New Airhead on the Block + Noob Questions

Discussion in 'Airheads' started by gfx, Nov 27, 2011.

  1. gfx

    gfx gfx

    Joined:
    Nov 23, 2011
    Oddometer:
    41
    Location:
    San Francisco
    Hey All,

    Long time lurker but new to the forums. I was a K-Bike rider for little while but went airhead when my precious K75S was totaled by an old lady in a minivan. Le sigh.

    Luckily, I found a 1977 R100/7 from the original owner in Napa, CA with only 38K miles on it. For the most part, the bike was incredibly well maintained and it's been a joy owning it.

    Here it is after I removed the atrocious luftmeister fairing and replaced the USA bars with the S (euro) bars. (more pics HERE)

    [​IMG]

    I have a few noob questions for the airheads among us. I've searched the forums and the googles extensively but hopefully you wouldn't mind answering a specialized question or 2.

    I'm definitely not a mechanical genius but I'm a pretty quick learner.

    1) Tires Available (serious tire noob)

    All the normally recommended tires (Battleaxes, Spitfires, Conti Go's, etc etc) seem to all be only be available in metric sizes vs imperial. The Metzlers are way overpriced and paying $250-300 for a set of tires seems pretty outrageous.

    I'm in the USA, and we seem to be shit outta luck in terms of getting some true 3.25/4.00 tires out here. Most of the well-written guides suggest 90/90 and 110/90, but no one really makes a tire in 90/90 except the Spitfire S-11's.

    Anyone ever ordered a pair outside the country and get 'em shipped? I'd rather pay to have some true 3.25/4.00's imported than use an untrue tire size.

    2) ATE single brake Rebuild / Adding a second disk.

    My bike has the single ATE caliper disc brake. Although I originally was checking out a possible brembo 4-spot caliper conversion (by infamous, snowbum: http://bmwmotorcycletech.info/brakes.htm), it seems that this conversion is only possible when going from a 2-spot brembo to a 4-spot, and not from the ATE caliper. I'd love to be wrong here, as adding a 2nd disc is certainly a lot more expensive. If anyone has done this conversion I'd love to hear about it.

    Short of replacing the entire forks and/or wheel, I assume that leaves me with just possibly doing a rebuild on my ATE?

    Again, apologies for the noobness, but in order to convert to a dual disc would I only need a fork slider from a dual disc on the right side?

    3) Ikon vs. Progressive shocks

    I realize this is probably almost purely opinion, but if anyone can comment on Progressive vs. Ikon shock experience, that'd be great. I'm a big rider, 6'3", 250lbs, and I ride pretty aggressively in downtown San Francisco and the hectic freeways. Pretty much the worst of both worlds :)

    Any feedback appreciated.

    PS: If anyone is interested, I'm about to finish up a full LED conversion (turn signals, brake light, full cluster) on my bike. Let me know if a guide would be desired.
    #1
  2. disston

    disston ShadeTreeExpert

    Joined:
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    Oddometer:
    12,305
    Location:
    Silver Spring, Md
    Conversion to Brembo requires changing the forks. And I think some of those if not all don't work with the spoke wheels. It comes down to, if you want to keep the spoke wheels you have to keep the ATE brakes. There are some rare exceptions. I've not done a lot of investigation of this conversion because I'm not interested in doing it but it comes up a lot and there are hang-ups.

    Adding a second ATE caliper requires finding a right side fork lower that will hold the caliper. The rest is easy, another disk, maybe a different master cylinder, hoses. But the right side sliders are hard to find because everybody wants to add a second caliper. A used fork slider might cost $250 or more. If you can find one for sale.

    A semi-floating caliper will help. EBC rotors for that bike are available. Have seen it said that this is more improvement than a second caliper. Don't know myself but I'll use one someday when I have the bucks. There are some for sale right now for $204 on Ebay. I think they can be sourced for less than that but they aren't cheap. Still it's the cheapest easiest way to improve your brakes.

    You mention rebuilding? Are there leaks now? Where? Brake fluid is supposed to be changed once a year.

