GENTS,
I took off the rear wheel of my Sport project bike, and found the inside of the swingarm all buggered up from loose sprocket bolts. 2 of the bolts were sheered, one was just gone, and one of them was still floating around in there beating up the swing arm. The other 3 were all loose, and bent. The chain adjuster does not move. I'm not sure the swingarm is salvageable.

This bike has a modified SS swingarm from a 750 (steel swing arm), so this has happened before to this bike.

Three things,

1. Anyone got a spare Sport swingarm they would like to sell? Any condition. I can get it welded up no problem.

2. Anyone have a good method of retrofitting another swingarm onto the Sport? (Swingarm pivot pin sizes changed, as did the width of the cases. But the shock mount and other dimension are same as SS) Both of my bikes have SS swingarms on them, one steel, and the other aluminum. Both took considerable work to get them to work, and I'm not terribly happy with either solution so far, so if there is an easier/better solution, I'm interested.

3. If you are still running the 16" wheels:
- Run the bolts from inside the carrier with the nuts on the sprocket so that if they do come loose, they don't foul the swing arm.
- Check that your bolts are always tight. Something in this design lets them work free. These were all grade 8 bolts, with loctite, and nylock nuts.

Oh, and I can confirm, the Sport has a 17mm axle, while the Paso has a 20mm axle. This rear wheel has a shim tube inside the bearings to fit the smaller axle.


Cheers, Phil

Hi Phil,

Sorry to hear this.

Maybe this will help:



I do not know the price.

Good luck

Joep

Joep,
Thanks,
Well, he certainly has some very cool parts, but there are no prices on anything. The only way, as best I can tell, to get a price is to send him an e-mail and ask him. I am afraid that this might be the case that "if you have to ask the price, you can't afford it"

He has a very cool steel tube swing arm that would be pretty cool. I sent an e-mail.

Cheers,
Phil

Websearch result kinda infers that the F1 and TT1/TT2 swingarms seem to be the same mounting as the Sport. The key numbers. 28mm pivot axle/pin, and 155mm wide cases. Ill measure the SS parts for comparison.

Here is an interesting site that has some nice swingarms.
http://www.redfox-grinta.com/?page_id=263

Anyone ever try an F1 or TT1/TT2 swingarm?
How about this beauty?
http://www.twowheelclassics.co.uk/catal ... ngarm.html

Edit:
Another interesting string. Seems the F1 - TT1/TT2 boys are poaching the Sport swing arms to fit their bikes to run fatter rear tires, or just replace them. Mounts right up, but there are a few different shock attachment points it seems.
http://www.ducatittandf1.com/viewtopic. ... arm#p17696

Also seems that there were a few different 750 Sport swingarms over time with different axle types.

by the way, what is the bearing arrangement on Sport swing arm? I haven't pulled the pin yet, and the manual doesn't offer much insight.

Cheers, Phil

Phil,

What do you mean? I see seals and needle bearings in the engine block.

Do you need their sizes?

Kind regards

Joep

Joep,
thanks, thats one data point. From 1991 on, all Ducatis had two needlebearing in each side with a seal. Some of the pictures I have seen posted of the Sport infer that there is no bearing, but a dimpled bushing. The Paso had something different again which i don't quite understand yet.

Edit/Update.
I pulled the pivot pin, and indeed there are bushings in the cases, not needle bearing. Fortunately, I have a brand new pivot pin, and the fit seems to be proper without free play, so I will leave the bushings in place, but replace the seals.


Cheers, Phil

Phil,
I was just reading in "Belt drive two valve twins" that ducati made 3 oversize pivots for the early 500 Pantahs because of bush wear.Not sure if that was still the case with later models.Maybe there's something in here to help.https://www.box.com/shared/nzfez3vs4q

Cheers
Andrew

Thanks for the link. Makes for some great reading. Some of the things that we have found on the list so far, like gas tanks leaking from cracks, and swingarms cracking. No specific mention of the swingarm bearings, but does show that its simpler than the Paso.
I'll live with what I got for now. New seals and shims on order, and I have a plan to straighten out the mangled box section on the swingarm to get the adjusters to slide once again. Some fresh paint, and it should be good to go.

But I did notice from this writing that there was an updated swingarm and that it was covered by warranty. Has anyone gotten a new swingarm on warranty? Can anyone identify what the updated version was?

It also infers that this was a problem with the F1 series, and that group is poaching Sport swingarms because they are stronger, and fit larger tires. So my thought of finding and fitting an F1 swingarm has been put to rest.

Cheers, Phil

I'm guessing you mean the later model F1 swingarms like this one.



The only problem is there were'nt many F1's made so the swingarms off a wreck would be few and far between.
I would imagine this bloke was sick and tired of cracked swingarms by the looks of it.


Cheers
Andrew

The Belt Drive Twins Restoration Manual stated that many Sports had early swing arm cracking issues and were replaced by warranty. Seeing as to how I have two sports without stock swing arms, I can agree with that. But the manual also infers that there was a new, and improved version. I was wondering how you can tell what that was? Has anyone ever seen one? The pictures you post are all from F1 versions, which seem to also have the problem.

In other news, my local dealer admitted that the 1990 Ducati Sport basically does not exist in their parts system. I was trying to get some swingarm shims to get the freeplay set up correctly. So, onto second source, Google. Came up with this

https://www.onlinemetals.com/merchant.c ... &top_cat=0

Shim washers are known as Arbor Shims, and come in a wide range of thicknesses. Since the pivot pin is 28mm, which is about 1.10", its pretty close to a 1 1/8" ID shim ( 1.125) so I ordered a set. I'll probably have some spares when I'm done, so if you are planning on taking off your swing arm in the near future, let me know, and I'll send what's left of the kit to you.

Next is to source some seals from the internet. Dealer couldn't find them either.

Cheers, Phil

Phil,

Stein Dinse http://www.stein-dinse.biz/ show a parts fiche for the Sport, and I've done a screen grab of what they say is still available shim-wise (I think...):

Daniel,
Well I have seen the additional brace on the right side, but have not seen the bracing by the shock mount. If we can find another one that looks like yours, we can confirm.

this looks like the same
http://p1.bikepics.com/2011/07/30/bikep ... 7-full.jpg

check this out. I guess you can`t get better pictures
http://www.ducati.ms/forums/129-parts-a ... t-new.html