Originally Posted by Eastbay Dirtbag
I don't know about in 2013, but in 2014 the Boise NF's MVUM maps for the Emmett and Cascade districts are consistent and show that West Mountain Trail is NON-MOTORIZED NORTH of the JUNCTION with Joe's Creek Trail #137. The sign on the ground is also consistent.
West Mountain Trail (#131) from the South Trailhead off FS 626 and Joe's Creek Trail (#137) from its trailhead off FS 394 are both Motorized to their intersection but not beyond. So you cannot legally ride to Tripod Peak or Snowbank Mtn.
Here is the sign heading north on West Mtn Trail at Joe's Creek junction. Photo taken 9/29/14.
Thanks for the PSA. Glad you didn't attack OP for his decision to ride that trail.