Sign in to follow this  
Followers 0

Compression & rebound DRZ400 suspension


bmwpowere36m3

yeah I know a lot of you are just going to say look it up there are tons of threads about this already. BUT I already have and I have looked through a lot but don't really understand a lot of it, im looking for 2 things

1. a solid and simple explanation of rebound and spring rate all that

2. a recommendation of "cheep" fixes.. I called a local shop and I don't want to pay 600+ for them to change springs and revalve.

(not just being a cheap a$$) I am looking to upgrade to a new bike in the next year or two so im tired of dumping money into it.

im replacing my fork seals this weekend and I figured if I was going to have them open I minds well try messing with it

with all gear im about 230 and I ride street... if anybody has any clicker info or anything with shims stacks with similar weight would be great

thanks

1. Compression & rebound are pretty self-explanatory. Compression is when the suspension collapses/compresses and rebound is when it extends/rebounds. Most dirt/trail/enduro/mx bikes have adjustable (to a degree) suspensions. Generally the external adjustments include: low-speed compression (on forks & shocks), high-speed compression (usually only shocks), low-speed rebound (on forks & shocks) and spring preload (on forks & shocks). Internally damping is adjustable via shim stacks, bleed ports, pistons, etc…

Generally low-speed compression and rebound are adjusted with what are known as "clickers" (on the DRZ they look like flat-headed screws, with only the head visible). When you adjust them, you move a needle (right in image below) that sits within an orifice (left in image below).

13-MAXclks.png

Under low-speed movement of the suspension, some of the fluid inside moves through these orifices. By adjusting the clicker "IN" (generally clockwise) you partially close off that orifice. The more you adjust "IN" the more it closes the orifice. By closing the orifice, it takes more energy for the fluid to pass through because essentially you are making the orifice or hole smaller. So for compression it makes the suspension collapse slower (feels firmer) and for rebound it makes the suspension extend slower. The inverse is true when you adjust the clicker "OUT".

It's important to note, that the range of these clickers is limited. If you find yourself at the limits of their adjustment, then you need to revalve the suspension.

Spring rate, is a way to quantify a spring and it simply means the amount of force it takes to compress the spring x amount of inches. So a stock DRZ400S/SM rear spring is 5.5 kg/mm, meaning it takes 5.5 kg of force to compress the spring 1 mm. If the spring is linear, then it'll take an additional 5.5 kg to compress another mm and so on (11 kg for 2 mm, 16.5 kg for 3 mm, etc…).

2. At 230 lbs you need firmer springs both for the shock and forks. That'll run you around $200, no adjustment will compensate for springs that are way too soft for your weight. And no, adding more preload is not the answer… Then as far as re-valving, if you're a DIY kind of guy, you can make changes to improve the damping (I did myself). You will however need a few shims to make those changes as the stock valving is very soft.


Sign in to follow this  
Followers 0


User Feedback


There are no comments to display.



Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


  • Similar Content

    • By Bryan Bosch

      Rockstar Energy Husqvarna Factory Racing Rally Star Earns Third Overalll at the 2018 Edition of the Event in Morocco
      April 20, 2018 – (Motor Sports Newswire) – Determined to wrap up his week-long adventure in Morocco on a high, Rockstar Energy Husqvarna Factory Racing’s Pablo Quintanilla has topped the fifth and final stage of the Merzouga Rally to secure a solid third overall in the event’s final overall standings. Continuing to make progress Andrew Short has claimed a spot inside the top 10 in the overall.
      Featuring a mass, motocross-styled start in the dunes of the Merzouga Desert, the fifth and final stage of the event saw Pablo Quintanilla put in a dominant performance. Posting the fastest time for the day, the Chilean rally star solidified his strong third position in the overall standings.
      Putting in his best individual stage performance Rockstar Energy Husqvarna Factory Racing’s Andrew Short crossed the line in eighth position. Wrapping up the Merzouga Rally 10th in the overall, the American is content with the progress he made during the week in Morocco.
      The Rockstar Energy Husqvarna Factory Racing Team will return to action at the third round of the 2018 FIM Cross-Country Rallies World Championship, the Atacama Rally in Chile on August 11/19.
      Pablo Quintanilla: “Today was a really fun stage. We had the motocross start and it was good to battle with the guys from start to finish. I got off to a good start but five or six kilometres into the stage I had a small crash that dropped me back a few positions. Then I had to push until the end and 10km before the finish I got the lead back and was the first to cross the finish line. It felt really nice to win a stage that way. Overall, I’m satisfied with my third position in the overall. This was a tough race with tricky navigation and to be on the podium is always good. We continue to gather experience and look ahead in the races to come.”

