Folks -

I have an 08 Dakar Expert. 19' frame. On my last two off road rides I noticed a "knocking" sound coming from the suspension area. I tightened all the bolts and rode it again in an enduro race and it continued to "knock" the whole time. It "knocked" even when not accelerating. I took it to my LBS and the mechanic tightened all of the pivots, bolts and BB. I rode it in the parking lot with no "knocking." Of course this is a parking lot and not trail conditions. When I first test rode the bike it never knocked and the first ride was on the road just so I could dial some items in. It never "knocked" then. It is very deep in sound so I think it is metal on metal. Could it be bad threads, cracked frame? Has anybody else similar issues?