    Charlie
    #2
  3. WU7X

    WU7X The Old Fart

    Joined:
    Aug 21, 2007
    Oddometer:
    2,315
    Location:
    Spoke Can, WA
    Zack,

    What an incredible find! Looks like the bike found the perfect new owner. I sincerely hope that the pair of you have years of fun together.

    I, for one, would really like to hear about the LED conversion. I have a '82 R100RT that has been converted into a hack. I'm torn between keeping the electrical system stock, and going all out and replacing the lights with a system similar to yours. I also want/need to add some kind of lighting on the front of the Squire sidecar. So please consider doing a writeup on your LED conversion. Pics would also be greatly appreciated.

    Dale WU7X
    the Old Fart
    #3
  4. d mc gee

    d mc gee Been here awhile

    Joined:
    Nov 26, 2006
    Oddometer:
    805
    Location:
    Upper Sandusky, OH
    +1 on the LED conversion.
    #4
  5. Mallard

    Mallard insert joke here

    Joined:
    Aug 31, 2010
    Oddometer:
    82
    Location:
    Brisbane, Australia
    Hi gfx,

    You're in just the right country to get suitable tires at a good price.

    AVON Roadrider tires are available in 3.25-19 and 4.00-18 from Rocky Mountain ATV for $96 and $115. Roadriders are a a good tire IMHO. I it's cheaper for me to get them posted to Australia, than to buy them here.
    #5
  6. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,305
    Location:
    Silver Spring, Md
    BTW pretty bike. Welcome

    Charlie
    #6
  7. Bill Harris

    Bill Harris Confirmed Curmudgeon

    Joined:
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    Oddometer:
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    Location:
    backwoods Alabama
    Ditto on the Avon Roadriders. Good handling, expecially in the wet and have a lack of sensitivity to rain grooves, and decent wear (I typically get 19K on fronts and 10K on rears), in inch sizes and moderately-priced. Bridgestones (S-11 I think) are less expensive and reportedly better-wearing but I don't have first hand info on how they handle. I've thought of trying them next time I replace both tires at the same time on my bike, but I've had such good results with the Avons.

    And congrats for coming back from The Dark Side.

    (or the Brick Road, whatever)... :D
    #7
  8. coastranger

    coastranger Been here awhile

    Joined:
    Jun 16, 2009
    Oddometer:
    429
    Location:
    coast range oregon
    the slider is getting harder to find, due to age and like mentioned , lots of people doing the conversion, but keep watching the forums, even the BMWMOA. Fleabay of course.
    Yes a floating rotor and a correctly adjusted brake system makes a big improvement on the single disc bikes

    I converted my 78 R80 to dual disc adn floating rotors, giant improvement. Sold that bike.

    Now riding a factory dual disc with floats and sticky pads, very happy (85 RT)
    #8
  9. Wirespokes

    Wirespokes Beemerholics Anonymous

    Joined:
    Jul 26, 2002
    Oddometer:
    8,696
    Location:
    Jackson's Bottom Oregon
    Welcome to the forum!

    Nice bike!!

    I've used the Bridgestones for a long time and they're great. Don't worry about the metric thing - no need getting anal about inch sized tires - metrics fit just fine. :evil Your bike will take a 100x90 19 front, and the 110x90 18 rear. The 120 rear is difficult to mount and install, plus doesn't handle as well - sluggish handling.

    I've used both - the S11 and Battlaxe and love both, but the S11 is cheaper, the battlaxe stickier.

    One of these days I'll have to try the Avons, heard lots of good about them.

    With the right pads, new brake fluid, no grunge in the system and everything working properly, the single disc can stop very well. Watch for the parts for a second disc - they show up - you'll need the second disc, caliper and the slider. An easy solution for the master cylinder is to have a custom line made up that splits near the fender to supply both calipers.