      Andrew Short: “I really enjoyed this week in Morocco. Especially this last day was really fun, bringing back memories from my days racing motocross. Before the flag dropped the nerves were there and I was maybe a bit late off the start. It was a good experience racing alongside the fastest guys in the dunes and being able to see their pace. The adrenaline kicked in and I had some really good fun. Overall, the week has been great for me. I enjoy the atmosphere in rally racing and I feel I am improving, getting closer to the top guys. I might still have a long way to go but I understand it needs to be done step-by-step. This week was a positive step in the right direction.”
      2018 Merzouga Rally – Stage 5 Provisional Classification
      1. Pablo Quintanilla (Husqvarna) 38:12 
      2. Kevin Benavides (Honda) 38:15
      3. Toby Price (KTM) 38:18
      4. Lorenzo Santolino (Sherco) 38:36
      5. Joan Barreda (Honda) 38:38
      6. Ignacio Cornejo (Honda) 38:54

      8. Andrew Short (Husqvarna) 38:56
      2018 Merzouga Rally – Final Overall Classification [Provisional]
      1. Joan Barreda (Honda) 13:28:19
      2. Kevin Benavides (Honda) 13:34:29
      3. Pablo Quintanilla (Husqvarna) 13:39:44 
      4. Franco Caimi (Yamaha) 13:47:08
      5. Ricky Brabec (Honda) 13:48:23
      6. Toby Price (KTM) 13:49:23

      10. Andrew Short (Husqvarna) 14:29:44
       
       
      Husqvarna Motorcycles. Tradition on two wheels since 1903.
      Husqvarna Motorcycles are widely known and respected in the off-road world for a heritage of competition and numerous motocross and enduro world championships. Originally founded in Sweden in 1903, Husqvarna Motorcycles have been designed and manufactured in Mattighofen, Austria since 2013.
      Rockstar Energy Drink
      Rockstar Energy Drink is designed for those who lead active lifestyles – from Athletes to Rockstars. Available in over 20 flavors at convenience and grocery outlets in over 30 countries, Rockstar supports the Rockstar lifestyle across the globe through Action Sports, Motor Sports, and Live Music. For more information visit: www.RockstarEnergy.com
      Source: Husqvarna Motorcycles GmbH

    • By Inuviktoo
      Hi All,
       
      I was just given a red Suzuki "quadmaster" 50.  This is the 2 stroke oil injected quad with red plastics.  I have a couple of questions that I am hoping for some help with:
      1. Any advice on where to find the VIN #?  I would like to figure out what year it is so that I can properly order parts. The only numbers I have located are on the engine at the base of the cylinder on the pull-start side.
      2. What is everyone's actual experience with Chinese-made carbs and top end kits?  The reviews on Amazon and Ebay are either "total garbage" or "best thing ever". I don't know what to think.
      3. This quad has a ton of hours on it, but it does run ok.  The carb seems pretty tired, and leaks fuel like crazy.  I have not torn into it yet to see what the float condition is.  I'd love to hear folks experience with carb rebuilds again vs. aftermarket replacement.  I am also not seeing a lot of piston's available.  RMATV does not seem to even list an OEM option from what I can tell.  Is there a best option for top end freshening?
      Thanks for any advice or help.  I'm trying to keep this "free" quad as cheap as possible while trying to get it to run well for my kids. 
    • By Acriswell
      Hey All!
      I recently traded a bike for my new 1973 Suzuki ts400. The bike has been sitting awhile, after doing the normal, carb gaskets cleaning, checking spark, then realizing the ignition system (pei) needs a timing light to check timing, i tried to start it up with a little bit of premixed gas just to see where its at... the only thing i get get the ol girl to do its backfire out of the carb (no elbow or airbox) it seems like its got hell of a compression to it but i removed the exhaust to take a peek at the rings. It seemed to be scored up, so i took some pics. Anyone know what the compression is supposed to be? Any help is greatly appreciated! 
      Thanks, Austin.

    • By Anthony Bryant
      Hey so i have this idea of building an rmz450 from the chassis up. Does anyone have there take on this? I have time so thats not an issue. Im gonna start with an 08 frame then go from there.  
    • By ClutchinChrisG
      I've decided to attempt the mid-body gasket replacement on my vintage 2000 slant FCR carb, stock on the DRZ 400 E. If you are like me you have scoured the forums for info on doing this service but found maybe 2 or 3 pictures of a taken apart FCR, dead end threads, and tons of negativity. 
      BUT! Is it really that difficult of a repair to perform correctly? Well I have had my carb on and off at least a dozen times, trying different jets, cleaning, etc. For the last 3 years I've been getting by with the coast enrichener circuit bypassed to at least get enough fuel in the idle circuit to run ok. But it just wasn't working anymore. I could clean the carb out and get it to run for a little while, but after sitting it wouldn't start again. I tried ordering a refurb FCR-MX over a week ago and the guy has gone MIA and nothing shipped. I ordered from keihin-fcr.com. I would advise avoiding... But will update if I hear back and he has a decent reason for the delay. Anyways, it made me seriously look into the "unserviceable" midbody gasket. I mean, you can buy the gasket here: https://www.ebay.com/i/401380298480?chn=ps
      So today I ripped the carb apart again, but this time to the very last fastener, separating the carb bodies. I even found my smoking gun, in the one picture with the hoop thingy removed you can see the gasket has expanded and spilled into a passageway. This passageway leads directly to the pilot jet, blocking it's flow. Though as you can see every rubber piece inside is completely trashed. Which makes sense, do you really expect these gaskets to last 20 years? Or in this case 18? If you have taken apart your FCR and went, wow that fuel bowl gasket is recked yo! I need a new one! Well you can bet your mid-body gasket looks the same. Really I see no reason I couldn't get this sealed back up with a new gasket and some fuel-proof RTV to replace the epoxy seal around the edge. Why wouldn't it work? Just doesn't make sense to me all the negativity you find toward this repair.... But I haven't finished yet so who knows if it will actually work on the bike. But I think it'll run like new when I'm done. I hope it works out for me and I can inspire some others who would otherwise be forced to buy an 800 dollar carb to do this repair instead.
      Wish me luck!