My Barn Twins

Discussion in 'Airheads' started by fxray, Feb 26, 2015.

  1. aptbldr

    aptbldr easy rider

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    They seem fine so far. Not much variety of loads or miles on 'em.
    They probably weigh half what the KONIs did.
  2. fxray

    fxray Long timer

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    After what the Brits would call much faffing about, and unintentionally upsetting Noblehops a bit in some off-forum emails (though he showed amazing restraint), I finally made up my mind to do as he recommended in the first place. I have ordered a set of IKON 7610-1298 shocks, with adjustable damping and 3-position preload adjustment. These are the ones with the chrome body, black spring, and billet /6 replica cover, from IKON Shocks USA by Restocycle. They are like the one on the right in the picture that Noblehops posted earlier in post 838.

    I got sidetracked for a while looking at some IKON shocks listed on eBay that sort of look the same, but are going for a much cheaper price. I finally figured out that these are a different IKON part number (76-3005) that are made lighter and have fixed damping. They may be O.K., but I decided that if I'm going with new shocks I may as well make it worthwhile. I hope to run some miles on this bike.

    After doing some looking, I found that Noblehops lists those same 76-3005 fixed damping shocks on his website for actually a little cheaper than the ones on eBay. They would probably be a good alternative if somebody wanted to keep the cost down.

    Now I hope these shocks don't make the rest of the bike look too tatty by comparison. If those billet shrouds are too shiny, maybe I can still substitute the old original ones back on.

    Nils, if you see this, and since you will be changing out the standard springs anyway, I'd prefer the springs installed with the wider spaced coils at the bottom, so the progressive windings will be up underneath the cover. Some people prefer to show off the fact that they have the progressive springs -- I'd rather have them look more like the stock originals.
    Renner likes this.
  3. Jim K in PA

    Jim K in PA Long timer Supporter

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    How is the -1298 adjustable rebound damping adjusted? Is it just rebound, or rebound/compression adjusted simultaneously?
  4. fxray

    fxray Long timer

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    ^^^Jim, I assume (but don't know for sure) that it is rebound/compression adjusted simultaneously. There is a wheel in the top mount that you can spin with your finger to one of four distinctive positions, according to IKON. They say these settings "range from comfortable to sporty, to tune the bike to your own preference." I doubt if I would be a discerning enough rider to dial in rebound and compression separately and tell the difference, but maybe you could.

    You can look at this .pdf spec listing for a lot of info., including the shock they recommend for about any bike made. There is also a line drawing with dimensions in the final pages, if you scroll to the end. This document lists spring rates and sizes, among a ton of other information.
  5. Jim K in PA

    Jim K in PA Long timer Supporter

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    Thanks Ray - I could not make out the adjustment wheel in the photos.

    C & R damping should be adjusted for load, and for spring rate. Both of which are variable. I am getting spoiled by the (c)Ohlins I picked up for my rally bike. Very easily tailored to suit conditions.
    fxray likes this.
  6. Disston

    Disston ShadeTreeExpert

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    It has been my experience that buying the beat of the best pays for itself in ways I could not have foreseen.
  7. fxray

    fxray Long timer

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    Mufflers Backwards?

    So as to avoid mucking up the "Post your Airhead pics" thread, I'll put this in here. With a recent picture over there by Keithert, some comments were posted about his mufflers being on backwards, or reversed side to side. He and I are both from Illinois, a backwards state if there ever was one, so I got to wondering about the silencers on my own bike. I have trouble visualizing this, but it seems to jump off the screen at other people. Mine are aftermarket, which makes it harder for me to tell. I think I tried them on both sides when I was building the bike, but I really don't remember. What's your opinion -- are my mufflers backwards?

