Africa Twin Spring Advice

Discussion in 'Japanese polycylindered adventure bikes' started by TeamExileRacing, Oct 10, 2019.

  1. TeamExileRacing

    TeamExileRacing I hunt dirt roads and places to eat

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    I' looking for some advice on my 16 AT fork and shock springs. I'
    Looking to upgrade to fix some problems I'm having.

    200lb rider in gear. Hard cases and top box usually on the bike. Infrequent 2up riding. 70% pavement, 25% fast gravel and 5% slow moderate difficult double track.

    Fronts springs were upgraded by last owner and they are way too stiff. I rebuilt them and know that they are linear springs but no idea of brand. Rebound is entirely too fast even with lowest preload and slowest rebound settings. I went through the entire fork and nothing was wrong with the internals. However due to the aftermarket springs I get clunking out of the suspension at full extension. Looking for something that is standard length but stiffer than stock. Thoughts?

    Rear spring is stock and too soft. Suspension feels good during road riding but way too soft with any amount of rough terrain. I also can't set proper sag even with full preload. Looking for something stiffer and longer. Been recommended hyperpro, thoughts?

    Thanks in advance for advice and relevant responses.
    #1
  2. Motociclo

    Motociclo Long timer

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    https://advrider.com/f/threads/crf1000l-spring-and-valving-data-base.1363798/

    Valving in forks and shock is very weak. Particularly rebound. Add higher rate springs, makes it worse.
    The clunk on extension in forks is back side of rebound assembly hitting inside the damper cartridge.
    Does this as simply because rebound is too fast.
    For best results respring and revalve forks and shock. Above link will get you something that will work pretty well.
    #2
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  3. TeamExileRacing

    TeamExileRacing I hunt dirt roads and places to eat

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    Thank you very much
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  4. TeamExileRacing

    TeamExileRacing I hunt dirt roads and places to eat

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    Man, that is a pretty incredible write up. You have definitely don' your research. I was always wondering why I only had 1.5 clicks on my fork dampening, you answered that.

    When you say that if you have longer fork springs you need to cut your spacer, what spacer are you talking about? I'm running stock valving with with said aftermarket springs with amsoil 10wt. I believe I measured fluid level without springs in, said heavir springs most like raised the fluid level resulting in even less dampening. Correct? I'm hoping I can get away with this setup without sinking more money into valving and new springs, is this possible? If so, what do I need to do? Tear down, measure springs to determine length and cut said spacer (pics please if possible), fix dampening adjuster, and reset oil level with forks compressed and springs in to 50mm? Does this sound about right?
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  5. Motociclo

    Motociclo Long timer

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    Spacer, sits on top of the spring. Most, not all after market springs are longer.
    Using my springs as example, they are 465mm long, stock are 435. 30mm difference.
    To maintain the stock installed preload of 10mm approx, 30mm needs to be trimmed off the spacer.
    If you don't trim the difference, you end up, using above example, 40mm of preload before you add any through adjuster. Way beyond too much.
    Remember, stock spring 435mm. If yours are longer, trim the difference from the spacer.
    The spacer at one end, has a plastic piece attached, this is at lower end. The top end, plastic piece comes off. Check link below, No. 3 in pic. Spacer is common to all AT models regardless of fork.

    https://www.mrcycles.com/oemparts/a/hon/5c2fcb9f87a8660b98794759/front-fork

    Measuring oil with springs in is okay if you get oil level around the 50mm from top.
    Aftermarket springs usually are thicker wire. More volume taken up. If you use the stock 95mm oil level with springs out, then use after market springs, it is likely that oil level height after this will be sub 50mm. I have seen a set of forks that had this. Seals leaked as fork was near hydraulic lock when bottomed out.
    You don't loose damping, you actually do help bottoming resistance have the oil level higher. The gap remaining is essentially an air spring, less air gap, higher pressure at full stroke. But there is a limit.

    I use the 50mm spring in method as it covers any spring and gives you stock air gap. Want a bit better bottoming, raise oil level to 45mm springs in. I wouldn't go higher than this.

