Bianchi Headset Issue?
 

I picked up a 1983 Bianchi Sport SS for $200. All original components. Manufactured in Japan. Good deal?

Anyway, I have been going through and servicing all the bearings. The headset seems like it's notched in the forward position. That is, it feels like it wants to stay in the forward position and once it's moved its fine. Is this normal? Was this a built in design feature?

Pics for attention
https://lh3.googleusercontent.com/_V...m_OD1B=s803-no
https://lh3.googleusercontent.com/IH...3lkqQU=s803-no

Two possibilities...

The headset is too tight or the bearing races are indexed, or dented, forcing the balls to fall back into the dents.

Were it me, I would disassemble the headset and look for the indexed or dented bearing race. If all is good, assemble and adjust to eliminate slack and prevent binding. If the headset is indexed, replace it. There are tricks to avoid replacement but don't recommend them.

No, it's not normal. The races have become indented where the bearings sit. There are conflicting theories on the cause. One attributes it to loose adjustment and the impact of the balls causing indents in the races. This is commonly called brinelling. The other theory contends that a breakdown in the lubrication causes the balls to weld to the race, resulting in minute portions of the race being pulled away and causing indents when there is steering movement. This failure mode is called fretting.

Regardless of the cause, there is a workaround that does not require a new headset. Replace the caged bearings with loose bearings. This increases the number of balls, preventing them from aligning with the indents in the races.

Is the indexing something that could have been done from the factory? Is there any harm in riding it that way?

No, the factory would not do that. As for harm, you will make the notchiness worse if you do not fix it.

Thanks, I just bought a Velo Orange headset to replace it.

If you buy a headset, there are a few measurements you'll need to know. It's a 1" threaded headset, but there were multiple 1" headset standards. Being a Japanese bike, it might be sized to Japanese Industrial Standard (JIS) instead of the ISO headset sizing you'd find on an Italian-built Bianchi.

If you have a caliper, you can measure to determine which you have:
* Is the fork's crown race seat 26.4 mm (ISO) or 27.0 mm (JIS)?
* Are the cups 30.0 mm (JIS) or 30.2 mm (ISO)?

...and to make things a little more confusing, there are at least a few bikes out there that actually have mixed headsets. The crown race might be ISO and the cups JIS, or vice versa.

Velo Orange sells both JIS and ISO sized headsets.

Fretting is a result of riding with headset loose, so the balls had some acceleration space..

Its not a expensive part, you can now replace it.

Jobst Brandt disagrees. I simply wanted to present both theories on this failure mode.