    Here it is parked with some airheads that have "normal" silencers:

    [​IMG]

    My bike is furthest to the left in the above picture. I was the only one not running Krauser bags that day, mainly because they looked funny with my silencers when I tried them on:

    [​IMG]

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    A normal R90/6 for comparison:

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    Some more pictures of my bike:

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    Sometimes they look right to me, other times, from a different angle ??? :hmmmmm

    [​IMG]

    I would take them off and see how they look switched, but I'm too lazy for that. I'd invite opinions. CafeDude and nmalozzi seem to have an eye for this in particular. What do you say?
  8. Gerg

    Gerg The Destroyer Supporter

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    They do seem a bit "splayed". The stock mufflers had a recess on the left side to clear the axle (IIRC). Mine are off the bike so I'm not sure.
    Park parallel to a known stock system, that's the only way to tell.
    If I ever get around to restoring mine I'll need new mufflers too. The entire system is beyond repair.
  9. James.A

    James.A ILL Airmarshal

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    Ray, your mufflers are aftermarket, so the rules do not apply. Gerg is correct about originals allowing for removal of the rear axle with the mufflers in place. You could try switching sides to see if that makes any difference, but at a glance, I don't think they would even be able to be fitted switched from side to side.
  10. fxray

    fxray Long timer

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    Thanks Gerg and James. I actually went out and stared at them just now and even got out the wrenches. Then I decided I was off on another tangent, so I stopped before I started messing with a running bike. Lord only knows there are enough other things to work on around here. Sometime I will pull them off just to find out. Meanwhile, I like them O.K. the way they are.
    dmftoy1 likes this.
  11. Pokie

    Pokie Just plain Pokie.

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    That's all that matters.
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  12. fxray

    fxray Long timer

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    My Ikon shocks came in this past Tuesday. I had originally asked for them to assemble the springs with the more tightly wound spring coils hidden up under the shroud, thinking that would make them look more like the original Boge shocks. That didn't happen for whatever reason, but it was no big deal. I have a fixture to disassemble / reassemble them.

    But . . . my fixture is now up to engineering change #2. It was first made to fit the Boge shocks and it worked well on them. Then I got into the old, orange, Koni shocks and the bore in the bottom plate had to be opened up about .070" bigger to fit the larger Koni preload adjuster rings. These Ikon shocks were bigger yet, so we opened the bore another .030" bigger. The preload adjustment rings are the same O.D., but the lugs on the outside of the Ikon body are a little thicker -- a bit heavier duty.

    [​IMG]

    Up top, both the bore and the counterbore had to be opened up to fit.

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    On the left is an original Boge shroud which fits the counterbore in the tool, and on the right is the new Ikon shock that's too big. Appearance wise, they are nearly identical. The new shroud is larger in diameter due to increased wall thickness. The old shroud had a .040" (1mm) thick wall, and the new ones are double that, as seen here:

    [​IMG]

    So, again, a bit heavier duty.

    The top clips on the Ikon shocks are also improved over the old Koni clips, being a bit larger and extending slightly further down into the spring to help keep the shroud centered. They also eliminated the need for one of the Koni pieces by changing the shape of the top clip:

    [​IMG]

    [​IMG]

    So, with the tool reworked, I flipped the spring on one shock and did a comparison. Here's one spring with the tight coils showing, and the other with the tight coils hidden up under the shroud. Functionally, there is no difference. It is only a matter of appearance:

    [​IMG]

    Originally, when I found that my old Koni shocks were not rebuildable, I had decided to buy just the new Ikon damper body and reuse the spring, shroud, and mounting hardware from my old shocks. I finally decided to avoid the chance that something wouldn't fit, and I bought the complete new Ikon shocks. So, while I was fooling around here, I checked to see if my original idea would have worked. Here is a picture of one Ikon damper body wearing the new spring and shroud, and the other wearing the old Boge spring, shroud, and the old preload adjustment ring -- cleaned up a bit. Can you tell which is which?

    [​IMG]

    Answer: the top one in the above picture is the shock assembly with the old parts. Notice that the spring on it is somewhat progressively wound. For comparison sake, I count 18 coils on the old spring, and 15 coils on the new one. The new spring is about .020" bigger on its inside diameter, and uses slightly heavier wire (.328" diameter, as compared to .300"). Actually, not a lot of difference, but I did not measure the spring rate of the old / new to compare.

    So . . . could you use the old parts on the new damper? Yes, for sure you could. I would recommend using the new Ikon top clip, and that would require opening up the hole in the top of the old shroud just slightly. I did mine with a small sanding drum in my Dremel Tool. I only had to make it .020" (.50 mm) bigger diameter, which was easy to do.