    Pull forks apart, check you spring length, trim spacers required. Put spring in, have fork collapsed, set oil at 50mm from top,(with springs in), then lastly set your rebound adjust range. You will be golden.
    10wt oil is fine.
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  6. TeamExileRacing

    TeamExileRacing I hunt dirt roads and places to eat

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    Your the man! I will rear them down and see where I'm at. I' say the springs are longer and tones were never cut. This was an absolute hoss to get compressed to reveal jam nut under the cap, that and I have absolutey no sag.

    As for rear springs you say your running k-tech. How would I go about determining the spring rate that I need between their available options of:
    • 100.0
    • 105.0
    • 110.0
    • 120.0
    Again, too much sag on stock spring with my weight set at maximum preload. Shock is entirely too soft. Also you said you run 2.5wt in rear shock? Would 5 or 10wt be too heavy?
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  7. Motociclo

    Motociclo Long timer

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    Ktech springs,
    100nm equals, 10.2kg spring.
    105 equals, 10.7
    110 equals, 11.2
    120 equals, 12.2

    I believe stock shock oil is 5wt.
    If you got that for a revalve, that would be okay. But all the shock revalve stacks i quoted are using 2.5. I can offer stacks for what ever oil one desires.
    Maxima make a 3wt which is close and would work.
    In saying that, there are 5wt labelled oils that are close to 2.5wt, this has to do with a measurement called centistoke, CSt. Important, always choose a shock oil with a high viscosity index, 300 plus.
    I wouldn't consider 10wt in shock. It would get to hot in rough terrain and fade. Lower weight oil in hard terrain with stiffer valving is better. Better all round.

    Here is a oil list that you could look at to choose a shock oil. I use Motul VI400, ( i think it is under Motul 2.5wt), find it, check the CSt number and compare to others. Will make sense as you read through.

    http://www.peterverdone.com/wiki/index.php?title=Suspension_Fluid
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  8. TeamExileRacing

    TeamExileRacing I hunt dirt roads and places to eat

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    You the man! Thanks a bunch, you'e answered all the questions I had.
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  9. TeamExileRacing

    TeamExileRacing I hunt dirt roads and places to eat

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    How did you decide on the 105 spring rate? Whats your weight and riding habits? Best I can figure from some rough calculations, this is the spring I need as well. Where would be the best place to order these in the US? Everything I'm finding comes directly from the UK
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  10. TeamExileRacing

    TeamExileRacing I hunt dirt roads and places to eat

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    Also, do you know the oem length of the spacer. I didn't see it in your write up. Just want to confirm my spacer has not been cut yet.
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  11. Motociclo

    Motociclo Long timer

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    Calculated what spring i needed.
    I have a couple of calc methods.
    Weighing bike and rider and calculating gets it close.
    My weight, geared up, 117kg plus about 20 kg of panniers and gear in them.
    I don't pillion. Riding, a mix. Not a lot of single trail. But will do fire trails.

    Length of spacer.
    With plastic end bits included, 418mm.
    Just the metal, no plastic, 400mm.

    I got my Ktech spring through rugged roads.
    If you pillion a bit or carry a bit if weight, the 105 would be good. Based on just your weight and minimal luggage, the 100 maybe better.
    Sag, i ran 65mm for a long time . Now, i sit at 73mm. This is plenty good enough.
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  12. TeamExileRacing

    TeamExileRacing I hunt dirt roads and places to eat

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    You the man! Thanks mate.
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  13. gve.mcmlxxiv

    gve.mcmlxxiv 2016 Africa Twin DCT No.272

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    I put stronger springs in the front before I did the shock spring. That was a mistake. Need to do all three springs at same time. Made the bike unstable feeling at high speed which didn’t go away until I put a stronger shock spring in. I was able to get the sag I wanted up front but not in the back, like you. Found out from experience, Geometry from sag is important. I’m working on front rebound and compression next because it’s too harsh. Lots of knowledge here.
    #13
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