R100 front suspension upgrades?

Discussion in 'Airheads' started by JonnyCash, Feb 6, 2011.

  1. JonnyCash

    JonnyCash turd polisher

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    I've got a frankenbike R100S engine and front end on a SWB /5. I'd like to improve the handling. I was reasonably happy with its handling until I got my tricked out RD350, and now I'm not so happy.What do you all recommend for upgrades? I'd think I'd like to lower the front end a little. I've had the bike for a long time, and it has always made a load clank when the front suspension tops out. Is this just the facts of life, or can I get rid of this? Seems like there would be some kind of bump stop to cushion this effect, but I haven't seen anything like that in there when I've had it apart. Thanks all.
    #1
  2. Jon-Lars

    Jon-Lars Jon-Lars

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    How large is your budget? :evil
    #2
  3. Wirespokes

    Wirespokes Beemerholics Anonymous

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    Which front end is on the bike? Are the calipers ATE or Brembo?

    It is possible to eliminate the clunk on top-out - they're either missing the rubber bumpers or you can install something called bottoming springs that actually are a better idea than the rubber which tends to deteriorate and clog the orifaces.

    If you've got the Brembos then it's possible to install Cartridge Emulators and greatly improve the ride. The ATE front end can be modded as-is since it's already a fairly sophisticated suspension.
    #3
  4. bikerfish

    bikerfish flyfishandride

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    an aftermarket triple clamp and a fork brace are nice to have also. keeps the noodle effect to a minimum.
    #4
  5. supershaft

    supershaft because I can

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    Why can't you put an emulator on an ATE fork? I have seen it done many times. I would not call it advanced as is.

    The right preload on the stock springs and the right oil can make a big diff on their own.
    #5
  6. JonnyCash

    JonnyCash turd polisher

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    I've got the ATE front end. Where does one get the bottoming springs? I find that clank to be quite irritating. It really stands out to me, as otherwise the bike makes me say "What a nice machine this is" every time I ride it.

    You say the ATE front end can be modded as-is. What do you recommend? Are there aftermarket springs that help? Different oil? I remember a long time ago I had a catalog from San Jose BMW/CCproducts, who had all kinds of hot-rod parts, but I can't seem to find anything about them, or anything else like them for old beemers.

    Thanks everybody for your responses, I appreciate it!
    #6
  7. mykill

    mykill odd

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    I suspect you will contact Matt Wiley (mwiley@racetech.com) at Racetech. I do not have personal on road experience with their stuff yet, but am in the midst of installing a gold valve and springs on my R75. I have yet to hear ANYTHING negative about their products or support, except for price, but we are all notoriously cheap. Matt has been super helpful in answering my questions. I will post the build at some point, but it is pretty straightforward so far.
    #7
  8. Wirespokes

    Wirespokes Beemerholics Anonymous

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    No reason you can't put emulators in the ATE forks, I'm just repeating what I've heard. It's also not as easy as the later ones and I've heard the emulators won't make that much of a difference. On top of that, a set of ATE forks in good condition and well se-up handle very well. I don't see any reason to fool with them.

    I'm not a fan of the stiffer springs that I often find in these things. They make the ride so stiff that every little bump transferrs to the bike. Guys attempt to remove the brake dive with stiffer springs and loose that wonderfully compliant front suspension. The better approach is to learn how to ride these things without jamming on the front brake. That's the way to eliminate the brake dive.

    The ATE front ends have a rubber bumper at the bottom to stop the clank on top-out. They should be available from the dealer, but the top-out springs, I don't know. They're just a spring as I recall, and perhaps a spring shop could duplicate them. I've got some around here somewhere, but have no idea what rate they would be, though I could give the dimensions.
    #8
  9. Hawk Medicine

    Hawk Medicine Coyote's Brother

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    I have to agree with you on this one.

    The ATE fork works very well if it's set up correctly. When I rebuilt mine, I used a set of medium stiffness progressive forks, the rubber bumpers and 7.5 weight oil. I also added a billet top clamp and a Telefix brace and now I have the best stock Airhead front end I've ridden so far. It's smooth and very compliant.

    I have heard that a good anti-dive spring is a pair of Chevy 350 valve springs. I'm going to install a pair and I'll let you know how they work but the tip cam from a pro Airhead wrench, so it might be a good one.
    #9
  10. Rob Farmer

    Rob Farmer Long timer

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    I went through a whole range of springs, oils and settings with my RS front end - spent a small fortune on it and had the forks apart more times than I care to remember. The best set up for me is standard springs and 5w belray oil. There are 3 small piston rings on each the dampers, these should be regarded as service items, I missed them initially and just could not get the front end to work properly.

    Motobins do a full service kit for the front end with everything you need. The Aeroshell 4 oil caused me lots of problems, personally I'll never go near the stuff again but I'm sure lots of people get on well with it.
    #10
  11. Big John Sny

    Big John Sny Been here awhile

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    It sounds like your forks are due for a rebuild if the rubber stops are gone. I was swapping over two the brembo front brakes so I never rebuilt mine. They were making the clunk sound pretty bad and I was thinking that it was handling pretty bad. I did leave my brembo front forks stock and simply rebuilt them. I also replaced the steering bearings while I was there and aligned the forks when I was done. The handling difference was amazing. I do not think the forks improved that much from 77 to 82, so I think most of my handling improvement was just having the front end work properly. You might try it before spending big bucks.
    #11
  12. bpeckm

    bpeckm Grin!

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    Looking for CC products, they still make and sell a very-reasonably priced triple-clamp which most would say is a HUGE improvement for the rubber-cow...

    Find it here.
    (the link is funky, for some reason, so just click on the blue and white "CC" along the upper left side, lots of yeehaw! parts for airheads....)

    [​IMG]

    Just know that the rubber stops that you "can't find" are probably there, but not in any recognizable form...

    [​IMG]


    :eek1 Yes, that WAS the rubber stops....

    :D

    EDit: oops, I just re-read and I now think that you have a R100 front end, not the /5 front end... oh well, those "stops" above are just as real....
    #12
  13. mykill

    mykill odd

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    Bottom line is that the forks are not working well and need to come apart to see why. If you ride under normal circumstances a properly set up ATE front end should be fine. If you are wringing its neck and taking it to the limit, I suspect you will want to seek more modern alternatives.
    The best news is that everything you would renew (except for springs)to get the stock front end back to spec will also be used if you decide to go with emulators down the road.
    #13
  14. Rapid Dog

    Rapid Dog bikes, booze, broads...

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    Best (affordable) setup back in the day for ATE was progressive springs/CC products top clamp, 7.5wt oil, and a fork brace, and bottoming springs can be made from the stock springs you'll have left over. Didn't get much better than that.

    I have a buddy that' selling a CC top clamp if your interested, complete with trimmed headlight ears. Lemme know I'll hook you up.

    I talked to Matt Wiley today about emulators. They make the emulators and matching springs for a complete kit. Best to call and find out which/what for the ATE's though. He said the website needs updating for the airheads. Very confusing otherwise.

    Not to confuse the issue, but for the '81 Brembo forks I was told that the slack in the damper rod at the bottom between the piston and the circlip needs to be nil and is taken up by shims available (MAXBMW)
    The internals on the ATE are quite different, especially the damper assembly.

    Best call Mr. Wiley and ask if you're going all out with the emulators.
    I'd think the "Best (affordable)' is the best place to start.
    #14