Ontic's 1981 R80G/S build-up thread

Discussion in 'Airheads' started by ontic, May 24, 2011.

  1. ontic

    ontic

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    A small update, part ride report,
    Tank has been repaired and faired and primed.
    Smooth as silk now with not a sign of dents or damage. Final priming and then painting is going to wait until I figure out what I am doing with other things to paint.

    Next,
    I've started collecting bits for my WP 5060 extreme front end.
    A couple of adv'ers replied to my wanted post and I have pieced back together most of the front end of a 1999 KTM 400SX that they parted out between them.
    Last week I went for a drive to pick up the front wheel and axle, with decent knobby tyre and a rimlock. The corrosion on the spokes cleaned up pretty well with some rustconverter stuff and a bit of scrubbing- the wheel is nice and straight and very usable.

    Then a few days ago I left on the R90/6 for a two day one night ride covering about 850km's to pick up the forks and stay over at a friends place and then ride home the next day.

    loaded up bright and early
    [​IMG]

    pretty soon I was riding through temperatures just above 0 deg C.

    later in the day, there's snow on those mountains in the distance but it can't really be seen
    [​IMG]

    finally met up with the adv'er and loaded up the front end (thanks Terry!)
    [​IMG]

    next it was time to ride to a friends place where I made it just before dark. We polished off some of his homebrew beer and an excellent steak and 3 veg meal he prepared, and a full bottle of Mount Gay Rum. Outside the two 1974 R90/6's caught up. Here they are the next morning.

    [​IMG]

    I was feeling a little chilled and bruised from the previous days ride, but off I went again.
    After a bit of rain and very chilled hands again, finally I started to make it close to home and some of my favourite local country and roads.
    Here's a couple of shots in that perfect horizontal winter light, just before riding into another patch of rain,

    [​IMG]

    [​IMG]


    and, after a nice sleep in I re-united the forks and the front wheel.
    Man these things are FAT. Having never consciously noticed them in the flesh before, I was surprised at the sheer size of the things.
    [​IMG]
    [​IMG]

    Next up I need the wheel spacer to replace the speedo drive thing (which I also didn't get)- I have bought one on ebay and will be getting it posted soon,
    Then a rotor and caliper and caliper holder. Still figuring out which way to go with that. This front end came stock with a 300mm rotor but it was not available to me to purchase.
    And hopefully soon a set of R-Dubbs and HPMguys triple clamps which are getting re-made.
    available here.

    Re-springing if required (likely) and re-valving and probably lowering to stock beemer fork height will follow at some point,

    Cheers,
    #21
  2. Stagehand

    Stagehand Imperfectionist

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    great post and pics, Ontic. Mount Gay is one of my favorites.
    #22
    BROTOWNBOY likes this.
  3. Lornce

    Lornce Lost In Place

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    Interesting thread... but needs more weapons.



    [​IMG]


    :evil
    #23
  4. ontic

    ontic

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    Cheers Stagehand,
    it is a great drop indeed. I've got a weakness for good brown spirits of many types, and for a while was quite settled on whiskey, however Mount Gay Rum has become a bit of staple nowadays for my bike rides.
    Only thing is it can be a bit hard to find in some of the backwoods country towns here. And there is not much good to be said about Australian rum IMO. I think I have discovered the pattern- we have a bit of a redneck association with rum here. However, in a lot of country towns, especially redneck ones, not many 'blokes' would be naturally inclined to buy a bottle of booze labled 'Gay':D
    So there's the dilema. In my efforts to buy this spirit in quite a few places it seems to be a case of- a little bit redneck- not so good- they probably like a bit of rum, but not enough to really appreciate it, and thus I can't find Mount Gay anywhere. In a real good sorta-spooky redneck place- counter-intuitively- much better prospects- maybe they like their rum enough to appreciate a good one over a shit one and not care about the lable?:lol3
    I dunno, it is just a theory that seems to play out.


