Front end feel & stability...



34 replies to this topic
  • Bturner

Posted December 03, 2013 - 03:42 PM

#21

Yea I forgot you said that. When I was in the woods I couldn't remember the settings you said. I'll try that this weekend. I talked to DaveJ on the phone & told me to email him where it's at & exactly what I'm feeling. It was valved for 175-180# B hare scrambles, which is almost where im at. The sag is set at 98mm, which I think this weekend I'll try it at 105 & see how that feels. It still feels a little outta balance feeling, but that may just be settings, not really sure. If I can't get it to where I want it, I'll just get it revalved again by my local suspension tuner that does my suspension normally.

  • grayracer513

Posted December 03, 2013 - 04:46 PM

#22

Is this a bike that's already been done by SMART, or with one of Dave's kits?  There's a fix for that issue if it was done a while back.



  • Bturner

Posted December 03, 2013 - 05:54 PM

#23

It has a kit I guess. The previous owner ordered a build sheet & the internals, springs, etc & did it himself.
Btw, I have the build sheet. If I posted it, would you be able to comprehend what's going on?

  • grayracer513

Posted December 03, 2013 - 11:06 PM

#24

If it's the same situation I think it is, then yes, probably so.

  • Bturner

Posted December 04, 2013 - 05:14 AM

#25

Ok. I'll get it later after work.

  • Bturner

Posted December 05, 2013 - 06:40 PM

#26

If it's the same situation I think it is, then yes, probably so.


Gray, do you want me to pm you the sheet? Does this fix you speak of involve a revalve? Because that's what it's looking like. I think the valving is a bit stiff for the majority of the riding I do. It would be perfect for the GP I run once a year, or the few times I hit the MX track. But even for the HS I do, I think it may be a bit to aggressive for the woods I'm riding. I'm no A-B guy either.

  • grayracer513

Posted December 06, 2013 - 07:49 AM

#27

Sure, PM it if you like.  If that doesn't work, send it to the Full Contact link in my sig.

 

What I think is going on is that your bike may have an earlier version of the "Dual Spring Dell Taco" mid valve set up, and/or one originally set up for MX only.  The forté of the Dell Taco is its ability to absorb the big hit.  I still find myself wondering where all the energy goes, exactly, when I slam a cross cut or something out in the badlands.  But they had a kid of built in harshness over little stuff that mostly doesn't bother the MX crowd much, but gets annoying quickly out in the open desert. 

 

There's a fix, and yes it involves a little shuffling of the mid valve stack and adjustment of the spring preload in the valve itself.  Makes a huge difference in the feel though, and without compromising the overall function of the setup.



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  • vic2340

Posted December 06, 2013 - 08:35 PM

#28

It has a kit I guess. The previous owner ordered a build sheet & the internals, springs, etc & did it himself.
Btw, I have the build sheet. If I posted it, would you be able to comprehend what's going on?

uuwwwww... After hearing this I know that tinkering with the suspension clickers probably wont get you anywhere near happy for what your doing. Do yourself a favor and send your suspension out, I recommend going with someone reputable like RG3, Factory Connection, or Pro Action. The money you pay them is a small fee for what they can do for you. A good suspension revalve and set up is extremely hard to accomplish yourself. When you pay them they guarantee their work, and in my opinion there is no better upgrade to any bike. Good suspension inspires a lot of confidence and can make you really melt into your bike as one, man and machine.



  • Bturner

Posted December 06, 2013 - 08:55 PM

#29

Hey man, I couldn't agree more.  I've had suspension jobs done before on my bikes.  There's local tuner I use, pretty much everyone around here does.  The most I'll ever do with mine is change the oil & springs out.  Valving is something I don't wanna bother getting into.  I'll leave that to the professional w/ 20+ years experience.  I'm gonna take the forks in to get them re valved.  The bike doesn't ride horrible, its just not quit there for what I want.  I got the sag almost at 100mm & 'm going to soften it up all the way this weekend & work back out like Gray mentioned.  I'm gonna move the forks down 5mm as well.  Maybe a little more rake w/ help with the pushing.  I went & saw one of the mechanics I use today.  He has the same bike & was telling me what he did to help w/ his, but I know a re valve is whats gotta happen.  I can't hardly stand to ride a bike thats not 100% set up for me.  I just can't do that anymore.  Once I had gotten my 1st suspension job, I have always had to get them done now.  Its night & day on how confident I am w/ myself, the bike & my riding.This is a new bike & it was set up for a guy my weight, but he liked his a bit more aggressive than I do. I am wanting to try Davej or Grays new stack though. I've been wanting to ride different suspension than what I have been.  I Just wanna see what else is out there & how good other suspension can be.

