Newbie suspension question


17 replies to this topic
  • IAFF74

Posted May 13, 2011 - 03:26 AM

#1

ok, I just bought an 09 yz450f a month ago. Lots o fun BTW! I'm 6'-0" 230lbs and I know i am running on the stock front forks, the rear spring has one that suited for my weight(a friend of mine gave me his racetech off his bike) everything feels pretty good to me but I have been reading here and it seems that their is a night/day difference once you get your suspension dialed in for you. First, when referencing Re-valving do they mean changing the shims? If so, could I possibly find a rider thats in my weight range and mimic theirs? second, can I start with a fork spring and maybe add a little fluid? I'm all for spending money but am also on the frugile side. Thanks for the info

  • crf450319

Posted May 13, 2011 - 07:22 AM

#2

Hey,

First thing I'd do is get a set of fork springs suited for your weight, I'm 210lbs and went to aftermarket springs front & back - made a very noticeable difference. Diverse Suspension Products sells the springs for a very reasonable price, as far as I remember quite a bit less than Race Tech etc. The fork springs are $89 shipped within the US.

I'd think that putting the Race Tech shock spring on the back, and leaving the stock fork springs would make the bike feel less balanced ? My guess would be that the front end would feel worse with that RT spring in the back ?

Yep, with a re-valve companies change the base valve (which controls comp. dampning) and they re-shim as well. I think they usually leave the mid-valve (controls rebound) alone but I could be wrong. I'm guessing if you throw engough $$ at them, they'd change the mid-valve to suit your ability/weight ? On the rear end, they replace the piston in the shock and re-shim as well.

And yes, you could copy someone's shim stacks and it would work so long as their settings work for your ability/weight.

But, like I said... the very first thing I'd do is put a set of springs in the forks for your weight, the stockers are for someone who weighs 175/190lbs. I run Intermediate and MX only, I run 5w fork oil and put 360ml in the outer tube.

  • grayracer513

Posted May 13, 2011 - 08:09 AM

#3

First thing I'd do is get a set of fork springs suited for your weight, ...

That's good advice. The suspension has no hope of working correctly without the right support for the rider's basic weight. Well over half of all riders outside of the 170-190 pound range will be happy with the stock YZF stuff with no more than fluid and clicker changes after the springs are right.

...with a re-valve companies change the base valve (which controls comp. dampning) and they re-shim as well. I think they usually leave the mid-valve (controls rebound) alone but I could be wrong.

What gets done will vary from one company to another based on differing theories of what the problems are and how to deal with them.

The mid valve does not control rebound, the rebound valve does. The confusion may be from the fact that the rebound valve stack is on the opposite side of the same piston where the mid valve is located. Some suspension outfits will leave these at least mostly untouched, but not many will leave them stock. Dave Johnson at SMART Performance completely revises the function of the mid valve, and gets great results from it.

But the first thing you should do is to change those front springs, as earlier said. You'll be much happier with the bike, and you can do more from that point if you think you need it.

  • IAFF74

Posted May 13, 2011 - 10:56 AM

#4

Thanks everyone for the info. Consider it done.

  • IAFF74

Posted May 13, 2011 - 10:56 AM

#5

buying new front springs that is

  • Squidless

Posted May 13, 2011 - 11:10 AM

#6

Like you, I like to see what I can do while spending as little as possible.

Unfortunately, there's no cheap way to increase the spring rate, so you may have to buy some. I've decreased the spring rate by grinding the OD of the spring, but you need to go the other way.

Once you have the right springs, revalving basically means adding and subtracting shims. Guys like Dave (mentioned above) do some fancy things in there, but the basic stuff is nothing you can't do yourself.

Valving is somewhat of a user preference type of thing. If you think it's too harsh, take shims out. If it's too soft, put shims in.

I'd recommend buying Race Tech's Suspension Bible. It was the best $25 I spent on my suspension projects. It shows you how to take it apart and put it back together. It also gives the theory of what all of the different parts do and gives you tips on how to test it.

  • Bobbed06

Posted June 06, 2011 - 07:22 PM

#7

Bumping an older thread as I am considering buying the DSP springs front and rear for my 03 YZF as I am way over the weight limit of stock stuff.

I would like to get feedback on the DSP springs from Ebay seller Gnarly MotoX. Just wanted to see if anybody has any good or bad to say about them is all. Any feedback appreciated.

