R65 G/S Project

Discussion in 'Airheads' started by a_k_nicholls, Nov 6, 2004.

  1. Bigger Al

    Bigger Al Still a stupid tire guy

    Joined:
    Oct 12, 2004
    Oddometer:
    8,011
    Location:
    Auburn, CA
    Sorry about the poor typing. It should be: "A buddy of mine has a plasma cutter and a couple of welders." Kinda tough to get my sausage fingers to type this early in the morning.
    #21
  2. ozadvntr

    ozadvntr Planning that trip, again

    Joined:
    Sep 15, 2002
    Oddometer:
    1,177
    Location:
    Queensland, Australia
    I have investigated a suitable front end to put on a G/S. I was even very close to purchasing a WR400 walk off front end from Mr Motocross wreckers in Melbourne, bolt in with only minor rework to the head stem.

    I have though, optioned for an USD WP set that was fitted to a G/S in Germany. As Greg suggested, I am intending to visit Paul Rooney and have him lengthen the swing arm and harden the frame up a bit.

    I have done a few mods on the engine and other than that it is fairly standard out of the factory.



    Greg,

    Did you have a look at the pics on my web site, a good pic of you and I talking at the fuel bowser at Innamincka.
    #22
  3. ozadvntr

    ozadvntr Planning that trip, again

    Joined:
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    Oddometer:
    1,177
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    Yes,

    There is a GS / BM day in Toowoomba on 21st November. There will be a few GSs on display as well a few road bikes.

    Stu will have his Special there,

    RTO will have the Enogerra Special there if Rooney gets his rear shocks done.

    I also have Paul Rooneys number at home.

    email me at

    tjaeger@optusnet.com.au

    and I will pass it on to you.
    #23
  4. Malindi

    Malindi Zen Adventurer

    Joined:
    Jul 9, 2001
    Oddometer:
    5,422
    Location:
    Vancouver, BC
    I built up a G/S a year or so ago. Here are some pics of the frame modes:

    Rear shock frame mount
    [​IMG]

    The upper tubes:
    [​IMG]
    #24
  5. Stagehand

    Stagehand Imperfectionist

    Joined:
    Oct 6, 2004
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    Location:
    Shawangunks
    Some more notes--- My anecdotal sources say that swingarms do not come in different lenghts. the /6 swingarm is longer by 2 inches than the /5's. You can see where BMW welded more tube to the swingarm to make it longer. So making swingarm longer is no problem. I guess you just do the same on the left hand side, to hold the axle. To make a longer Driveshaft, the best idea I have heard is to cut it in the middle, and weld a longer piece into the middle. I've not seen it done, but it should be possible. It would have to be spin-balanced, so as not to eat itself apart.
    The Exhaust pipes can be run Over the cylinders, and routed out the back, for clearance. Of course, these will haveto be custom made.
    Some have added Frame stiffeners from the swingarm pivot area diagonally up to the steering head area.
    Also, the R65's had a shorter cylinder head, and it was higher on the crankcase than the other models, so this might be the best starting engine, sothis contributes to high clearance.

    Front End-- Almost all Dirt bike front ends are longer in the steering head than the BMW's, for the obvious support it provides, and this is where the machining takes place, to make up this distance. My anecdotal source says this procedure is a matter of finding all the parts that fit. Not too harsh a task.
    Changing the angle of attack on the drive shaft is something I have not heard a good idea for, nor do I have one. Best estimates says 30-40K, before failure.

    So-- we got to talking, me and my mechanic. He's saying that on the ISDT BMW 1973 bike, which we are using as a sort of model, they got rid of the starter and charging system altogether. He said it would run 4-5 hours on a full battery. That means they removed the starter, shaved off the engine casing that holds it. Removed the Airbox and Diode board and leveled it off above the crankcase. then removed the alternator and front cover, and just made a cute little cover for the front of the crankshaft, and the ignition thing. the Engine is actually Quite compact. Makes it a small little package. For Starting: The only /6 five speed gearbox with a kickstart was made in '74. BMW only continued the kickstart on the four-speeds.
    Removal of all that stuff would save a lot of weight, and could move the whole engine UP in the frame a few inches. They also saved weight by shaving 10 pounds off the flywheel.
    With the removal of the airbox, the new custom pipes that go over the cylinders could join in that area. I think it means relocating the battery, somewhere. Dont know where. Didnt get that far.
    Some of this is a little farther that I would want to go, but It sounds like it would make a crazy bike.
    I will try to find out more about front end matching. I wonder if anyone has any specifics, if they've done it, yet.
    Having just paid off the last loan, I now need to buy a new enduro. After That, however, I will be accumulating parts to start building this beast.
    #25
  6. Stagehand

