250-500cc Fork issues...

So I posted this in another thread but I am trying to get it figured out asap incase I need to order parts. This is what I have going on...

So I've had my bike for a couple weeks and have been on a few good rides. the front end has been all over the place (esp in the rocks) almost wiped out a couple of times. Figured it was time to get this all tuned in and wow I am WAY out esp on the front!!

So the guy I bought the bike from did MX with it it came with a extra pair of springs and on the paper it says .48. here are my numbers

Front 300mm travel
0 static
32mm rider !!!

Rear 305 travel
48mm static
93mm rider

My front is off the charts! Looks like I need a WAY lighter spring maybe he has the .48's in there??... no idea! The rear looks like a step heaver spring? maybe for now just mess with the preload to get my 104mm rider? I need help LOL

UPDATE: So I pulled the springs and the "48's" don't even fit the bike they are a hair to wide and much longer lol... The springs in there just slide down no issues so they must be for a different bike? Always fun figuring out other peoples "tweaks"

Is there a preload spacer in the fork with the springs that are in there right now? It's hard to tell how bad (or not bad) the situation is since you have zero static sag.

If there is a preload spacer in there, go ahead and cut 35mm off of it and then re-measure. It's possible that the spring rates aren't as bad as you think and the preload is the problem.

Rear spring looks too soft but I would get the front in the ballpark and measure it again.

I am looking at the parts diagram where would the preload spacer be? Would it be between the spring and the top cap? Thanks for the input really appreaciated!

Either on the top or the bottom of the spring. It'll be a metal or plastic tube, often people use PVC pipe, that is roughly the same size as the spring.

You can also just estimate how much preload is in the spring. When you go to put the top cap back on, how much do you need to squeeze the spring back down in order to get it to thread on?

State what bike/fork you are working on, it really matters. 45mm Marzocchi's all have a spacer under the spring or the spring will trash the cartridge.....Also always bleed the air pressure in your fork to atmosphere with the wheel off the ground before getting started. Forks have so much seal surface area and therefore stiction that basing decisions SOLELY on rider and static sag is IMO not the way to go. I like KT's comment on spring preload, I'd be looking for about 15mm.

Hey thanks guy's, The bike is a 2011 WR300 KYB OC 48mm forks. I will check to see if there is a spacer in the bottom when I get home as i am going to go ahead and change out the fluid anyway (don't think this will do anything for sag tho?). Think I will use 5w fork oil at about 110mm this sound about right for colorado trail riding? Going riding tomorrow so hoping to find something tonight or I will just deal with it tomorrow. If I don't find a spacer in the bottom I will measure how much the spring sticks out and report back. I did do some searching on Kx's and other bikes but am having a hard time finding info. Maybe I just suck at searching the web lol.

Sooo... I am not sure what happened but I pulled the forks changed the fluid with 5w to 120mm didn't see any spacers so I put back together... Re-Checked and I am at 30 static and 55 rider sag??? I don't think the fluid had anything to do with it. I think something was tweaked with the front axle/forks maybe? WOuld that do it? I swear i'm not crazy lol... well maybe haha a little but it's totally different than it was.

Mis-aligned forkleg on the front axle, or air-build-up could cause it. It's normal to have no spacers on the KYB's.