  • Polar_Bus

Posted June 07, 2011 - 02:53 AM

#8

I was at the other end of the suspension delima. I only weigh 155 lbs, and my '07 was valved stiff from the factory. Perfect for agressive amatuers or experts, but the other 75% of us slow guys were complaining of an overly harsh suspension. I first tried softer Factory Connection springs both front and rear. The bike was better in the rear, but honestly the front felt pretty much the same even with softer springs. After a year of still not being happy I had an awesome conversation with FC's tech support and they explained to me how you really need a re-valve when you also re-spring. Always keep in mind suspension valving does not directly alter "firmness" or "softness" within your suspensions feel. Valving simply alters the speed at which your suspension reacts to absorbing or retracting from a bump. When you re-spring now your valving is altered as well. Long story short after FC re-valved my suspension and swapped fork springs a 3rd time, my suspension is now night and day difference from just swapping springs myself. Trust me, it will be the most awesome $800 you will spend on your bike ! :ride:

  • Bobbed06

Posted June 07, 2011 - 09:35 AM

#9

I will just change the spring on the rear shock and see where I need to go from there in regards to oil weights or valving.

On the front I will do the same. My bike is still new and I am sure the OEM fluids will provide a useful starting point as to what fluids to choose for fine tuning.

I am looking for product feedback on the DSP springs sold on EBAY.

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  • crf450319

Posted June 07, 2011 - 06:47 PM

#10

I am looking for product feedback on the DSP springs sold on EBAY.


I've got DSP springs in my '09, and I think they're awesome. I called DSP and ordered direct.

  • Bobbed06

Posted June 07, 2011 - 10:00 PM

#11

I've got DSP springs in my '09, and I think they're awesome. I called DSP and ordered direct.


Did you use them front and rear? Did the rear spring hold your race sag settings fairly well after a few rides once it broke in?

Thanks for the feedback I would definitely prefer to deal directly over EBAY any day. :ride:

  • crf450319

Posted June 08, 2011 - 05:41 AM

#12

Did you use them front and rear? Did the rear spring hold your race sag settings fairly well after a few rides once it broke in?


Yep, I installed their springs on my shock and forks. I talked to one of their techs on the phone and he suggested 0.50kg/mm fork springs and a 5.8kg/mm shock spring - I weigh 210 Lbs, ride MX only and race in B or Intermediate. But if you call and explain what type of riding you do and what you weigh, they'll set you up with the proper springs.

I thought the stock suspension was good, and it is.. but on big hits is where the DSP springs really shine.

My sag hasn't changed since I set it, you will LOVE these springs ! For the cost, I don't think there's a better mod you can do. Unless you fit into the OEM Yamaha spring rate..

  • Bobbed06

Posted June 08, 2011 - 07:55 AM

#13

Yep, I installed their springs on my shock and forks. I talked to one of their techs on the phone and he suggested 0.50kg/mm fork springs and a 5.8kg/mm shock spring - I weigh 210 Lbs, ride MX only and race in B or Intermediate. But if you call and explain what type of riding you do and what you weigh, they'll set you up with the proper springs.

I thought the stock suspension was good, and it is.. but on big hits is where the DSP springs really shine.

My sag hasn't changed since I set it, you will LOVE these springs ! For the cost, I don't think there's a better mod you can do. Unless you fit into the OEM Yamaha spring rate..


Thats what I needed to hear, I will talk to them and get the proper rates for my weight. I definitely dont fit into the stock spring window at 265lbs! Even at lean and mean race weight I am at 225-230lbs and I ride at a fast B pace as well. I do however go big and sometimes short or flatland when out freeriding and I dont want to deal with improper springs whenever I do that.

Again, Thank You for the feedback. I didnt want to drop a bunch of dough on springs, without someone else confirming quality.

  • crf450319

Posted June 08, 2011 - 12:01 PM

#14

I do however go big and sometimes short or flatland when out freeriding and I dont want to deal with improper springs whenever I do that.


Like I said, that's where any spring suited to your weight will really shine and the DSP stuff won't disappoint ! I've over jumped a 110' uphill at a buddy's track, and come up short on it as well. It's a big hit, and whenever I've screwed it up I've thought "I'm going to leave a big crater when I land", only to ride away un-scathed... This is the jump in question :

Posted Image

I rode another friend's new '09 yz450f 2 days ago, took it pretty easy and the stock springs felt pretty good. But I know for a fact that mine feels much better on the big nasty hits, in comparison to his stockers.

I'd pretty much guarantee that you'll be happy with your purchase :ride:

  • Bobbed06

Posted June 08, 2011 - 01:07 PM

#15

Thanks again, you definitely understand where I am coming from. No doubt about that. DSP springs will be on my bike.

  • grayracer513

Posted June 08, 2011 - 01:53 PM

#16

IMO, the highest available quality springs for a Yamaha are KYB. DSP and Eibach are next.

  • tl1000rlt

Posted June 21, 2011 - 10:28 PM

#17

DSP does not have springs for a 03 450. I have looked at race tech and pro circuit and all they offer is .48 for the front. Thats only one step over stock and I need .52 for my weight. Anyone know where I can get the right springs?

  • grayracer513

Posted June 22, 2011 - 07:12 AM

#18

Check with






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