    Progressives are supposedly at the bottom of the quality list for rear shocks. Better off staying with Ikons, YSS, Wilbers, White Power, etc.
    #9
  10. coastranger

    coastranger Been here awhile

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    Location:
    coast range oregon
    one more idea
    go to a handle bar mounted master when doing the switch
    if not go with a 14 mm. does not sound like much, but the bigger the bore, the less pressure at the handle to push the same fluid
    also its strange , but if you put on a 120 on the rear it has to "crunch and roll" to fit in the rim and the result is you end up with less tread pattern hitting squarely on the road then a 110. well at least thats been my experience ( at least on the older rims)
    #10
  11. gfx

    gfx gfx

    Joined:
    Nov 23, 2011
    Oddometer:
    41
    Location:
    San Francisco
    Thanks everyone for the valuable input. I feel like I'm slowly molding my long and short term plans.

    It seems like the spoke wheels are really a "gotcha" with my bike. If I wanted to do anything with the calipers or put some different forks on the bike, I'd definitely have to spend $$$ on a new wheel(s) as well. Perhaps an airbrick (k-bike front end) will be a separate project; The San Francisco area has a ton of cheap airheads for sale all the time that are begging to be projects. This R100/7 is too pure :D

    I decided to remain anal about the imperial tire sizes and purchased a set of Avon RoadRiders in 3.25/4.00 sizes.

    I just replaced every single fluid in the bike about 2 weeks ago, so the braking power definitely has no relation to the fluid or brake line. I haven't given the caliper a proper inspection, so sometime soon I'll take it apart and check for anything I need to replace. I replaced rotors on my previous Kbike with EBC's and that's the route I'll be going when the time comes; real quality stuff.

    To be honest, I think changing the master cylinder size is a bit of fluff and I likely wouldn't have an issue using the existing under-the-tank MC with an additional disc. A little bit of softer feel on the brake lever with the dual discs wouldn't bother me enough to warrant a $200-500 MC.

    This is probably a silly question, but I'm guessing you can't just stick a left-side fork slider on the right side turned around? That would just be too easy, right?

    Again, thank you all for your input. I had to put the LED conversion down for a few weeks until after the new year, but after that I'll finish it up and write a guide for doing it.
    #11
  12. SprintSix

    SprintSix Been here awhile

    Joined:
    Dec 24, 2009
    Oddometer:
    152
    Location:
    Ohio
    Spoke wheels. Only a gotcha if you dont upgrade your brakes with a smaller master and stainless lines. An extra caliper helps but the line and master, along with proper bleeding will do wonders. Its certainly not "fluff", and far cheaper than a complete front end swap.

    Swapping the left to right sliders does not work. Adding a caliper is a very popular mod and it reflects in the rarity and price of the conversion. i.e. They get snatched up as soon as they hit the internet.

    You'll save a lot of time and heartache, not to mention money if you just leave it alone and ride it.
    #12
  13. disston

    disston ShadeTreeExpert

    Joined:
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    Oddometer:
    12,305
    Location:
    Silver Spring, Md
    It is possible to use a left slider on the right side but it needs modification. It will not look exactly factory made with out a lot more work. The axle hole on the left side is smaller so that can be bored. It is not a job for a hand held portable drill. The finished hole must be straight and the correct size. The mounting hole, place for the caliper cam, is in the right place but the pads the caliper are ridding in are not symmetrical. The pad area needs to be cut and have a piece welded to one side. The area has to be finished flat.

    That's it in a nut shell. Not a novice project IMHO. It has been done. It's really the sort of project that somebody might do for themselves but not be willing to do for somebody else. No idea what the cost would be if you could find somebody to make one. I think pretty high. With the right side caliper sliders getting more and more rarer all the time this modification might became more popular. There has been talk from some of the machinist qualified to try and make some of these for sale. I haven't heard of any being ready yet but you may see something like this in the near future.

    Changing to the handle bar MC and using a smaller bore MC are both worth while improvements. It is a function of hydraulics which is a part of mechanics that we are dealing with. If you don't see what exactly we are talking about we will have to keep this thread alive for several more days till you get the point.

    As far as steel braided brake lines go, I'm not a fan of those. I'll save my explanation for now unless you really want to know. If you want to use them then please go right ahead. I have one on my R90/6 right now but it came on the bike. I'm going to be eliminating it when I convert to dual ATE's in the near future. I have the parts BTW. I bought everything needed over ten years ago.

