72' R75/5 Cafe Build Thread - Leadnuts

Discussion in 'Airheads' started by Leadnuts, Apr 24, 2012.

  1. supershaft

    supershaft because I can

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    Hopefully that's how it works since most aren't perfectly centered on the swing arm pivot. I pointed out the same issue with a setup bmweuro was making. He came up with a pretty cool solution but his was with cable. I would rather use a rod too but sometimes I wonder because I think it is easier with cable.

    I suspect Leadnut's setup will have less of a varying petal than the one in the photo. The one in the photo is probably a whole inch above the pivot whereas Leadnuts is further in front of the pivot but more central to the radius of the swing arm. I hope that makes sense? Pretty much the same angle BMW took. I would use a rod and some heim joints on the linkage Leadnut.

    I wouldn't mind making my own hangers but with round tubing if for nothing else but looks. I want to make my controls out of real thin wall round tubing too just like BMW did with their old GP bikes. Same with the pegs.
    #41
  2. Jon-Lars

    Jon-Lars Jon-Lars

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    [​IMG]
    #42
  3. Leadnuts

    Leadnuts do-over...

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    Jon-Lars... that looks nice! Mind showing the rest of that bike? Man, that would have been really helpful 11 hours ago. I feel like I just reinvented the wheel, which I know had already been around for a very long time.



    Do I need to go with stainless linkage joints?



    I think I have a paint scheme I like.

    Toast tank and seat cowl will be a white,

    Frame, headlight bucket, clip on bar sections and maybe wheels will be black. Don't know about wheels yet, as I can't decide what to do with the lower fork sections)

    Seat will be upholstered black with ribs.
    #43
  4. Jon-Lars

    Jon-Lars Jon-Lars

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    Here's a photo album:

    http://tinyurl.com/R80GS-album

    Check your lever ratios on the linkage. You can get sufficient pressure on the brake shoes if you keep close to the stock ratio - which is 23mm/5.3mm, or 4.34/1.

    (Multiple lever ratios are multiplied to get the overall ratio)
    #44
  5. Leadnuts

    Leadnuts do-over...

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    Is that a ratio for travel, or arm length?



    Also... thats a pretty beautiful bike, painfully beautiful.
    #45
  6. Jon-Lars

    Jon-Lars Jon-Lars

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    Arm length, and thanks.

    I'm really enjoying it.

    It's build was 2002 through 2005.
    #46
  7. supershaft

    supershaft because I can

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    I think that is about the best way to do the mechanics of it. I would love that setup if the bracket, controls and foot pegs were welded up out of super thin wall steel tubing in memory of BMW's last GP efforts. I would try running the brake lever's lever on the inside of the foot peg bracket as well for a cleaner look and at the same time keeping the foot pegs themselves more narrow. The narrowest they can be is still pretty wide IMO. For instance, I have always run my stock passenger pegs on those two inch (?) long BMW foot peg offset brackets. I set the offset forward and a bit higher than the original passenger foot peg position and use those foot pegs a lot while I am riding. I regularly drag those foot pegs! The rubber on their ends is ground off. Even with rear sets you still have to watch your cornering clearance! Don't try that at home! I shorten my forward foot pegs about a half inch in order to keep them out of the pavement otherwise I don't think I could ever get into my passenger pegs. I also torque down my engine while it is jacked up. You can get the engine about 1/8th inch higher doing that and it does make a difference with the lean angle. Like I always advise, the little things add up!
    #47
  8. Voltaire

    Voltaire Bored Of The Rings

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    I've got a set of those Tarrozzi's on my bike, I drilled out the hole in front of the pillion peg ( as it was there).
    My engine is raised and I have touched the heads down a couple of times but have yet to ground the rearsets.
    I found the std brake pivot too short to work and extended it about 30 mm to improve the leverage....still needs work but then I only use the rear brake to preload the front in the wet.
    Nice bike build.:D
    [​IMG]
    #48
  9. sparkymoto

    sparkymoto Learning a lot here

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    Fun project! Just caught up. I did the same thing with the set screw on the old cut down brake "pivot-er" :)
    I need to improve the leverage on my brake side...cool to see more discussion and set-up refs here.
    #49
  10. tall2

    tall2 n00b

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    I like your cafe. I have a R90S with a sidecar. The bikes rear swing arm was converted to a single shock as yours is. I need a new shock and wanted to ask what you used, what spring rate did you get, and how long is it?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>
    Thanks, Frank.<o:p></o:p>
    <o:p> </o:p>
    #50
  11. Leadnuts

    Leadnuts do-over...

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    Its been a while since I've had any time to do any work on the bike... Time to get back at it..