    Stagehand Imperfectionist

    Joined:
    Oct 6, 2004
    Oddometer:
    27,296
    Location:
    Shawangunks
    Some more notes--- My anecdotal sources say that swingarms do not come in different lenghts. the /6 swingarm is longer by 2 inches than the /5's. You can see where BMW welded more tube to the swingarm to make it longer. So making swingarm longer is no problem. I guess you just do the same on the left hand side, to hold the axle. To make a longer Driveshaft, the best idea I have heard is to cut it in the middle, and weld a longer piece into the middle. I've not seen it done, but it should be possible. It would have to be spin-balanced, so as not to eat itself apart.
    The Exhaust pipes can be run Over the cylinders, and routed out the back, for clearance. Of course, these will haveto be custom made.
    Some have added Frame stiffeners from the swingarm pivot area diagonally up to the steering head area. Around the exhaust pipes.
    Also, the R65's had a shorter cylinder head, and it was higher on the crankcase than the other models. This contributes to high clearance,
    so this might be the best starting engine.
    Front End-- Almost all Dirt bike front ends are longer in the steering head than the BMW's, for the obvious support it provides, and this is where the machining takes place, to make up this distance. My anecdotal source says this procedure is a matter of finding all the parts that fit. Not too harsh a task.
    Changing the angle of attack on the drive shaft is something I have not heard a good idea for, nor do I have one. Best estimates says 30-40K, before failure.

    So-- we got to talking, me and my mechanic. He's saying that on the ISDT BMW 1973 bike, which we are using as a sort of model, they got rid of the starter and charging system altogether. He said it would run 4-5 hours on a full battery. That means they removed the starter, shaved off the engine casing that holds it. Removed the Airbox and Diode board and leveled it off above the crankcase. then removed the alternator and front cover, and just made a cute little cover for the front of the crankshaft, and the ignition thing. the Engine is actually Quite compact. Makes it a small little package. For Starting: The only /6 five speed gearbox with a kickstart was made in '74. BMW only continued the kickstart on the four-speeds.
    Removal of all that stuff would save a lot of weight, and could move the whole engine UP in the frame a few inches. They also saved weight by shaving 10 pounds off the flywheel.
    With the removal of the airbox, the new custom pipes that go over the cylinders could join in that area. I think it means relocating the battery, somewhere. Dont know where. Didnt get that far.
    Some of this is a little farther that I would want to go, but It sounds like it would make a crazy bike.
    I will try to find out more about front end matching. I wonder if anyone has any specifics, if they've done it, yet.
    Having just paid off the last loan, I now need to buy a new enduro. After That, however, I will be accumulating parts to start building this beast.
    #26
  7. Tanami

    Tanami Under The Weather

    Joined:
    Mar 26, 2006
    Oddometer:
    316
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    Far, Far Away.
    Stagehand...this would be an awesome machine...MAKE SURE you keep us posted when comes to time. My bike retains the starter but has the casings shaved back...for weight and cooling outcomes ...also we toyed with the idea of an oddysey battery on its side under the gearbox where the collector box once was...but for water etc..but could be done..
    #27
  8. a_k_nicholls

    a_k_nicholls Been here awhile

    Joined:
    Oct 8, 2003
    Oddometer:
    291
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    Near Canberra Australia
    Hey Stagehand that really does sound like a wild project, Please keep us informed if this baby ever gets off the ground.

    Also as Ozadvntr said he almost bough the front end off of a WR400 it really shouldnt be too hard to get that part sorted. Swing arms are the other thing I have been putting more thought into, It really would depend on how you wanted to ride this bike as to how long you would make the swing arm & I also thing that the twin shocks could be better too so the swing arm is kinda balanced rather than having all the weight pivoting on one side like the single shock ones. Does that make any sense to anyone.

    Cheers
    Andrew :thumb
    #28
  9. Tanami

    Tanami Under The Weather

    Joined:
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    Oddometer:
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    Location:
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    Time to make that call to Rooney. He will be able to offer you qualified advise on the matters ocuppying your mind. There are plus' and minus' to both options (single and dual shock) and paul will be able to discuss these with you, as you say though...depends upon what you want the bike to do. My original breif to paul was that the bike should be able to carry (at the most) two people and light luggage (or one and heavy) at good speed across poorly surfaced unsealed roads and major tracks. An all road tourer. Consequently the frame and suspension where focused upon with durability in mind and the engine and drive with simplicity and efficiency. Keep thinking though...I did...for over five years before I made the plunge...by which time I was satisfied I knew (in detail) what I wanted and was not about to change my mind (given that a fiscal return on the investment would never be a part of the equation) even in the face of a new GS adventure!!. :deal

    cheers,

    stu
    #29
  10. a_k_nicholls

    a_k_nicholls Been here awhile

    Joined:
    Oct 8, 2003
    Oddometer:
    291
    Location:
    Near Canberra Australia
    Hey Stu,

    Your right, I have sent off an email to Paul & will see where we go from there.

    Thanks for your info too :thumb
    #30