125-200cc WR 2009 rear spring fit a WR2013 125

hi I weigh 205 lb fully kitted and thing the rear on the 125 is too soft,In the UK you can not get any spring,or aftermarket stuff at all.will a 250 rear spring fit the shock for the 125,my thought is the 250 weighs more so should have a heavier standard spring,which if transfered to the 125 will help.theres a used shock on ebay so that's what I'm thinkng.what do you know???

Might work - don't know. But What I can tell you is that I installed a titanium KYB spring from a Yamaha YZ 250 and it worked. I had to get creative in how I installed the spring because its longer than the stock Sach's spring, but it works great. I have a 2012 Husky CR125, which I'm pretty sure has the same shock as your '13 WR144

JRod did you have to cut it down or just compress it befroe you put it on,what year was the spring from?,cheers dirtdame,is that the '13 WR300/250?,honestly over here you cant get info or buy anything,main dealers are crapp

I can't remember what year it's from... I think it was a 2007 YZ450F now that I think of it - but it's a 5.5 kg/mm spring. My sag is set nearly 'perfectly' and I only weigh 160 pounds. I bet you'd need something closer to 6.0. The YZ KYB spring lengths vary slightly depending on year/model, I think I had the longest they make, unfortunately for me. I think the newer YZ450 spring-rates are closer to 6.0 if you wanted to try that route. Beware though, because the diameter of the spring is slightly larger than the Sach's spring and it could rub on the swingarm/airbox. In my case, it doesn't rub anything because I have a 5.5 kg/mm spring, if you run a bigger spring (like a 6.0 kg/mm), the coils on the spring might be larger, and you could have rubbing issues. I doubt that'll happen though - but figured I should mention it.

DO NOT cut the spring. I installed it by pre-compressing it. I didn't have the proper spring compressor tool, so I got creative. I have a post somewhere on CafeHusky explaining how I did it... It wasn't the best way to do it, but it worked and IMO, it was safe.

Here's the post on how I installed the spring

http://www.cafehusky.com/threads/rear-shock-spring.37103/#post-362349

I am positive that you can get a different/new/aftermarket spring in the UK.

Kyle,i've tried,I will be able to order a 250 spring and fit it,but there's no information really available as to spring weight etc,in the UK 125 are not popular,at an enduro where they might be 180 bikes only about 10 will be 150cc or less and at my local dealer I was the only buyer of a 125 through them in 12 months,so there's no interest in them and the main dealers sell bikes, they don't know anything about them.

One (or all) of these places will probably sell aftermarket springs:

http://www.shocktech.co.uk/
http://ftrsuspension.co.uk/
http://www.rg3offroaduk.com/
http://www.gforcesuspensionservices.co.uk/

I am also certain that you could call RaceTech, LTR, ZipTy, etc in ths US and have one shipped.

125 vs. 250 doesn't really matter that much, a shock is a shock for the most part.

Cheers Kyle,it's the sag I want to get right,I will look into them and see

Setting the right sag/preload was no problem. By definition, two springs with the same spring rates will compress the same amount over the same distance. So the length of the spring is irrelevent, so setting sag numbers isn't a problem.

However, the shock damping will be different between the two springs because of the position of the shock in the stroke is higher for the longer spring. So if that's your concern, then yeah - the longer spring might change some of the suspension characteristics (longer spring probably reduces the shock damping effect because the shock is 'softer' higher in the stroke). This is all theory.

As far as real life experience, personally, I haven't noticed a big difference in the shock performance since I swapped the Sach's 5.0 to the longer KYB Ti 5.5 springs.

spring*

You're over-estimating how long the spring is and how much pre-load is required to install the spring. It's only a few mm longer than it should be, so the spring only had to be compressed a few mm to install it. I had to compress the spring further to get the sag set correctly. If you look at the link I posted above, you'll see that my sag is good. I'm not the 1st person to do this and it's worked for other people too.

Your argument is correct if the spring is extremely long and needs to be compressed a large amount just to get it installed. But that isn't the case.

FYI, damping is effectively the same through the entire shock travel range. There are some position sensitive damping systems out there (KTM PDS I believe has a tapered needle of some sort), but standard shocks are not.

Ahh - good to know. I thought they all were position sensitive

http://www.k-tech.uk.com/rr_springs.php

Give them a call very helpful