Jump to content
Sign in to follow this  

2008 yz450 shock rates

Recommended Posts

Hey guys, I was just wondering if anybody knows spring rates on the new yz450. I am about to purchase one and I read that you can do all the tuning you want, but without the proper spring rate on the back you will never get the bike working as well as it can. I am 155 lbs, will i need to put a different shock spring on there? I am trying to learn to setup my own suspension. Any suggestions would be appreciated. Thanks! :ride:

Share this post


Link to post
Share on other sites

chances are unless you do sx they will be too firm for you, but you can pick up some 250f springs on ebay i bet.

Share this post


Link to post
Share on other sites
Hey guys, I was just wondering if anybody knows spring rates on the new yz450. I am about to purchase one and I read that you can do all the tuning you want, but without the proper spring rate on the back you will never get the bike working as well as it can. I am 155 lbs, will i need to put a different shock spring on there? I am trying to learn to setup my own suspension. Any suggestions would be appreciated. Thanks! :ride:

'06 and '07 were the same .48kg/mm fork and 5.5kg/mm shock.

It won't hurt to try to set the sag and ride it first. .44kg/mm and 5.0kg/mm would work well depending on how fast you are

Share this post


Link to post
Share on other sites
Hey guys, I was just wondering if anybody knows spring rates on the new yz450. I am about to purchase one and I read that you can do all the tuning you want, but without the proper spring rate on the back you will never get the bike working as well as it can. I am 155 lbs, will i need to put a different shock spring on there? I am trying to learn to setup my own suspension. Any suggestions would be appreciated. Thanks! :ride:

I just got a 08 YZ250F and I'm curious about the spring rates too. I found on race-tech website that a stock 250F is set-up for 84kg rider. I'm about 74kg with gears on so I'm wondering will it make a world of difference when I'm just 10kg short? :thumbsup: Maybe I should just try set the sag to see how it goes first? Advice anyone?

I hope this link will be useful for you http://www.racetech.com/evalving/english/Srchpr.asp?bikeid=1394&manufacture=Yamaha&model=YZ450F&year=2008&TABLEINFO=dirt&langname=english

Says 08 YZ450F's ideal for 170lbs rider. You can check what's the ideal rate for your weight as well. But I guess it all comes down to what sort of riding you do and how hard you ride which plays a part too yeah?

Share this post


Link to post
Share on other sites

you will benifit from the correct springs.

Share this post


Link to post
Share on other sites

5.4 for the rear, .47 on the front with a 2.0 ICS. Fork level from the factory is 350cc.

I have the values for the other YZs and for KXs as well if anyone needs them.

Share this post


Link to post
Share on other sites
5.4 for the rear, .47 on the front with a 2.0 ICS. Fork level from the factory is 350cc.

I have the values for the other YZs and for KXs as well if anyone needs them.

are you sure? The manual claims 5.5 for the shock and RacTech says 5.3..:prof:

Share this post


Link to post
Share on other sites
are you sure? The manual claims 5.5 for the shock and RacTech says 5.3..:prof:

Well...it's always worth double checking.

Here's what I found.

The shock spring is a 54N/mm which is a 5.5 kgf/mm. This is the 1C3-222212-12-50 that you see listed in the manual and on the fiche.

The fork spring is a 4.6N/mm which is a .47 kgf/mm (.469). This is listed in the manual as the 2S2-23141-L1 as well as the fiche.

The free-piston spring is a 20N/mm or a 2.039kg/f-mm, which is what KYB is reporting as the manual and fiche don't cover this.

I think the numbers get a little twisted when they move back and fourth between Newtons and kilograms-force (kgf) and when people start to round things up or down.

I'm not sure what's up with Race Tech other than fact that sometimes they list THEIR replacement spring (and American made version) as an OEM value, and not the actual factory spring value.

Keep in mind that measuring a spring based on what it does within the first few millimeters is never a full representation on what it's going to do throughout the stroke. So you can't really match up a 5.3 spring from Race Tech with a 5.3 from KYB anyways.

If I missed something somewhere let me know. Sometimes I get my notes a little mixed up so it's good to be doubled checked.

Share this post


Link to post
Share on other sites

DaveJ,

I greatly appreciate the info....I think I have a case of OCD when it comes to my bikes. I dropped off my suspension at a reputable shop in my local area to be serviced and I figured springs for my weight also. It just seems like everybody's numbers are a hair off on spring rates for my weight, but what you posted would make sense why the numbers are off.

Thanks

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

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

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×