So I don't weigh that much and I bought my 04 from my uncle who weighs much more than me and I'd like to adjust the suspension but I have no idea how it works and i can't fins any great info online
Looks like its exactly what I need because i weight about 145-150Im trying to adjust my stock shocks too but i found this. The link to the forum i found this washttps://www.yfzcentral.com/threads/adjusting-stock-shock.58536/
I didn't write this.
All right, we have been adjusting the 450 many ways and have found a MAJOR improvement for jumping, and here are the settings for anyone interested.
The 450 is set up for a 170 pound person, and if you are LIGHTER than this you are going to be amazed at the improvement you are going to get jumping, you will be able to at least double your height with these settings.
The dog riders have released their secrets to me so I have to spill the beans.
On the front shocks on the 450 at the BOTTOM of the shock there is a golden screw. take a screwdriver and turn it counterclockwise until it stops.
This is the rebound screw. When you loosen the rebound (all the way counterclockwise, the shock SEEMS SOFTER and it RETURNS FASTER, and it makes it feel like a softer shock, softer ride, though it is actually adjusting rebound speed.
The best setting for 130 pound person is all the way out counter clockwise then turn it clockwise until you hear 5 clicks.
DO THIS FOR THE OTHER FRONT SHOCK ALSO.
Ok, now the golden screw on the top of the shocks needs to be turned all the way counterclockwise till it stops and then turn it clockwise 9 clicks.
Now at the top of the shock, there is a metal adjustable ring that screws up and down on the shocks, this sets the stiffness. if you are 170 pounds or above, leave it alone.
if you are, however UNDER 150 pounds, then THIS IS YOUR LUCKY DAY!
You will be able to FLY!
Turn those rings out until they can't go up any more, (you will see it lengthen the springs as you turn them. give it at least two threads from the top so you don't strip it. and then turn the other one up too to lock it in place.
With these adjustments for jumping like above if FEELS 80 percent better.
If you could jump one foot with stock setting, you can now jump 4 feet and it feels about 50 percent BETTER!
Now the back shocks.,
The two big screw rings (one is a lock ring) loosen all the way, except for two threads so you don't strip it. (this takes the preload down to minimum for jumping. You have to take the four screws out of the air box that mounts to the frame, and loosen the hose clamp that holds the air box hose to the carburetor. DO NOT TAKE THE HOSE OFF THE AIR BOX IT IS HARD TO PUT ON AGAIN! Now you can adjust the rings.
Now for the back shock, take off the seat and you see the shock. There is a gold screw there, that is the compression screw. Screw it all the way IN till it stops (CLOCKWISE!) then do two complete turns counterclockwise and 3/4 more for a total 2 and 3/4 out on the screw.
Now put the seat back on.
Now go on the right side of the quad and look under it at the shock bottom linkage mounts.
You see a golden screw right above the bolt that holds the bottom of the shock.
Screw it COUNTERCLOCKWISE (all the way OUT) and then screw it back in 1/2 turn only.
The front shocks when adjusted should be adjusted similarly with the back or else whoops feel bad. always make the preload (THE BIG SILVER SCREWS RINGS on the shock tops holding the springs) similar in front and back.
This was very helpful IMO.