Rejuvenating my 1990 3cv

[Urx]

There is quite a lot to do to reverse the long slow slide that set in on my FJ.
It was my first nearly new bike (after a few fun but disastrous months with a Ducati Pantah...the 500s have weak gearboxes)
Anyway feb 1991 i bought my FJ1200 3cv in midnight blue with gold accents.
It was several weeks before i discovered that what looked black in the winter gloom was actually a deep metallic blue.
I dont recall the mileage when bought but it wasnt much.... acouple of thou max.
Anyway....30 plus years later and with 32k on the clock...its time for all the the wrinkles that develop over time to be sorted.
Scope of the project is mainly cosmetic as time has taken its toll on paint plastic and alloy.
Suspension is up for improvement too
Engine seems all good.
Ive started on the work and will try to record what i find and do in case it helps anyone else thinking along these lines.

[Urx]

So my xmas present has been un wrapped and its some slab yokes to add an R1 front end to my FJ
https://fjowners.com/gallery/12/7199_08_01_23_1_39_29.jpeg


Feel the shiny 8-)

Takes std ignition switch, lock stops are included and so are handlebar clamps to accept the Jota bars i aquired
I should be ablr to get back pretty close to the desired position and angle etc

[gdfj12]

Urx, if you don't mind revealing your source, where did you get those beautiful triple clamps an stem?

George De

[Urx]

A very nice and knowledgeable chap called Roy Martin who runs BilletBikeBits. If you google they will appear.
Essentially they specialise in custom slab yoke machining but can make pretty much anything and its done to a very high standard of finish.
I am very happy with mine and the RPM-like level of service.

Next photo set will be the carbon fibre mudguard and the R1 forks loosely assembled with the foxeye FZR front wheel.
I'll need to work out the wheel spacing for the spindle but it should all slot together nicely.
The 5pw 2002/2003 model R1 is the last to have the old style axial calipers and have a spindle size that is compatible with the late FZR front wheel. I can use the FZR speedo drive to retain my FJ clocks too.
Happily there are various spring rates available easily and the forks have preload compression and rebound adjustment.

i was swithering on a brand new set of 2022 forks at a very attractive price but id then need calipers and more futtering to make the spindle work.i may just go for it anyway as they are really nice.
End up with a front end worth more than the rest of the bike but who really cares if you arent going to sell it on.

[Pat Conlon]

Great to see this project, thanks for the updates, keep 'em coming!
Q: What's your plan on making the R-1 fork legs longer? IIRC the stock R-1 legs are too short for our FJ's.

Cheers

Pat

[Urx]

Ahah....these yokes are cunningly designed to allow approx 2" of adjustment of height/length....'thug yokes' is the name.
You drop the forks down till you get the ride height/steering angle you want and there are blanking discs included so you get a nice smooth top yoke...
The upside downies tend not to compress as much as 'right way uppies' so i should be able to get whats wanted.
Worst case there is a company in England that will make replica stanchions upto 3" over length.
Resell the std ones as they are fine...jobs a good un.

[Pat Conlon]

....The upside downies tend not to compress as much as 'right way uppies' so i should be able to get whats wanted.

On my YZF750 USD's I changed my 1.05 kg/mm fork springs down to 0.95 kg/mm and now I'm getting a very nice 2.5" compression with my rider sag set at 1.0"



Proven fact: USD forks gets the chicks....

[Urx]

I like the polished finish on your outer tubes!!
Looking veeeeery nice there...mine are std black ....at the moment...i might be persuaded as shiny looks nice but the damp weather here isn't kind to unprotected alloy...

[Millietant]

I'm using 0.95 springs in my FZR USD forks too 

Would love to keep them all polished up like Pat's, but not living in an "Arid Zone" and riding on a small island, surrounded by salty sea air, it would take just too much of my time to keep them like that ! 

[Urx]

Well i finally got round to test fitting my new yokes to the FJ
Forks place and wheel all test fitted
There are titanium fastners for the discs forks etc so corrosion shouldn't be an issue.
Disc spacing isnt quite right though.
Test assembly using the std R1 yokes had everything lining up....not now.
Discs will need to move inboard by about 10mm i think for the calipers to line up.
Ill start re measuring everything tomorrow

[Old Rider]

I dont know the offset on the rotors but maybe it is possible to turn them inside out ?? or mill down the wheel hub

[Pat Conlon]

Disc spacing isnt quite right though.....
Discs will need to move inboard by about 10mm i think for the calipers to line up.

You can buy aftermarket rotors (disks) in different  1) offsets 2) inner/outer diameters 3) bolt patterns.
Figure out your needed (total) offset and look up the rotor you need.

If you only needed a 2-4mm adjustment you could mill or shim the caliper or caliper mounting points according, however 10mm is too much material to remove or shim...

How to measure: https://www.metalgear.com.au/blog/support/how-to-measure-a-brake-rotor/

I looked at my saved link for the motorcycle rotor cross reference catalog based on size and offset...but link no good.

Do other folks have a link for a cross reference?

[Urx]

I reckon flipping the discs will get me close...i'll get measuring and see what needs to be done.
The wheel is probably the cheapest most expendable item so if anything is going to be machined it'll be that

[Pat Conlon]

Cool, keep us updated on what you do....

[Urx]

Well after putting everything in place it looks like 2mm each side is the size of the mismatch.
The front wheel is a 95 fzr1000 with std oem fj discs and the calipers are gold spot r1 5pw on std r1 forks.
The youkes are billet custom.

This lot when centered between the calipers has the discs just touching the outside edge of the slot through the calliper
If the discs moved inboard 2mm each side the alignment would be perfectly centred
I can get a machine shop to either
take 2mm off each side of the wheel to narrow the disc mounting faces
Take 2mm off the joint side of where each caliper mounts to the forks
Take a slot drill through the calliper and enlarge the slot by 2mm on the outboard side of the caliper
Get discs with slightly less offset

Thoughts?