I may try this again. I'm thinking that if a standard fork was swapped in, (the fact that the steer tube is cut a bit long is a clue) and the top race and cup is french, that might explain the slight knock/play.

I'm not going to attempt a beer-can shim because I don't want to die.

I swapped the bottom cup with one I had lying in my bag of assorted crap and I think I pulled that off okay. The bearing cages look pretty decent, but suspiciously modern, The top cup also looks somewhat chinese in its forgery, no patina on it. The headset is also completely different from the way-cool one on my Super Mirage, which is another clue. (sigh.)

ha! that might be from me! after i replaced the set from my grand record, i sent it to her. don't throw it away. maybe in another hundred years, it will have changed hands several more times and found itself on a moto back in france.

man, i hate headsets without wrench flats on the adjustable race.

What goes around comes around, eh?

so they say.

we could add that an indexed headset race isn't necessarily trashed. you could:

- toss the retainer and use loose balls, maybe adding a couple for good measure.
- smooth the race a bit with a file or sandpaper.
- even use a slightly different size bearing after using the paper. i haven't tried this approach, and it sounds like a lost cause, but it could work quite well (in theory).

i've seen a headset that used a ton of tiny balls that i assumed were slightly too small as compared to its original specs. but it worked perfectly.

if the lock nut or adjustable race is just ugly where it's been abused by vise-grips, a file and sadpaper might bring new life to it.

Here's what was put on it. The horror! I might try a BSA top section, in hopes that this might be an 80's Moto. What clues me in is the BB looks kinda japanese, so I might have a fighting chance. Thanks to the poster above who clued me in on the VO 41 MM issue. That was huge.

Was the PO a shadetree plumber by chance? Holy hot mess!

FYI: Loose Screws has a few French threaded headset bits (remember the listed prices get cut by 20% on checkout.) While supplies last, as they say:
https://www.loosescrews.com/index.cgi?d=single&c=Headset&sc=Top%20Nuts&tc=Campagnolo&item_id=CA-7161020
https://www.loosescrews.com/index.cgi?d=single&c=Headset&sc=Top%20Nuts&tc=Campagnolo&item_id=CA-7161074
https://www.loosescrews.com/index.cgi..._id=CA-7161074
https://www.loosescrews.com/index.cgi?d=single&c=Headset&sc=Top%20Nuts&tc=Campagnolo&item_id=CA-7161134
https://www.loosescrews.com/index.cgi?d=single&c=Headset&sc=Top%20Nuts&tc=Shimano&item_id=SH-7139802
https://www.loosescrews.com/index.cgi?d=single&c=Headset&sc=Keyed%20Washer&tc=&item_id=SH-7191310

Update: Ingeniously, I swapped the top section off of...get this.... a Taiwanese Peugeot kid's bike. And I think it'll work. So I must have an 80's moto. The Tange fork, BTW is a Tange 3C, if that helps anyone out there.

I need to get calipers to measure stuff. Right now it's all trial and error and intuition.

Hey thanks to all for the help. have a safe and happy holidays!!!!

..... about two or three bucks at Harbor Freight, more than adequate for bike uses.

oh cool I'm there!

French steerers are 25mm with 1mm pitch threads. British/ISO/Japanese steerers are 25.4mm diameter with 24 Threads Per Inch pitch threads.

If you try to re-thread a 25mm steerer, not only are the threads going to be undersize but the pitch will be off:

24 TPI = .0416 pitch = 1.058mm pitch.

1mm threads = .0394 pitch.

After about 4 or 5 turns the adjustable top race will reach a point of interference. A ham fisted, hammer mechanic can force it but the headset will always come loose from use.

There is nothing magic about metric threads. The whole world except for 3 countries, the US, the African nation of Liberia, and Myanmar (formerly Burma) use metric standard threads.

The Japanese bicycle industry adopted British Standard Bicycle Threads a long time ago. Because of the influence of Japanese bike makers (now Taiwan and China) the ISO (International Standards Organization) adopted British threads for bicycle headsets, bottom brackets and freewheel threads.

There are a number of PROPERLY functioning solutions for replacing the headset in your Motobecane Mirage. The first obstacle is finding a headset with a usable stack height.

You need to measure your fork and frame to determine the stack height capacity:



Most European lower priced bikes used headset with a stack height of ~30mm to 33mm. VeloORANGE headsets have a 41mm stack height which is too high for all but the top pro model frames.



A quick search on eBay for "French Headset" came up with 84 items. Mike Fraysse always has these replacement French headsets for $24.99 USD:

Vintage Stronglight French 25x1 Peugeot Motobecane Bicycle Headset | eBay

Most French headsets had 27mm fork crown races whereas most inch size headsets (British/Japanese/ISO/Italian, etc.) had 26.4mm or 26.5mm crown races. 27mm fork crowns need to be cut down to use a crown 26.4mm crown race.

There is another alternative to replacing the whole headset. The fork crown race and lower headset cup are usually the only parts that wear out. Get one of the following Tange headsets and only use the bottom parts which have a classic look:

You can get a Tange Passage inch size headset with a 27mm crown race for under $20.00 USD. They have a 30mm stack height and can be found with a 27mm crown race:



The Tange Levin CDS headsets have a 33mm stack height and are also available with 27mm crown races. They're very good quality for the money - $15.00-$30.00 USD plus they have precision ground through hardened races and a plastic dust seal.



BTW, Tange made metric threaded forks both as replacements and OEM forks for French bike makers.

Easy fixes to simple problems...

verktyg

Very good info. Thanks.