1986 Fat Chance

If the cable guides drag get a section of the plastic insert from the inside of normal gear cable and run the cable through it under the guide, frees the cable up loads and reduces the drag a huge amount (and it's a cheap fix as well - use it on my bike with similar problems)

Forgot to say, it the biopace feels odd take the rings off and turn them through 90 degrees and put them back on. It makes the 'deadspot' reducing ring shape work in the right way rather than shimanos dodgy way, still feels a little odd compared to round rings but it actually works tons better