OK I give up and I'm asking for help. I've got an 85 Trek 500 frame that I'm updating with a Shimano 600 Tricolor drive train off an 89 Trek 660. It's got braze-on downtube shifters and 600 Biopace cranks. My problem is finding the correct and workable path for the front derailleur control cable. Unlike earlier Treks where there were either cable guide braze-ons on top of the bottom bracket or a plastic cable guide shell that attached to the bottom of the bb shell, this model has guide channels in the shell itself and the rear cable runs through the seatstay. I can feed the cable around the bb shell through the groove but without any cable stop or cable guide on the front derailleur the only apparent pathway to the cable clamping bolt I can see us up through and opening between the derailleur body and the chain guides but when I install the cable on this pathway--just hand tight, thank you--no amount of pulling back will allow the cage to move toward the large chainring more than 1/8". Routing the cable to the outside of the shifter body causes it to lay over the top of the springs and then angle in to the clamping bolt. Am I too stupid to see something obvious here? The shift levers are complete and properly installed as is the front derailleur. Any help or advice would be much appreciated as I'm doing this build for my son in Colorado and can have it hauled out there Sunday morning if only I've got it ready to go and this is the only obstacle to completion.