    Lornce,
    Thats a very nice, finely looked after and maintained lump of metal and timber! I'm not much into guns or weapons myself. I have no objection to the them for hunting, for food or necessary pest control, but in my country at least I see little reason for handguns. I do know better than to try to argue this point with someone from North America:lol3
    As far as weapons go, in my thread one will have to be happy with badly wielded tools doing damage to undeserving bike parts, and collapsable fishing rods damaging fish.

    Heres a bit from my 6 week ride over christmas/new year to keep both you and Stagehand happy:evil

    Fishing for trout on the Thredbo River,
    I get lucky,
    [​IMG]

    weapons and ammunition used
    [​IMG]

    Venhill featherlite clutch cables are excellent- especially when they break after a few thousand Km's in the middle of nowhere and you thank your lucky stars that you brought your old one. What they are excellent for is stashing in your pack for later unthreading and using the stainless steel wire to stitch a freshly caught and cured trout to a stick
    [​IMG]

    Of course, for a slow smoke it is nice to have something else to cook up.
    [​IMG]

    Of course, by the time it was smoke up, some bastard had finished the rum.
    [​IMG]

    So, I had to pack up camp, take my trout and find another bottle of brown spirits for my next camp (had to settle for Jamesons in that particular town).
    [​IMG]

    Cheers,
    [​IMG]
    #24
  5. Lornce

    Lornce Lost In Place

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    Fantastic tale and pictures!


    :thumb :thumb
    #25
  6. Sibbo

    Sibbo Been here awhile

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    Jeez Ontic , brilliant mate ! I'm going to have to quiz you about the intricacies of airhead dirt bike construction though .This is all about suspension travel ? How much extra ? What are the ubeaut clamps for ?



    On the subject of headers , have a look at this ....http://www.youtube.com/watch?v=cquCfvsvoq0&feature=player_embedded
    #26
  7. ontic

    ontic

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    Hi mate, thanks,
    I'm far from an expert regarding these intricacies and am purely stumbling my way through things bit by bit.
    It has taken me a long time to develop a plan, and I still haven't finished that plan yet- it is enough to get started though.

    regarding the front end- first some background-
    I was not very happy with mine as it came to me. It was way too soft for my liking, diving hard under braking, and kinda floppy feeling all over, and this was just riding with a small tank and no other loading on the bike. As I looked into things I found that many consider these front forks to be a little underbuilt- especially for loaded down touring.
    Anyway, I looked into improving things. I could have tried for stiffer springs, for race-tech gold valve cartridge emulator thingies, for a stiffer billet upper triple clamp (unlike your 80ST which I believe came with a proper upper triple clamp the G/S one is just flimsy stamped steel), for a fork brace, etc, etc. Some people seem happy with this sort of outcome. This didn't seem optimum for me as I was rapidly loosing my drive to 'keep the bike as stock as possible' and wanted to go for a better end result. Also, things like my G/S front wheel wanting a respoke and general rebuild steered me away from sticking with this front end. Getting it working like I wanted would likely have been very expensive.

    Next I started heading towards doing a GS Marzocchi front end swap. These have a much better reputation and are considered by many to be a good bang-for-buck plug-and-play upgrade. Of course, unless I wanted to work out custom axles and whatnot to fit my G/S wheel (which still needed work), the whole front end from a GS is required, wheel and all- and this too was looking to be very expensive to source. Also, it was looking like to get the most out of these forks a re-spring and gold valve might also be a good idea. More $$$. I did start going down this route though and came a hairs breadth from buying forks from German Ebay which fell through at the last minute.

