This one is also known as Trail 99, and is part of the Humbug OHV area in Klamath National Forest.
The trail branches off from 55098 (Trail 98) and quickly descends to Siskiyou Rd 7J001. The trail starts level and turns into a very fast descent with optional jumps. The trail surface is sandy compact soil. The vegetation is mostly manzanita. The small scrub doesn't offer much in the way of shade, so bring plenty of water.
The Humbug OHV area has a network of trails designed for ATV and dirt bike use but is open to the adventurous mountain biker. Be aware of other trail users, as they may not be looking for bikes - keep your ears open.