picture cost less than a new pair of stanchions for the standard front end and thats with the brakes and master cylinder. PYCymu, an inmate here, gave me another front end the other day. If the parts are cheap it's worth trying? If it works well I'll be buying a set of Gletter yolks.
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  15. Lornce

    Lornce Lost In Place

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    I could barely stand that at 800cc. At 1000cc? No way.

    :nah
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  16. Lornce

    Lornce Lost In Place

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    You've got me curious Stage, because I can't imagine how a GS would/could possibly benefit from a steering damper? :dunno

    :scratch

    I've pushed the aulde PD through some fair decent "extremes" over the years and have had moments wishing for less weight, better traction more suspension or greater ground clearance. But never, ever have I felt a need for a steering damper.

    What's up with that?

    :ear
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  17. adiablolex

    adiablolex Lost again

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    only time I thought I coulda used one was when doing less than 80km/h in 2' deep sand.
    This was on a lighter bike with better traction, more suspension and greater ground clearance...:lol3
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  18. Rucksta

    Rucksta SS Blowhard

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    Stage. I've watched your exploits on the GS and also though I'd like to ride with that guy he seems to know how to have a lot of fun.

    I've considered a steering dampner but got used to the mild headshake as the bikes way of telling me to ride more agressivly.

    I've gone long on the front and rear 265/210mm on a shorter than stock wheeelbase. I only use 210/170mm of travel but its nice to know I'm not approaching the limits.

    The suspension mods changed the bike to allow selection of gear and throttle to choose power delivery rather than gear for speed to match the front end performance to the terrain.

    Pretty much the bike is a 3rd gear proposition with second being for cautious apprasial of what lies ahead and 4th for open sections of forest where the response from the power and torque of 4000+ rpm is not called for.

    5th is transport and hooning but 4th is still good for hooning on dirt roads. A taller 5th is on the menu. 1st is for getting it wrong or wusssing out.:D

    Bike still does "Dakar" really well but not as good as a long driveshaft long wheelbase bike but well enough to see of all but the 950SEs, HPNs and the occasional well riden ADV990.

    For the extra high speed stability and luggage /load balance options of the longer swing arm I've decided to pass cause I'm not that fast anymore and I'm a credit card camper prefering pubs and a mimimal payload on the bike.

    So how is this related to the original post?
    My experience is franken bike conversions are a good thing but full blown "Dakar" type conversions may not be appropriate for all riders and riding conditions.

    I went duc hunting (rare for me to enjoy sealed roads) a while back with a bloke on an HPN frame / suspension and the 1040 motor.
    He was clearly faster on the top end when the 336 cam kicked in but the roads we were on were more suited to mid range and a more nimble set up. Turning, braking stability and power on exit were more important on the day.

    We both enjoyed ourselves, picked up a couple of scalps and got some ideas re alternate setup on our bikes.
    #18
  19. Stagehand

    Stagehand Imperfectionist

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    I dunno. Every little bike benefits from them, I dont know why a big bike wouldnt. Cross ruts at anything more than 40mph will tear your arms off, and a steering damper set for kill will pretty much make those go away, and youre left with just the up-and-down problems. Really though, they let me forget about about holding on for dear life and get on with the business of riding. Its extremely confidence inspiring. The rally racing stuff I do occasionally its a godsend and lets you drive faster. I dont know specifically how, other than I now just point the bike and shoot, where I used to snowplow. And I dont get 1/10th as tired holding on. Simply going faster to smooth out the rough spots isnt going to work for somebody at my skill level, I'll just crash.
    This is video of stuff that a steering damper is great for:
    http://www.youtube.com/watch?v=QaXRnxAlwZI
    Granted, this is also the kind of stuff that a larger HPN style bike would be great for. Country Doc can probably back me up on this. He's raced Rallymoto as well, AND is building an HPN.

    Lornce, I swear I'd let you ride mine to try it out, but its got progressive front springs and heavy fluid, so I know you wouldnt like it. :D THe rest of the forks weight and lack of adjustment is their major drawback, but they dont bottom out, dont flex very much with the giant axle and fork brace, and are just butch as hell, like lifetime forks. I can somehow feel the purist in me, meek tho he may be coming out when I think of putting Real Forks on my GS. It'd bump me out of the stock class in Rally :lol3 But I dont want to do that, its like gilding the lily or something. I like it basic, with all the more or less original stuff on it.

    Sure it isnt too expensive, but Mr. Farmer, thats only the beginning. A full WP front end isnt so bad and of course, grafting an 1150 rear end isnt too bad by itself either I suppose. Everybody has a different idea for the upper shock mount, dont they? :D same for making a longer single sided swingarm, And then add in frame bracing. On the other hand, adding a steering damper isnt exactly plug and play on an airhead, and you might get a lot of adjustment and a place to hang a damper for the price of goofing around with a stem. and some bearings, and maybe just re-valving and getting the length right. I'm obviously no good at that sort of thing yet.

    THere are definitely times I want to try the HPN style desert long legged warriors and see what they could do, but I also want to see if they are just awkward giraffes in the back woods, or if they go another way.
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  20. davorallyfan

    davorallyfan Commonist

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    Ruksta Stage room now. :freaky

    Long distance romances never end well.
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