    After a lot more reading and gradually overcoming my trepidation to attempt anything greater than a simple 'plug-and-play' option I decided to go for a WP Extreme 50mm conventional fork swap.
    The timing of this decision concided nicely with Solo Lobo having started his Unholy Union thread
    http://www.advrider.com/forums/showthread.php?t=676340
    and he has been a great help through many PM's in talking me through this:deal

    While I have largely overcome any inclination to keep this G/S stock, or even 'bmw' in all its parts, one thing I haven't managed to get over is my aversion to USD forks on an old airhead like this. It is silly, but they just look wrong to me, and conventionals just look right...
    So, the 50mm WP's seemed like a good workable option. Of course the net is full of opinion going in just about any direction you could want- but there seems to be a fair few people who think these forks are some of the best conventional forks ever made... I don't know about that, but at the very least they should represent a significant enough upgrade to start to justify the money that was going to be spent on any option. They will need some tuning and re-working, probably new springs and re-shimming the valves.
    But, they are reasonably modern big stiff forks with adjustable compression and rebound.

    At first I plan to limit the full extension of the forks to keep them at the stock bmw height in order to maintain the 'right' geometry. This is a relatively simple operation of changing spacers inside the fork and is completely reversable. Solo Lobo goes over this in his thread.
    Later, if I wish to extend the swing arm, then I will re-extend the front forks. I have no rush on that and plan to get it well set up at stock height first. If I extend the rear it will mean re-springing my Ohlins rear shock and also changing things like centre and side stands, so I want to be sure I want to go that route. That may be round two of the build.

    Now, those ubeaut clamps (the R-Dubb ones right?) are for fitting these forks to the bmw. With a bit of work (again gone over in Solo's thread) it is possible to use the KTM triples, but these have much smaller offset than the huge 38mm bmw offset. Using the R-Dubb triples allows one to basically preserve the same bmw steering geometry.


    Anyway, there is the background and the justification. All up this front end is going to be expensive (a bit more than the other two options), but so was the rear shock, and the rear shock upgrade deserves a good front end upgrade!
    This will be the first time I have tried anything like this, so aside from hoping to gain some significant performance improvements, I am also just in this for enjoyment and experience to see a project like this through from beginning to end.
    #27
  8. davorallyfan

    davorallyfan Commonist

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    Any plans to up the berries - they are gutless stock.

    I'm watching your front end set up as I keep blowing up mine.:1drink
    #28
  9. ontic

    ontic

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    I've thought about it but won't be going down that path yet. Once this is all back together and tuned-in well, I will look into it a bit further. If I found a bargain siebenrock power-up kit, of course I wouldn't say no (and I do peruse german ebay for these occasionally:wink:), but, until then I may just wait for these 'berries' to wear themselves out, or my bank account to grow.
    I don't mind leaving that as a good treat to give myself at a later date if I ever grow a little bored with this bike.

    About the front end,
    Cheers, wish me luck :freaky
    #29
  10. Beemerguru

    Beemerguru Beemerguru...G/S guy

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    You always have options with a G/S. Great platform for building whatever you want.

    Yes, you can add the early GS subframe and get the solo seat...works best with the extended swing arm for weight distribution. Strengthen the gussets before powder coating

    Or use the stock G/S set up..get the solo seat/frame from Germany..look on eBay for specific R80G/S parts...they should show up.

    If you have a good welder, he can move the brake caliper castings on the fork lower so you can fit a GS caliper or other aftermarket setup. Must be careful since the aluminum tube can twist if too much heat for too long.

    You've got a great start so have fun trying things until you get what you like!

    http://gregsgssite.shutterfly.com/
    #30
  11. datchew

    datchew Don't buy from Brad

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    Wow

    That's beautiful.
    #31
  12. datchew

    datchew Don't buy from Brad

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    Remember the Alamo!
    Anyone know more info about that type of tank?
    I'd like to start looking for one as well.

    Are these the 20 year later equivalent of the uber-expensive hoske tanks from the /2 era?



