125-200cc CR125 spring rate question

Going to put my son on a 2012 125 and he only weighs 120 lbs. So, does anyone here have a recommendation on spring rates? Thanks.

On my bike, I get Vinduro's sag numbers with the stock fork springs and a 6.3 rear spring. I weigh 215. I was thinking stock shock spring might get him there, but the forks have to need a lighter rate. It's for offroad use. Thanks.

didi i read that right? 6.2 I am 195 woods rider and 5.4 is perfect for me

Yes. I wonder if there are any linkage/swingarm differences between the 2004 and 2012...

This is from Vinduro's set up thread. Must be a difference in bike geometry.

I weigh about 180lbs neked. I am using a .40kg fork spring and a 6.0kg shock spring. That is on my 2011 WR150. Stock fork springs are .42kg.
Stock shock spring is 5.0kg. Hall's installed a 5.4 spring when they serviced my bike. It wasn't close. I had little to NO static sag. Hall's was great about working with me and exchanging springs ( I didn't ride with them till I had the correct one). My fork sag stock wasn't nearly enough. I went down to a .40 and got 40mm static and 75mm rider sag.... PERFECT ! On the rear I was baffled as I kept going up. Jay Hall did take out about 25% of the high speed compression valving. Barely enough. Jay weighs 215lbs and says he uses a 6.8kg. spring. I think that maybe a bit much but I don't know what his sags are. When I got up to 6kg my sags worked out perfect. 30mm static and 101mm rider sag. I don't know what the leverage ratio is on the old frame vs the new frame. But my bike handles SO good, I can hardly believe it. Turns on a dime. Is stable and the front end sticks like glue. You may need to cut a new preload spacer for the forks . It is BELOW the spring. I used a paint stir stick to get it out. Get a PVC Heavy wall to cut new spacer out of if needed.

I ran a 5.4 on my 09 as well, was perfect. I think Vinduro like the stink bug affect (high int he rear) for the tight eastern woods. I also found .44 to be perfect for the front for me. To each his own.

No stink bug effect on my 6.3!!! Nice and plush. But back to the question, what fork rates for a 120 pounder?

We'll start there! Thanks for the effort!

I've got two 5.0 springs. I'll let you know about the 4.8 soon.
Thanks.