This thread has piqued my interest! About 15 years ago, I picked up what appeared to be a NOS Schwinn World Sport at a resale shop for a ridiculously low price (IIRC $10)! It was Wintertime and they were clearing out non-seasonal items. The head badge put it at mid 1990 manufacture. Basic "fluff & buff" put this bike in like-new condition! Once the nicer weather rolled around, I took the bike out to fine tune my "fit" and do minor adjustments. It didn't take long to find out that this bike's handling was pretty "twitchy". I have a collection of bikes and this one is the only one that I cannot ride "no hands"! I don't ride that way all that often but do like to be able to do so if I want to stretch a bit or get a drink. It's probably the only reason that this bike isn't in my "ride rotation".
As mentioned at the start of this reply, this thread has rekindled my interest in this issue on this bike. I have often wondered if the original owner also had this problem and either relegated the bike to a dark corner of the garage or perhaps returned the bike to the LBS for exchange? I had considered some of the potential issues mentioned in the replies to this thread (bent fork or misaligned frame) but didn't really know how to confirm the problem. So with fresh eyes on the issue, I pulled the bike out of retirement for further investigation. No noticeable damage to the fork or frame was seen. I did do a 20 mile ride and confirmed my inability to ride without hands on the bar. Otherwise no issues. It does need new tires and I'd like to replace the saddle. Those aren't like causative factors but once that's taken care of, I'll start checking some of the specifics mentioned in this thread. Report to follow.
Sovende