Measured the white spring today as well as one can measure an installed rear spring.

Spring: 234mm with Preload at 111mm (range 101mm - 123mm)

The red spring is 235mm (free). So I'm guessing that the white spring free would be 244mm or a bit more as there should be a minimum of one turn of the adjusting nut.

Another day when I get a bit more ambitious I'll install the red spring and report back. The next few nice days (if we get any) I'll be riding (moto or MTB) as we've had a LOT of rain for weeks now with just a few short breaks. Quack. Quack.

All's ducky.

 

Lots of uncertainty on late model spring lengths. My '12 250s springs are 415mm as mentioned earlier.

Moto Pro referred me to Cannon. They were the only manufacturer who knew exactly what was needed. Seven day lead time. Mine are in transit right now .

Installation: A breeze if you buy a couple of ratcheting tie downs from your favorite discount store. One for each fork hooked at the handlebar cradle and the bottom of the fork. I'll post some pics of my install.

 

Pics

 

All done

 

fwiw, the 300 and 250s spring rates are the same rate but the S model were a little longer for more preload, this was just an adjustment for ride height of the heavier weight S model.

As you get up into heavier rate replacement springs it's not desirable to have all that extra preload built into the spring, the fork will have too much top out and too little ride sag. Better to have a 300 length spring and add a spacer if need be to set sag IMO. Motopro should be factoring this in if they are not.

the stock rear springs are wound bee hive, or smaller toward the top. Aftermarket springs are not so touch the airbox boot ribs and clamp, Hasn't seemed to be a problem on my bike but thought I'd mention it in case you notice it. Also with a heavier spring you may preload it less (so is longer) and it may be the lock rings that you feel touching the airbox boot.

 

How did the new springs work? I have a 2010 klx250s and I am trying to do the same thing,so far I havent been able to find the right spring

 

Rides like a different bike after both springs replaced. You can use the front brake without feeling like you're gonna pitch over the front of the bike.

Initially I set all dampening adjustments at Kaw recommended levels which was too bouncy. Now I have front and rear CD 4 clicks out from the seated position (more dampening). That adjustment really sweetened the ride.

I'd say this mod has the greatest impact on the fun-factor of this bike!!

Cannon Racecraft is the go-to source for springs IMO.

 

Can you post the spring rating you bought and part numbers?

 

Forks springs are rated at 4.6. These were made to order by Cannon - fork springs for 2012 aren't stocked anywhere.