    I have been looking desperately for some alternatives for the fork tube top bolts... I have racked my brain and seen the end of the internet and have had little luck finding anything... Which leads me to believe that I am searching incorrectly. The bike has 36mm fork stanchions, I cannot find a thing? I see some of your guys and gals bikes with some non stock bolts, could any of you chime in to give me an idea as to where you found them, or if there is some other bike out there that has the same size. Thanks.

    Work started on cutting the waffle head part off the kick start lever to use as the front peg of my brake-side rearset to give a wider toe surface to bare down on. As well as looking a bit more aggressively badas- I'll post a pic when I get it a bit further in the make.

    Next decision is weather i want to weld the subframe to the main frame instead of using the bolts.. can't think of down side.

    Made a stainless linkage rod for the gear side, waiting on a right angle linkage part, and i will post a pic.
    #51
  12. Leadnuts

    Leadnuts do-over...

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    here is what i've decided to do with the top bolts...

    modify the original to what I wanted..
    the bottom one I have mounted in a drill press and held a die-grinder to take down the top shoulder so it will sink down into the tube further. Cut a short length of round stock to weld into the top opening.

    [​IMG]

    Then ground it down..

    [​IMG]

    and what it will look like.. I will probably be painting or p-coating them black.

    [​IMG]



    And this is what I'm planning to do with the brake pedal. The waffle part is cut from the kick start pedal/level.

    [​IMG]
    #52
  13. Leadnuts

    Leadnuts do-over...

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    Got a few hours today in.. Made a new headlight bracket as the previous one was a different diameter of material than the mirror and it bugged me so do-over... added a little and seem to like it more. Also made the linkage on the gear side, as well as finished the (what i think is cool looking) brake pedal mod.

    Here is the new headlamp bracket and process shot..
    [​IMG]

    [​IMG]

    I'm going to mod it to shorten the projection forward and lower it a tad.. its just tacked together at the moment.

    Brake mod adds a lot of foot support on the rearset.. and looks badas-s

    [​IMG]


    and the linkage.. then ran out of time.

    [​IMG]


    Ah, almost forgot.. figured out a way to use the existing brake light switch.. Mounted it vertical, and made a little arm that bolts on. little hard to see i the pic.
    [​IMG]

    have a nice weekend
    #53
  14. benthic

    benthic glutton 4 punishment

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    i love your build. very nice work!
    #54
  15. JonnyCash

    JonnyCash turd polisher

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    Hey, I like your headlight bracket there. It's much like something I've been thinking up for my T3. Also, I see that you've used a /2 steering damper knob on there. I've always wanted to get one for my /5. Did you have to change the length of the stud in it, or do anything else, or did it just work out? Nice bike there, sir!
    #55
  16. Leadnuts

    Leadnuts do-over...

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    Thanks guys,

    The knob isn't attached to anything yet but it look like it would work out.. I haven't attached it because it feels like it sticks up so ridiculously high. I might shorten the stalk a bit or just make something entirely different... Seriously it feels like it might hit my jaw if I hit a bump. Funny thing is, it isn't all that much taller than the original, but for some reason it seems waaay taller. The shape is super nice though.. so I don't know.... decisions, decisions...


    By the way, if you end up doing a similar bracket there are some roll pins in the lower brace that seem to work brilliantly as a place to fasten when you tap them out.
    #56
  17. Leadnuts

    Leadnuts do-over...

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    im looking at my exhaust and would like to do something different... But not sure what sort of options are possible. I have a 2 into 1 system now and would love to shorten the actual muffler part. Or get a shorter one. Is this possible or does some sort of calculation need to happen. I see "slip on mufflers" and was thinking that's what they are for but I'm not quite sure.. Anyone? was also has anyone bought one of the kits with a bunch of bends and strait tube and made an exhaust themselves?
    #57
  18. Jon-Lars

    Jon-Lars Jon-Lars

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    Ahem...

    [​IMG]



    [​IMG]



    Yes, you need to calculate the header length and the single length to the muffler, according to your engine specs.

    Well worth it.
    #58
  19. backdrifter

    backdrifter Wannabe rider

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    Your bike looks awesome, leadnuts! Lots of tasteful, well thought out, and skillfully executed mods! I'm enjoying this one - carry on!
    #59
  20. Leadnuts

    Leadnuts do-over...

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    Jon-Lars..... Your killing me with your pics. That is such a lovely bike. I will look into that, of course I was hoping to just keep my headed and stick a different silencer on the end.... Yeah guess I'm going the long route.....again. Are there tables floating around with info on this?

    Thanks backdrifter..
    #60