Corsa Chain Adjustment.

851corsa

This ebay decal says 25-27mm but I have seen ones that say 20-25 and 25-30, all claim to be for the 851/888.

What does an original, factory fitted from new, 851 decal say?

I ask as the race bikes did not have any such sticker affixed to them at all.

Also:

The part number 24 in these diagrams:
How tight should it be and exactly when in the Chain adjusting/ Wheel removing/ Tyre changing process should it be tightened fully.

The axle nuts I am doing at 55 ft/lbs.
The Adjuster bolts at 7 ft/lbs.

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Utube: 851 Superbike racing '91

BABA

I don't know exactly, I saw this 25-27 adujsment on the '92 strada of a friend last WE... I never pay attention before.
25 mm is the common value for the 3 stickers... so 25 mm will be good😁

[edit : I have just verified on a pic, on my 94 strada it's just mentioned 30mm]

For the special screw, I don't think you have to remove it when you adjust your chain or when you change your tire.
It is used to maintain caliper in position with the swingarm, to change faster the rear wheel.
... In fact, I don't verified it yet... I'm still in theoric mounting😉

BABA

More details...

851corsa

BABA,

Again, thanks,

I will be following these instructions,
http://www.ducatisuite.com/chain.html
http://www.ducatisuite.com/chainlube.html

I suspect the number 24 bolt should be fully tightened on initial assembly, but will hold off till I know. No rush!
Don't really want to bug John Hackett...

Would still like to know for sure how many mm an original, factory fitted from new, 851 decal says though.

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851 Superbike racing '91

BABA

Right adjuster stays tight to keep the position during the change with caliper in place. Left adjuster free to remove the chain and the rear wheel axle.
I have found these pictures... and I will ask to a friend if I can post a better picture which shows what I describe above.

BABA

Rear wheel changing on a Racing 92.
Picture from that period.

851corsa

851 swing arm with its original decal.

Thanks for the confirmation.

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Utube: 851 Superbike racing '91

scott 888

926, Supermono rear brake bracket

Slightly off topic sorry Baba but relevant all the same I have the very last rear brake caliper bracket I have for sale at £50 plus postage just requires very light rubbing down and then anodised black for that factory finnish.

Pm me please first come first served, thanks.

Scott

guy851

Swinging arm corsa adjusters and spacers

Baba you have some very nice sliders and spacers there

All we need is a kind Frenchman to ask the cost from a local CNC shop to make some more sets and share them on the forum 😁

Nice work and nice detailed pictures

Guy851

BABA

Thanks😄
But all of this couldn't be made without Phil911's help... 😎

Terry,
I have checked in the 851 89-90-91 workshop manual. They mention 15-20 mm machine on ground and rider on seat.
20-25, 25-27, or 25-30 mm is for bike on side stand.
It miss the page in the SP workshop manual I have. So I cannot verify for them (in theory, it would be the same).
I check pics, SP3 and SP4 have the big MICHELIN sticker as Racing, so they didn't have the adjustment sticker.
But SP4 owner's manual mentions the 25-27 bike on side stand (as the '92 strada of a friend have on his swing arm).

Torques are in the parts catalog if you have it.
Rear wheels : 78,4 - 83,3 N.m (So 57,8 to 61,4 ft.lb)
Adjuster... not mentioned, but by hand is good 😄

phl851

Excellent pictures, great detail.
What is retaining the carbon hanger, is it a regular circlip that fits in the groove ?

BABA

Yes, it's an external circlip.
You can see it on assembly pictures

851corsa

It was quite straightforward, things often are when you can physically handle them and see how they interrelate.

Exactly as you suggested in post 2, Part 24 secures the brake calliper hanger but plays no part in the wheel - chain assembly.

All the elements are aluminium so gently does it.

Image is from JHP.

Too important to assume so had to be sure.

Thanks for the effort you put in BABA/Phil911.

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Utube: 851 Superbike racing '91

BABA

In reality, the reducing spacer is in aluminium and the special screw in steel.

I made the screw in aluminium because aluminium is enough strength (this is not a structural component) and easier to machined.
Also lighter even if the difference is tiny😉. I also prefer this material for its best aspect. Even if the anodization was not very successful for this part.
It is part of the first components we try to anodize with my father, but we didn't know that aluminium alloy with copper (like the 2017 alloy) becomes black after its soda bath and that it needs another soaking in nitric acid, just before the electrolytic solution soaking.
Other series were better after that (except for black colour, it didn't work...).

851corsa

Yes that is correct, the original screw is steel.

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Utube: 851 Superbike racing '91

surfking

Axle sleeve for rear brakeHanger

I'd mis placed this, but it looks different to the ones I've seen dose anyone know if it's the same but different.

Nick

Jasper

Mine doesn't have the circlip or the bush.

eric

And mine with missing parts.