Two Stroke Motocross

Two Stroke Motocross Forum => Technical => Topic started by: 6IX on May 17, 2012, 11:12:21 PM

Title: YZ250 Spring Rates
Post by: 6IX on May 17, 2012, 11:12:21 PM
Figured this might be a good place to ask what everyone;s experience has been with different spring rates on late model YZ250?s.  Post up any rates, specs, front and rear that you?ve tried and how they worked for you, what kind of riding you do, what year YZ, etc.

I am pretty much narrowed down to what I want to do, but there was a bit of a debate when it came to the rear titanium spring being replaced with a steel spring (I hear an equal rate steel spring feels / is slightly softer).  Planning on sticking with a replacement Ti spring that I can get a great deal on, and going with a 5.1 (stock is 4.9) while taking the forks from their stock .44 to a .45 or .46
Title: YZ250 Spring Rates
Post by: scotty dog on May 18, 2012, 12:37:24 AM
Just on the Ti spring, arent they really expensive compared to a steely? I just read the may issue of MXA and Jody does up a YZ 250. Have you read that? $600 he claims  :o :o whoa
Title: YZ250 Spring Rates
Post by: 6IX on May 18, 2012, 12:41:09 AM
Yep, they are ~$600 from DSP (havent priced Yamaha OEM which I'm assuming is KYB made) but I'm sure it about $600 as well.

I have a line on barely used one for under $100.
Title: YZ250 Spring Rates
Post by: scotty dog on May 18, 2012, 01:35:02 AM
Yep, they are ~$600 from DSP (havent priced Yamaha OEM which I'm assuming is KYB made) but I'm sure it about $600 as well.

I have a line on barely used one for under $100.
thats a score
Title: YZ250 Spring Rates
Post by: msambuco on May 22, 2012, 11:23:47 PM
I did full Factory Connection on my 08 YZ250. I went with their advice and upped the spring rated at both ends. Everything worked better except on big bumps where the rear end would kick. The clickers did not help much. I left everything alone untill I rode at my favorite riding area which I ride very fast in sandy whoops with lots if tight turns (woods). Here I realized the back truly was oversprung. I put the stock spring back on the rear. I left the heavier springs in the forks since they worked great. Now all is improved over stock (not by a whole lot since it was so good to begin with) and handling is exactly like stock. I did make several changes on the front and rear clickers to get it working right with the softer spring. My 2 cents.
Title: YZ250 Spring Rates
Post by: msmola2002 on May 23, 2012, 04:15:33 AM
Most importantly

How much do you weigh? Spring rates for a 120lb girl riding in the women's class won't mean jack if the rider is a 240lb fatty.
Title: YZ250 Spring Rates
Post by: 6IX on May 24, 2012, 06:47:26 PM
I did full Factory Connection on my 08 YZ250. I went with their advice and upped the spring rated at both ends. Everything worked better except on big bumps where the rear end would kick. The clickers did not help much. I left everything alone untill I rode at my favorite riding area which I ride very fast in sandy whoops with lots if tight turns (woods). Here I realized the back truly was oversprung. I put the stock spring back on the rear. I left the heavier springs in the forks since they worked great. Now all is improved over stock (not by a whole lot since it was so good to begin with) and handling is exactly like stock. I did make several changes on the front and rear clickers to get it working right with the softer spring. My 2 cents.

Do you know what spring rates you used, and did you use a steel or Titanium replacement spring in the rear?
Title: YZ250 Spring Rates
Post by: msambuco on May 24, 2012, 07:31:38 PM
Forks stock .44, went to .45. Works perfect
Shock stock 4.9, went to steel 5.4. Not so good.
Rider: 49 year old 220lb, decent ability all around, former MX racer, can still beat my kid on his RM125 but not for much longer.
Title: YZ250 Spring Rates
Post by: 6IX on June 03, 2012, 10:27:41 PM
Forks stock .44, went to .45. Works perfect
Shock stock 4.9, went to steel 5.4. Not so good.
Rider: 49 year old 220lb, decent ability all around, former MX racer, can still beat my kid on his RM125 but not for much longer.

Thanks.  I?m questioning going to .45?s or .46?s on the forks. I hear there can be a lot of variance in ratings though, so when my manual lists the standard spring as .438, I?m assuming that?s basically a .44, and the next stiffer listed is a .449 which I?m assuming is a .45 rating, that might not make a noticeable difference if the spring ratings a little off.

Without riding it, I?d tend to agree that a 5.4 rear spring would be way too stiff to go with .45 fork springs.  Did Factory Connection suggest the 5.4?  Did you change it out for a softer rate yet?