125-200cc Shock Spring Question - MY2013 WR125

Howzit everyone!
I hope one of you can help...What is the “free length” of the OEM shock spring for the 2013 WR125? I don’t have a spring compressor tool for disassembly work, so your answer is greatly appreciated.

Mahalo nui,
PineapplePicker (Rey Angel)

Roger that. Thanks DirtDame!!!

I own the same bike and found a hand made notice in my owner manual saying 250 mm +/-1.5 mm.

...don't ask me were I get this information...

Further hand made notices:
Spring rate 5.0 kg/mm
100 mm race sag
12 bar / 175 PSI

jeanjean

I have the same bike (2012). I can confirm - no spring compressor tool required to remove the spring from the rear shock.

And if for any reason you still need the info, I have one on the shelf in my shop that I can measure.

You're right.
I remember using a spring compressor on old twin shocks but not on any monoshock I owned.

They have less preload, making it easier to remove the spring.

jeanjean

Thanks for responding jeanjean. The 250 mm dimension is the “installed length” (per the HVA Workshop Manual). I’m looking for the “free” length so I can have a reference point for preload with the OEM spring. It’s my OCD thing. I’m sure I need to get a heavier rate spring for my 185 lb carcass. Thanks again for responding!

Rey (PineapplePicker)

Thanks for responding Tetontimmy! I’m glad to learn I don’t have to buy a spring compressor to remove the spring. Those things are $$$. Is it a matter of just loosening the lock rings all the way out?

Thanks Zomby woof! If its not too much trouble, could you blow the dust off that beast and measure the free length for me? The real data is greatly appreciated, and will be added into my HVA workshop manual.

Rey (PineapplePIcker)

Is “12 bar / 175 psi” reference to Rider’s Weight?

Yes it is!

It's the pressure in the reservoir of the damper.


jeanjean

The OEM spring is fine for me with ~160 lbs.
So yes, you could try a heavier spring.

jeanjean

Ahh ok!

Mahalo nui, jeanjean!

I consider the pressure in the expansion chamber of the damper as it is meant, a means to avoid cavitation.
Usual pressure in our dampers is 145-175 PSI (10-12 bar).


Some people use it to fine-tune the spring characteristics, but I don't.
I prefer to keep it as it is.

If I remember correctly, the 175 PSI came from the German importer (it's not indicated in the repair manual).

jeanjean

I understand now, and appreciate the lesson and new (to me) information.

Yes just loosen the two lock rings all the way out, and push the spring up out of the way. That will give enough clearance to remove the slotted retaining cup under the spring.

Spring length is 260 mm
Spring ID is 61 mm

FWIW: The stock spring rate is 5.0 and at 145 lbs and soft setting the Racetech calculator said 5.6, which I used and found perfect. I had to go up on the rear and down on the front to .38

Thanks Zomby woof. I really appreciate your help!