    Charlie
    #13
  14. gfx

    gfx gfx

    Joined:
    Nov 23, 2011
    Oddometer:
    41
    Location:
    San Francisco
    I'm certainly not ambitious enough to try a stunt like this. I'm fairly confident the caliper hasn't been serviced in about 10 years, besides the new brake fluid I put in and the fact the brake cable looks and feels brand new. I'm definitely going to check into cleaning and possibly rebuilding the ATE caliper. It sounds like some TLC will go a long way.

    It appears the MC size is a little more important than I had realized. I'll surely take this into account and read up on airheads.org and Snowbum's site.

    My ambitiousness is a mixture of over-zealousness and the consideration that I live in downtown San Francisco and often have to come to very quick stops. Forgive my hard-on for upgrades :rofl
    #14
  15. squiffynimrod

    squiffynimrod maximum shrinkage

    Joined:
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    Flatskatchewan
    LED's. I'm specifically interested in which instrument bulbs you use. Keep us posted.

    Thanks.
    #15
  16. exhaust_nut

    exhaust_nut Been here awhile

    Joined:
    Sep 4, 2005
    Oddometer:
    195
    Location:
    San Diego, CA
    "PS: If anyone is interested, I'm about to finish up a full LED conversion (turn signals, brake light, full cluster) on my bike. Let me know if a guide would be desired. "

    Beware if you convert to an LED for the GEN light in your gage cluster you may have a problem with the charging system. The alternator exciter circuit passes battery voltage through the alternator (GEN) bulb and the rotor to ground, you need an LED with the proper draw to get the battery to charge.

    Or you can add on of these- CLICKY<!-- / message --><!-- sig -->
    #16
  17. disston

    disston ShadeTreeExpert

    Joined:
    Mar 22, 2011
    Oddometer:
    12,305
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    Silver Spring, Md
    Keep looking for the rare slider. You might get lucky.

    It is an improvement to properly align the caliper and the change to an EBC or other aftermarket disk is a large improvement.

    The steel braided brake lines, even if I don't like them, are more rigid. Riders report this is an improvement in braking.

    Even a fresh cable from the handle bar to the under tank master cylinder can be an improvement. The old cables get stretchy as they age. This is the theory. I changed mine years ago and did feel good about doing that. This cable rarely goes bad so it rarely gets changed for any other reason. Riders don't think it needs changing if it works.

    I lived on the streets of downtown San Francisco after I got out of the Army in 1969. It was really a different world in those days.

    Charlie
    #17
  18. Arkwright

    Arkwright Grumpy ole Git

    Joined:
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    Location:
    Lincolnshire, Engerland
    You should be able to get the correct slider and the other bits second hand from either Motobins or Motorworks in the UK. Personally I would do the conversion to Twin discs with Brembo brakes and handlebar mounted master cylinder but I have a lathe to make the necessary spacers and bushes (I'm doing it to my Caff Racer) similar to this.

    Attached Files:

    #18
  19. gfx

    gfx gfx

    Joined:
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    Oddometer:
    41
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    San Francisco
    Are those 2-spot brembos on the same forks that use the ATE calipers? Did you do a conversion, or do you have a later model airhead with a different brake configuration?

    I'm definitely interested in the dual disc, but for now I think a caliper rebuild will go a long way. The DPO's documentation of the bike stopped in 2001, and a caliper rebuild was on his to-do list. The front wheel seems to be squeaky at times and this is definitely going to be investigated; I figure I'll take it one step at a time instead of diving into a pricy and laborious job. Perhaps a rebuild and an EBC disc/pad will be satisfactory.

    disston: I'm not one for SS brake lines either.

    exhaust_nut: This is actually more elegant than what I was going to do, so thanks for that. As I'm sure you know, there is no LED that will fit and draw anywhere near the normal current. My bike doesn't have a volt meter, so it's a bit of a risk indeed. I'll note the risk in the guide I conjure up.
    #19
  20. Arkwright

    Arkwright Grumpy ole Git

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    Those are twin pot Brembos on 'K' Sport forks fitted to a '77 Caff Racer.

    Attached Files:

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    #20