Ultegra 6700 10-speed shift cable frayed at the lever end. I got the lead head end out far enough to cut it off, then pulled the cable out from the other end. There were several 1/2" bits of cable left at the head end, which I removed. When I try to install the new Shimano cable, there is a lot of resistance, causing me to think there may be more bits of cable stuck in the routing path. Any suggestions on how to proceed? I tried inserting the cable from the other end, but it doesn't follow the routing path and comes out the front of the shifter. Thanks.