Correct springs for a 250 lb rider 2004 Yamaha WR450F
Posted October 12, 2004 - 10:06 AM
Posted October 12, 2004 - 11:52 AM
Posted October 12, 2004 - 01:17 PM
Posted October 12, 2004 - 07:06 PM
Posted October 13, 2004 - 01:56 PM
Posted October 13, 2004 - 07:22 PM
i.e. doing a simple ratio
-- = --
determines that all of us fat boys need a 7.9 kg spring
Posted October 14, 2004 - 12:31 PM
Posted October 14, 2004 - 05:14 PM
Posted October 14, 2004 - 05:17 PM
Posted October 14, 2004 - 05:41 PM
I can't expalin the discrepancy between what RT (and other tuners) recommends and what actually worked for me.
My neighbor (same weight as me) on an 03 WR450 runs a 6.0 spring and has zero free sag with 100 mm of race sag.
Check this thread out from the Suspension thread:
Shockdoc is a tuner and a regular contributor to that section.
Posted October 14, 2004 - 09:55 PM
Posted October 14, 2004 - 10:11 PM
Here is our plan. We are going to swap springs with a guy who bought a used WR400 that is way over sprung for his weight. We had his springs tested today and they are .49 kg/mm front springs and 6.0 kg/mm rear shock springs. This guy is in the 160 lb range ready to ride----- so, he will be very happy with the stock springs from my son's 2004 WR450. The .49 kg/mm front springs are as stiff as you can buy and the 6.0 kg/mm rear spring is much closer to being the correct spring than the stock 5.2.kg/mm spring. I want to believe that this is going to work. If it doesn't work then all I can say is, "We were going to have to buy new springs anyway, because staying with the stock springs was not an option".
I'd say your setup will work fine for your son... but I just wanted to let you know .49 isn't the stiffest fork springs you can buy... MX-Tech has WR fork springs up to .52