LC4 Suspension: To revalve, or not to revalve?

Discussion in 'Thumpers' started by Stobie, Mar 15, 2005.

  1. Stobie

    Stobie Mr. Motivated

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    I'm torn. :scratch

    There's no doubt that the springs on my 640 Adv are too soft for my 215 or so pounds. I'm sure that changing to stiffer springs and fresh oil would be significant improvement, and there is so much damping adjustment available that revalving simply because the springs are stiffer shouldn't be necessary, especially if I go with heavier than stock oil.

    I've never had the suspension on a dirt or dual-sport bike revalved, so I haven't experienced the difference. Some people say it can make the bike more plush and more bottoming-resistant, but I wonder if it's worth the expense and down time for a dualsport bike that's not going to be raced.

    Right now, the bike handles bigger hits better than smaller bumps, at least until it bottoms. Most of my riding is dirt roads that can be fast and/or bumpy, or rough, rocky trails. I haven't gotten big air with it, but I imagine it wouldn't be hard to bottom out, since I can practically bottom the front end with the front brake on pavement.

    OK, now I'm rambling. Any of you guys have experience with revalved suspension on one of these bikes, versus just changing the springs? Is the extra $300-$400 for the revalving worth it? :ear
    #1
  2. markjenn

    markjenn Long timer

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    I had the forks revalved on my 300EXC which, with stiffer springs, are the same forks as on my LC4. The suspension was improved, but only marginally. I think when you get the spring rates correct, sag set correctly, clickers dialed in, and clean/correct-vis/proper-height fork oil, you're 95% of the way there, especially on a non-MX bike like the LC4.

    - Mark
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  3. Rocamojo

    Rocamojo Toasted on both sides

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    FWIW, I have resprung my Adventure and it still bottoms chronically in the rear off-road. I had the forks working pretty good and they probably could be further improved with additional testing and adjusting. However, the shock is maxed out on compression and bottoms on everything. The bike has under 2500 miles on it. So since it probably needs a suspension service I am going to have to do the revalve. I'm a bit lighter at 195.

    That said, springs may be all you need. It really depends how you are going to ride it. I would suggest respringing and if thats not enough, have it revalved.

    Just my 2 cents worth.
    #3
  4. Hipster

    Hipster Long timer

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    I replaced just the fork and shock springs, and it made a big improvement for off road riding. However, the rear shock is still a little soft for off road use so, next time it needs to be rebuilt I'm also going to have it revalved.
    #4
  5. Stobie

    Stobie Mr. Motivated

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    It sounds like the prudent course of action would be to go stepwise; respring first, then revalve as necessary. Maybe that should have been obvious.

    Thanks for the insight, fellers. :beer
    #5
  6. Flanny

    Flanny Flanny-it-up!

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    Revalving the fork and rear shock were the single best improvements made on my 640 Adventure.

    Everthing about the bike felt better - cornering, bottoming, whoops, even riding straight down the highways.

    IMHO respringing and revalving forks should be the first thing done to any bike - even before pipes and stuff. It makes that much of an improvement.

    you would probably be a much smoother and faster rider with good suspension rather than any engine work you could do.

    :thumb
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  7. 2whlrcr

    2whlrcr gooligan

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    So what fork spring rate did you guys go to? Just curious, since I just got new .46's, but have not put them in yet. I weigh 200 in riding gear.
    #7
  8. meat popsicle

    meat popsicle Ignostic

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    i dunno if there is a suspension whiz around here like the engine gurus - the suspension stuff is part voodoo - might wanna consult a good suspension speciality shop.
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  9. Flanny

    Flanny Flanny-it-up!

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    I'm pretty sure mine were .48s, pregressively wound by Eiback. I weight 170 and add about another 10-15lbs with gear.
    #9
  10. Rocamojo

    Rocamojo Toasted on both sides

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    I put in .47s in the forks and a 7.6 in the rear. If I had to do it over, I would go .50 in the forks and at least 8 in the rear. But I'm going to let a suspension shop tell me what I need when I get things revalved. I should have done so in the first place. Flanny had the right idea IMO.
    #10
  11. Hipster

    Hipster Long timer

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    I weight 200lbs and went with WP 48 fork springs and a WP 8.0 shock spring per Factory Connection's advice (640 enduro model, w/18L tank). They were very helpfull and they stock WP springs.

    Tom
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  12. Stobie

    Stobie Mr. Motivated

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    OK, so it sounds like you heavier guys who just resprung wish you had revalved, too, at least the rear shock. Makes sense, since the factory setting on the compression damping for the rear is one click out from full stiff.

    Now, I just need to decide who's gonna do the work.

    I've talked to John Curea at MX-Tech East Coast Suspension, and feel really good about his operation. He gets lots of :thumb from the KTMtalk and ThumperTalk guys, too.

    But, while talking to Gary Emig about other stuff, I learned that Emig Racing does revalving work also. Apparently his son Brian does the suspension work, but they don't list anything about it on the website. I feel pretty good about anything Gary does, and since he rides an LC4-E himself, they've probably got the settings for those suspension components pretty well dialed in.

    The fact that they are a little cheaper ($150 per end v. $175) doesn't hurt. Also, he did all the setups on Jeff's bikes before Jeff got a factory ride, and Jeff was pretty successful (but he's prolly fast on a QA50).

    I'm good with John Curea, but does anybody know anything about Emig's suspension services?

    Flanny, any opinions? :ear
    #12
  13. gaspipe

    gaspipe Wandering Soul Super Moderator

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    Bumping this back up to the top - suspension is important :nod

    I spent a bit of time riding a few loops of varying terrain around PHX on my new-to-me '03 640 Adv. My '01 adventure was softly sprung and underdamped, but it felt a bit better than the '03 - and I have no idea why. It's clear that the suspension is nowhere near where it should be for handling the Adv's weight, fuel load and a heavy rider (I'm 240lbs geared up).

    If I rode prettly slowly, I had a plush ride, but I don't have the self restraint to ride that pace for any length of time.

    I rode some technical stuff, rock, sand, etc, and the general consensus was I had to do something about this asap. It was chronically bottoming the fork - it's a bit unsettling to hear the front knob rubbing the fender while in 6" of sand at speed. The fork would actually bottom while braking hard on pavement. The rear was also pretty odd feeling, but it was hard to pin that down since the fork was so poor. In general, I really couldn't wick it up because the suspension action was so poorly damped and sprung for the weight it had to deal with.

    I called MXTech and talked to them about it. They've done quite a few LC4's, and since it was fairly closeby, we decided to take the bike there and size it up. So down to MXTech I went. After making a lot of measurements and chatting about riding style and such, it was recommended to me to stick with the (original?) rear spring since the static sag numbers were actually quite good, but the shock valving needed to be changed rather dramatically. I didn't check the # on the spring since we decided it was OK. I am assuming it is the 7.0 OE spring.

    Up front, we decided to go with .50 springs and revalve the fork. I declined on the preload adjusting caps on the fork, because quite frankly, for the purposes of what my 640 needs to do, I'll never do it reliably.

    Anyway, even if you're a prettly light fella, and you feel the fork spring rate is OK, the fork needs some valving help to really get the max benefit of the WP. The shock, at least on my bike, appears to be fairly well sprung, but poorly damped.

    My point is, if you're actually sufficiently dissatisfied with the suspension's action to consider re-springing it, you really ought to consider revalving the shock and fork to really take advantage of what the WP suspension really has to offer. Revalved, resprung and the sag correctly set makes a world of difference, but it ain't cheap. It is, as Flanny says, the best thing you can do with the bike.

    Thanks to Flanny's post for making me decide to do it rather than dealing with it as it was.
    #13
  14. cross-country

    cross-country .

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    Great advice, suspension is key to going fast and or safe. If your shock is going to be apart ask for the larger bump stop to be put in, it realy takes the edge off of the hard hit e.g. g-outs, jumps, ect.
    #14
  15. Buckster

    Buckster Banned

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    I'm 205 and have re sprung, everything is good now.
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  16. Velocibiker

    Velocibiker Adventure Antagonist

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    Fork springs? Shock spring? All?


    How, may I ask did you come to know this?
    #16
  17. Buckster

    Buckster Banned

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    The bike is sprung for a 165lb rider.
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  18. Jeff620RXC

    Jeff620RXC Been here awhile

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    If your suspension is too stiff will it effect the turning characterisics on dirt?
    Thanks
    #18
  19. Stobie

    Stobie Mr. Motivated

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    What Buckster said.

    Plus, like GP, I could bottom the front on the brakes. And I couldn't get good sag numbers.

    I ended up with .50 kg/mm springs up front and a 8.0 kg/mm spring on the back. Sag numbers are where they should be.

    Since I'm a cheap-ass, I decided to revalve the front fork myself, using a kit from these toads. Since they apparently know nothing about the version of the WP fork used on the LC4's, they didn't send me all the shims I needed, and repeated emails and phone calls got no response from them. Service after the sale was non-existent.

    Anyway, I decided to try a modified version of their recommended shim stack, using the shims I had, with less than stellar results. The front end is still choppy over little stuff, but handles big bumps extremely well. I didn't have the shims needed to soften it up significantly. Now, my choices are to buy the necessary shims from a third party and revalve, hoping the stack specs I have are good, or punt and send them off to a pro. Still :scratch .

    The upside is that I learned a lot about my forks. The mechanics of revalving a fork are quite simple. The trick is knowing what shim stacks to use. I could probably change the stacks in my base valves in about an hour. Getting in to change the midvalve and rebound stacks would require complete disassembly, and would probably be a good rainy afternoon w/ a sixpack project. The Fabtech kit only changes the base valve stack, and I don't have midvalve and rebound stacks for this bike, so I'm leaning toward sending the forks off. The suspension shops are making money off their knowledge, not their labor or materials.

    On the back, I just changed the spring and adjusted the clickers, and I'm satisfied. Gary Emig, and a guy at Factory Connection (Aaron?, Adam?) both told me that although the forks need help, the rear shock on the LC4's does not need to be revalved. My experience supports this.
    #19
  20. Velocibiker

    Velocibiker Adventure Antagonist

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    I was just worried :evil that it was simply bad settings on your part. Too many people simply don't set the front and back correctly and blame the bike on poor performance. Many times, it's simply a lack of proper set-up and maintenance.

    After I rode a friend of mines street bike (it rode like crap), I asked what his suspension settings were and when was the last time he serviced the shock & forks. The "deer in the headlights" look was all I needed to know :D.

    Anyway, glad you got it where you like it!!
    #20