My son just bought a used downhill bike. 2014 Devinci Wilson. The front forks are Fox 40 coil, not air. He has ridden it around a bit and it seems the front forks are WAY too stiff. We try to make adjustments but nothing seems to change. Will these need to be rebuilt? Do they even still sell rebuild kits for such an old fork? Or will a servicing fix the problem?
Have you checked what spring is in there? If it´s a coil sprung fork you obviously have to put in the correct spring weight to match your sons´s body weight. I presume he´s not very heavy and maybe the previous owner put in a heavier spring. Service is never a bad idea, especially for a used fork, but it has nothing to do with the fork being too stiff. Unless of course, the fork is full of sand No need for a rebuild kit. Just get the required oil and some replacement seals and you´re good to go. It seems though like you don´t have much experience with this kind of stuff, so it may be better you just send the fork to a reputable service center and let them give it some love. They can also change the shim setup while they´re at it if your son requires a lighter tune.