    While I'm confident the old springs, shrouds, and preload adjustment rings would have worked just fine with the new damper body (and saved some money in the process), I'm happy to have all the new stuff. In fact, I decided I liked the shocks better the way that Ikon shipped them in the first place. I ended up with the tight coils back at the bottom after all this fooling around.

    Oh well, I satisfied my burning curiosity in the process. :lol3 :lol3

    The old bike still has a long way to go, but the back wheel is no longer cribbed up on wood and a screw jack:

    [​IMG]

    If you look closely here, you can check out the historical accuracy of the new Ikon shock vs. the original Boge in the background.

    [​IMG]

    I think I already prefer the chrome damper body over the orange ones that have gone away.

    [​IMG]
  13. jagarra

    jagarra Adventurer

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    Ray,

    Do you have any issues accessing the upper adjusting wheel on left side, when I installed my new Ikons, the upper shock mount was covering a portion of the wheel.
  14. aptbldr

    aptbldr easy rider

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    New springs are 17% shorter length, a stronger/heavier reactive force.
  15. fxray

    fxray Long timer

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    jagarra, the LH side is a little more difficult, but I just went out to the bike and checked. I was able to adjust from "1" to "2" with my own fat finger on each shock. I did not need to resort to sticking a small screwdriver in there to move the dial, but I think you could do that without damage if you are careful. I'd rather not if I don't have to. Here are some pictures:

    Adjustment dial before the shock was installed:

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    RH upper shock mount:

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    LH upper shock mount:

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    RH adjustment dial:

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    LH adjustment dial:

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    aptbldr, if all the coils were spaced the same distance apart on both the old and new spring, the new 15 coil spring would be 17% shorter than the old 18 coil spring. In reality, the coils are spaced differently, so both the old and new springs have the same free length of 250 mm.
  16. aptbldr

    aptbldr easy rider

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    Fewer coils at the same length equal a shorter torsion bar.
    It's harder to bend a shorter lever, or torsion bar.
  17. fxray

    fxray Long timer

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    ^^^Well, these new springs are supposed to be a little heavier than standard, to accommodate my less than ideal body weight. Notice how I was able to describe my weight with the word "less" in the sentence? :lol3
    dcoop, bpeckm, Mouse and 2 others like this.
  18. fxray

    fxray Long timer

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    Back around the start of March, I got to wondering if I had accidentally installed my aftermarket silencers on the wrong sides on my '74 R90/6. I had put up some pictures and asked for opinions:
    It's too chilly to ride today and this silencer question was still bugging me, so I removed them just now and test fit them on the opposite sides. Now I know for sure that they were correct the way I had originally installed them. James.A, you were right.

    As they were, they didn't look right to me with the Krauser bags installed:

    [​IMG]

    [​IMG]

    But -- this would be the side view with the silencers switched from one side of the bike to the other:

    [​IMG]

    Some exhaust systems sort of look like this, and it might . . . maybe . . . be okay on here, but the Krauser bags wouldn't fit with the silencers upswept this way. Besides that, the brackets won't fit. Here's a look down from above. The body of the silencer is tight against the frame mount, and the holes are not even close to lining up:

    [​IMG]

    From below:

    [​IMG]

    . . . and perhaps the very best clue would be the giant "R" for Right and "L" for Left that are stamped on the silencer tabs (see above). :lol3

    Hey, when the silencers are installed, the R and L are hidden.

    Guess I better go clean the road salt off those silencers and put them back as they were.

    Oh well, it was too chilly to ride today, and doing this was better than shooting five holes in my freezer.
  19. aptbldr

    aptbldr easy rider

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    Too bad bags don't fit with 'em switched, that's a good look for an airhead.
  20. bpeckm

    bpeckm Grin! Supporter

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    "Oh well, it was too chilly to ride today, and doing this was better than shooting five holes in my freezer."

    Whoa! I"m impressed by the Illinois/parrothead connection:photog ....though you must've already used on of the rounds cuz it's actually six holes. We NewEnglander/sailor types know ZACKLY of what he sings... especially this year!



    As always, I do enjoy your posts and your sensayooma!

    :-)