Airhead Dakar Rally Bike

Discussion in 'Airheads' started by bromax.ca, Jun 6, 2013.

  1. bromax.ca

    bromax.ca Been here awhile

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    You may know all this already but here are a couple of things I learned welding the exhaust. Keeping in mind I am not an expert on this, or anything else for that matter.
    1. Use those beautiful polished 90 deg. bends (no straight sections on them) rather than the 180 degree bends some suppliers sell with straight sections on them. Those are terrible distorted right at the 90 deg mark and won't match up to pipe.
    2. Make sure the parts all mate perfectly. Easiest to do with a belt/disc sander.
    3. If the parts match perfectly, and you use a TIG welder, you do not need filler material and the welds turn out really nice. Playing around a bit with settings you get full penetration, little heat buildup and beautiful welds. Ideally you cap the ends and purge the inside with Argon, there are lots of u-tube videos on it, but you don't have to unless your in the racing industry.
    It is surprisingly easy, again, key are perfect joints, which goes for almost any welding really. The time you spend making the joint perfect you save ten times over when welding.
    Jim Day, dazzadm and Te Hopo like this.
  2. 2WheelTraveler

    2WheelTraveler backinthesaddleagain Supporter

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    Bromax, your post on Airhead Dirt Bikes ??? reminded me to revisit your build thread. It enlightens me as to what is possible when you set your mind to it.
    Good to see your bike getting dirty.
  3. bromax.ca

    bromax.ca Been here awhile

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    I did log many hundreds of miles on dirt/logging roads and trails so far. The bike is performing really well. I had a lot of oil consumption initially until I made an oil sump holding about 3/4 of a liters of oil, which replaced the flat plate bolted to the sump extension. The difference in oil consumption is positively surprising. Total oil capacity is about 3.5 liters now. I still have lots of ground clearance since I shortened the frame in the front.
    When all 3 fuel tanks are full (30 liters) the bike is certainly a bit harder to pick up off the ground, but with the front two tanks mostly empty, the bike is easy to handle even on small trails.

    image.jpeg
  4. thelegend024

    thelegend024 R80GS 1990

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    Really nice!
    Why did you exchanged the flat plate - with the ring you might have 1L (0.5L additional) capacity comparing the org. Sump which gave you total of 2.5L.
    Only for the consumption and offroad use?
  5. 2WheelTraveler

    2WheelTraveler backinthesaddleagain Supporter

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    The engine was tilted as a result of the frame modifications, see picture in post #177. Guessing, that the tilted sump effected the oil consumption. The revised wedge shaped sump got it close to level again which appears to have helped oil consumption.:hmmmmmdono why though.
  6. Airhead Wrangler

    Airhead Wrangler Long timer Supporter

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    Tilting the engine back effectively raises the oil level at the back of the block increasing odds of oil contacting crank and getting whipped up and slung around (or maybe just slung around by the cam) in the crankcase creating a fine oil mist which gets sucked out the crankcase breather. That'd be my guess.
  7. 2WheelTraveler

    2WheelTraveler backinthesaddleagain Supporter

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    Thanks, AW. I was thinking that it had something to do with the pick-up? So the bottom levelness of the sump is not the issue, it's the oil level, specifically the oil that might be effected by crank. I had been thinking of tilting the engine back for increasing rear travel, and liked the idea of tweaking the frame to avoid having to drop the engine for an oil change. I can't just seem to leave well enough alone.
  8. bromax.ca

    bromax.ca Been here awhile

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    I am not sure why it made such a dramatic difference to be honest. I did not change the dip stick and kept filling to the same level with the plate and the wedge style homemade sump. I did add a spacer to the pickup to lower it. As mention I now have about 3.5 liters of oil capacity. And next to no oil consumption. Don't ask me why. I do a lot of riding in very steep terrain. I wonder if that has some effect. However, not having lowered the oil level, the change in oil consumption makes no sense to me. I am just happy it is less.
  9. bromax.ca

    bromax.ca Been here awhile

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    If you're not living on the edge, you're taking up too much space!?!? I don't actually belief that. However........
    I typical ride on my own since I don't know any other offroad riders in my area. I learned the hard way to bring what I need to get the bike out of most places I may drop it into. I have some 50' of high quality 1/4" line, very strong but light. A 4:1 purchase block and tackle used for sailing, again, high quality (600 lbs capacity) and very light. I have valves on all fuel and breather lines, so I don't loose oil or fuel when the bike is upside down. I have a saw and some cord so I can build whatever I need to lift the bike out wherever it comes to rest. In theory anyway. In this case I was able to get the bike back on that little bridge without my gadgets, however if that rear wheel would have come off, I would spend hours getting the bike back up there. Luckily not even a scratch on the bike or on me.

    image.jpeg
    image.jpeg
    Uke, OM, lucky6600 and 9 others like this.
  10. bromax.ca

    bromax.ca Been here awhile

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    image.jpeg
    OM, Mugwest, Ras Thurlo and 5 others like this.
  11. Uke

    Uke visualist Super Supporter

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    I can see a lot of uses for this, above and beyond rescuing a downed bike in an awkward location.

    Jim Day likes this.
  12. Jim K in PA

    Jim K in PA Long timer Supporter

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    Excellent. Thanks for sharing the challenges as well your successes. We learn from our own, and each other's mistakes. But only if we share them. :thumb
    Uke likes this.
  13. Stagehand

    Stagehand Imperfectionist

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    :eyes
  14. bromax.ca

    bromax.ca Been here awhile

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    I have the bike for sale. See add in the Airhead Flea Market.
  15. Airhead Wrangler

    Airhead Wrangler Long timer Supporter

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    What!?
  16. Derek_S

    Derek_S Been here awhile

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    And for IMO a very fair price.
  17. dazzadm

    dazzadm Long timer

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    If only you were in New Zealand, I would have bought it... I hope it goes to a good home.:thumb Sorry to see you're selling it.
  18. 2WheelTraveler

    2WheelTraveler backinthesaddleagain Supporter

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    Say it ain't so...but if this means another cool build thread I'll get over it.
    Derek_S likes this.
  19. Stagehand

    Stagehand Imperfectionist

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    I wish I could buy this just so it won't be competition.

    Strictly speaking, if I wasn't still in the middle of hemmoraging cash on my own bike, I would find a way to get this one. Not only would I race it, but it would really fill out the garage nicely. Holy crap I was sure I didn't want another bike, after my last one..

    Edit: did you say 3.5 L of motor oil? That's a lot.
    Jim Day likes this.
  20. Jim Day

    Jim Day full manic mechanic

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    I really love this bike as well. One of the best one of a kind builds around. I just hope whoever buys it really uses it. :freaky
    Uke likes this.