    Great thread. I'm enjoying it. Especially the fish cooking and camping. Nothing like homemade tools, especially when used for fishing and cooking!:freaky
    #32
  13. ontic

    ontic

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    Cheers datchew,
    that photo was taken in a special moment in time, I am glad the digital translation has not lost too much of this extended glorious moment. Lots of cold windy riding through some great steep and twisty mini-mountains. Then after riding for a while with the thought in my mind that I would really like to stop and take a photo of this marvelous country the sun finally explodes out its cloudy confines into that golden horizontal glory...
    I pull up in this spot and walk around and soak it all in for a while, then that flock of white cockatoos starts flying around making the noises that only they can do, with that deep dark grey clouds as background- a wet background that I was about to head out of this sun and into.

    anyway,
    the tank,
    I have found it very hard to find any information on this tank that I bought.
    Here is a german forum discussing the sale of a tank like mine (it looks either the same, or more likely IMO very very similar to mine- but is in much better condition than mine came to me)
    http://www.gs-forum.eu/showthread.php?t=24298
    here is a page on Sauer's own site
    http://www.alusauer.de/deutsch/tanks-frame.htm
    That tank with the paris dakar colour scheme looks more exactly like the shape of mine than the one shown on the previous forum does.

    now, price? Well, datchew, because you inquired I'll send you the details of the german auction. I am not sure if these will go the path of /2 hoske tanks- all I can say is they fit very very well and are superbly made.
    For others, IMO it was pretty cheap. A lot cheaper than other HPN/acerbis options I was watching. I think I got quite lucky. I don't know how rare these are, but I suspect they are rare enough not to be well known about, at least outside of a small niche German market. I certainly didn't know about them before I spotted the auction and won the bidding- for once I didn't even come close to maxing out my maximum bid! the photos made the tank look a fair bit worse than it actually was- maybe that explains it?

    If one looked at it as a dollar value for liter capacity gained- well I suspect it was a steal, at least compared to anything I could have bought in my local market:deal
    I for one was very very happy with the purchase.

    cheers,
    #33
  14. datchew

    datchew Don't buy from Brad

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    Hmmmmm. :deal


    Thanks much!
    #34
  15. Sibbo

    Sibbo Been here awhile

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    So Ontic , what are you like at fiberglass mould making ? There is a market mate .


    and mould making is dead easy ....if slow .

    and thanks for the explanations regarding the forks .When I looked at my ST forks and clamps I thought them perfectly adequate and thought the g/s was the same , apparently not .My top isn't that satisfying but is a bit of 5 mm sheet metal ,the bottom is a good looking casting .
    #35
  16. Sibbo

    Sibbo Been here awhile

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    [​IMG]


    I have a new desktop ! :norton Thanks Ontic ! A good reminder of why we ride .
    #36
  17. ontic

    ontic

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    Ah Sibbo,
    thanks mate, if you are going to honour the image by sticking it on your desktop I'd better email you the hi-res version. It will be on its way soon.

    About the fiberglass mould making- for the tank you mean? I never thought of it, but... I am now thinking of it... easy you say? I think I have read through a thread somewhere about mould making for a tank. The person doing it had crazy skills and it seemed a bit involved if I recall correctly. I'll have to do a bit of googling and look into it. Once the mould is done how easy is it to knock out reproductions? I don't think I got that far in the thread I read:lol3
    Could be an interesting project. I wonder what the copyright issues are though?
    #37
  18. Sibbo

    Sibbo Been here awhile

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    Mate , this is one of my all time favourite sites , a super economical aerodynamically faired 125cc Honda .:norton:norton.Maybe not quite your cup of tea but my motorcycle interests are eclectic .About half way down are a series of good shots of the fiberglass moulds he made for his fairing .Enjoy !

    http://www.velomobiel.nl/allert/Recumbent motorbike.htm
    #38
  19. ontic

    ontic

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    Interesting link!
    After a bit of googling, and not coming up with all that much that was as helpful as the original thread I remembered, I finally found this same thread I read most of quite a while ago.
    Anyway, it is a very thorough (and long) excellent write-up of making a carbon fiber tank from moulding/copying another tank.
    http://www.bayarearidersforum.com/forums/showthread.php?threadid=145975

    Time to have another read through it.
    #39
  20. Sibbo

    Sibbo Been here awhile

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    Good one ...I'll read it tomorrow .
    #40