Suspension & chassis set up CRF450R

[jeffmort]

I am trying to properly set up the suspension on my 2009 CRF450R. I am 5' 11", weight is 198 lbs. (with riding gear), and I am a novice level Vet rider. I ride MX tracks only in Southern California. I do not race - just a weekend warrior.
For the rear suspension, the closest I could get to proper set up with the stock spring is 97mm for RACE SAG and 40mm for FREE SAG. My manual calls for a range of 95-115mm for Race Sag - I am in spec for this.
The manual calls for 10-25mm of Free Sag - I am out of spec for this.
I have tried to adjust the spring pre-load to get within spec for the Free Sag but when I get within spec for Free Sag I end up out of spec for Race Sag.
The manual says that the stock springs are for a rider in the 165 lb range (I do not know if this is with or without gear - the manual does not specify). My bike feels pretty good as is but I do not have a reference point to compare to.
Based on what the manual says and the measurements that I got, I believe that I need a heavier rear spring - is this the correct conclusion?
Any help is appreciated.

 

[IndyMX]

Yep, you sure do need a heavier rear spring.. And more than likely heavier front springs also.

 

[jeffmort]

Thanks.
One other question regarding the relationship between Race Sag and Free Sag:
As I adjust the rear to decrease the Race Sag (lessen the Race Sag measurement) by increasing the shock/spring pre-load (tightening the pre-load nut) should the Free Sag # also decrease?
If this is true, then the opposite should also be true (i.e. if I increase my Race Sag by decreasing the pre-load (loosening the nut) my Free Sag measurement should increase.
This is what seems to be happening when I make my adjustments - is this correct?

 

[IndyMX]

Sounds correct to me..

 

[jeffmort]

Thanks.

 

[kawamaha]

a free sag of 40mm indicates the spring is too stiff for you.
on the other side you have an average weight and I think your in the ballpark for the stock spring.
the 09CRF is supposed to be too high in the rear, so you may try 110mm of race sag?
for what honda recommends, it seems they didn't change their numbers over the years, now a free sag of 25-35mm is standard

 

[jeffmort]

Kawamaha-
When you say "a free sag of 40mm indicates the spring is too stiff for you" - this is what I have read elsewhere as well but my Honda owners manual actually says the opposite and my common sense (for what is worth) agrees with the manual. The other factor that makes me agree with the manual is that it says that the stock spring is for a 165 lb rider and I am at 198 lb with gear which would point to a stiffer spring needed.
The other confusing point is that when I increase my Race sag # by decreasing the spring pre-load, my Free Sag # has been increasing as well - in other words my Free Sag # is moving the same direction as my Race sag 3 whether I am going up or down.
The point you bring up is exactly why I started this thread - because things just are not adding up.
Eventually i will figure this out.

 

[jeffmort]

After talking with the tech guys at MX Tech, Factory Connection, Pro Circuit, Pro Prept, and a few other trusted sources, here is what I found:
1) If Free Sag number is too low, then a heavier spring is needed. If Free Sag number is too high then a softer spring is needed. (The Honda manual says the opposite but my conclusion is that the manual is wrong and has a mis-print).
2) The conclusion of just about everyone I spoke with was that the stock rear spring is fine as is (for my application). If anything I would need a slightly softer rear spring.
3) Stock fork springs are fine as is (for my application). If anything I would need slightly stiffer fork springs.
4) A longer linkage arm is definitely helpful.

Thanks for your input.

 

[kawamaha]

now that you agree with me and some others ;)
I explain that sag thing:

you adjust your race sag to 100mm and get a free sag of 40mm - means the bike sags another 60mm due to your weight.

lets assume you try another shock spring, adjust it to 100mm race sag and get a free sag of 20mm - means the bike sags another 80mm due to your weight.

which spring is stiffer, that one that let the bike sit 60mm or that with 80mm ???

hope this helps to understand that a little better :ride: