If it were me I would buy a service manual, dismantle and check the linkage, swingarm, shock, axles and steering stem bearings. Know telling when this was done last. Then if every thing checks out ok I would lube them with some high quality grease. Lube your cables and chain and sprockets, clean air filter and re-oil, install new plug and ride to your hearts content. By then you'll know if theres anything else that needs attention after you have some time on it. Enjoy! Also read all you can on this web site for tips on getting your KDX set-up and runnig at its best.