 

Gray, i'm trying to figure out now how to send you my build sheet through a pm.



  • Bturner

Posted December 06, 2013 - 08:59 PM

#30

Gray, I sent you an email.



  • grayracer513

Posted December 07, 2013 - 12:44 PM

#31

Got it. I was right, it's an early build of the DDT design. I'm out in the desert right now, but Sunday evening I'll get back to you with the update for your mid valve.

You up for trying the fork work yourself?

  • Bturner

Posted December 07, 2013 - 03:10 PM

#32

No, that's out of my comfort zone just because I've never done it. I don't wanna mess something up, I'd rather pay the guy them at normally does all my suspension stuff to do it. I've got another question, but it's in the CDI thread. I'll post it there.

  • grayracer513

Posted December 10, 2013 - 08:16 AM

#33

Ok, sorry for the delay, but here's what you need to do to get rid of that harshness over the cobbles and chop.

 

The typical mid valve "floats".  That is that rather than being clamped in place like most suspension unit valves, which are then active the minute fluid pressure bears against them, the normal mid valve is held against its piston by a weak spring and the shim stack runs up and down a small amount (.015"-.050" is typical) on a collar.  This means that the valve offers no resistance to slower stroke speeds, as the stack simply lifts up and allows them without causing any shim deflection.  As the stroke speed increases oil flow becomes great enough that the shims become an active control.  Thus, they start working at mid speeds and up, hence the name.

 

The downside of this that Dave Johnson decided to address is that the transition from float to active valve often comes with a sharp rise in damping resistance, and the resulting pressure spike can be felt as a jolt to the rider.  To eliminate that, the spring force holding the valve stack down was raised to the point where the valve is active immediately as the rod moves in compression, but allows the entire stack to lift when oil flows exceed a certain point as pressure limiting, or "blow-off" function.  This setup is what gives the DDT it's ability to suck up the really big hit. 

 

That was fine for MX guys, but off-roaders who were in on this early, including me, complained of the sort of harhness you mentioned.  That harshness over the little stuff stems from the lack of float.  To correct it without giving up on the rest of the concept, an early cross over is used.  Where, in your mid valve, you have this:

 

20  .11  8

20  .11  8

16  .11  8

14  .11  8

11  .25  8

11  .25  8

17  .30  8

#62 spring

#175 spring

7.3mm collar

8   .50  6

 

You should change to this:

 

20  .11  8

11  .30  8

20  .11  8

16  .11  8

14  .11  8

11  .25  8

11  .25  8

17  .30  8

11  .20  8

11  .20  8

#62 spring

#175 spring

7.3mm collar

<removed 8x.50x6>

 

That will make a world of difference all by itself as it will allow the initial stroke pressure to "ramp up", rather than spike as the small stuff is hit.  Note that the last two 11 x .25's serve to limit the stack lift and the blow-off function by coil binding the smaller spring to keep the fork from blowing through the stroke.  I would also reduce the base valve stack by removing 4 32x.11x6 shims from between the 26 and the 30. 

 

Try that, you'll be much happier.  Read also this thread:

 

http://www.thumperta...97#entry9532997



  • Bturner

Posted December 11, 2013 - 07:06 PM

#34

Gray, I was looking at the build sheet & I found under setting one the spring rates & oil height.

330ml in each fork
.49kg fork
5.7kg shock
It says set up for 175-180 HS B-A rider.

I weigh 200# 5'11". I workout a lot, so it's not that I'm a big guy or a fat guy:), Im just built. spring time I will cut up & get back down to 185-190. Winter I normally try to bulk up. Also, I'm no A or B rider, so the set up seems really aggressive for a 180# guy which would make sense for a more skilled racer. Could this be my problem as well with handling? The forks seems like that's a really stiff rate. Rt said I need .47 & 5.5 I think last time I checked. I have the stock springs to, would that may be something I should entertain? Softer spring rates? I only run 2-3 races a year, all the other time I'm just out carving up trails with the boys, so I really don't need a super aggressive set up. I do like to run my suspension soft. What do you think?

  • YamaLink

Posted December 11, 2013 - 07:34 PM

#35

Adding to the plethora of great info already given, one of my must-checks for front end feel and stability is fork rebound. On top of everything else to check, I like having my fork come up just quick enough - without rebounding too fast which loses front end traction in many types of turns. Like everything else there is a fine line.







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