My buddy just bought a nice '98 250 MXC. He weighs about 180 or 185 and the bike with him or me (at 165#) on it wallows a lot in the sand and the back end likes to swap on rough downhills. My question is about the rear shock spring, it is a black Eibach spring. Is this the stock spring? I was wondering if maybe the guy he bought it from had the suspension setup for him, and maybe he was a bit heavier. My buddy bought the bike off of Ebay and got it at the owners buddys house and never actually met the owner.