Swingarm? WTB

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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ducinthebay
paso grand pooh-bah
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model: 750 Sport
year: 1990
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Re: Swingarm? WTB

Post by ducinthebay »

Yeah, I found that post, and wish I had seen that when he posted it a couple years back. Sold for $350.

Since that was purchased in the last 10 years, I will have to say that it is the most recent version of the part. two vertical braces, angled braces near the shock mount, and triangle braces inside the wheel space. Lots of added material, and I dare say a bit stiffer.

I wonder if you could still get Ducati to replace a broken swingarm on a Sport? I know that you can still get the alternator upgrade on a 1998 ST2 on warranty. Wonder how many of these are on the shelf?

Cheers, Phil
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
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Danielmc
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model: 750 Sport
year: 1990
Location: Taunton, England

Re: Swingarm? WTB

Post by Danielmc »

BMW are still honouring a recall on wheels fitted to bikes in 1977, but I doubt there's a load of Verlicchi swingarms lying around in a warehouse in Italy somehow...
Andrew2
paso grand pooh-bah
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model: 750 Sport
year: 1988
Location: Wollongong,Australia

Re: Swingarm? WTB

Post by Andrew2 »

paso750 wrote:check this out. I guess you can`t get better pictures :)
http://www.ducati.ms/forums/129-parts-a ... t-new.html
I spotted that yesterday when I was trying to find some info on swingarms for Phil but decided not to post it in case it upset him :lol: :lol: :lol: :lol:

Cheers
Andrew
Andrew2
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Re: Swingarm? WTB

Post by Andrew2 »

Hey Phil,
go and check out the swingarm in my resto thread.It had cracked and the previous owner had it braced when he rewelded it.

Cheers
Andrew
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ducinthebay
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Re: Swingarm? WTB

Post by ducinthebay »

Andrew,
I saw that brace on your swing arm, and have seen it several other times on Sports. I am assuming that it is a later modification, or a previous owner trying to upgrade when it cracked. Most of the cracks i have seen are at the welds at the big cross brace. You may have a warranteed swing arm, or at least a later one.

Another datapoint is the micro fiche from Stein-Dinse for the 1991 750 SS.

http://www.stein-dinse.biz/bilder/auto/ ... 554429.jpg

Interesting mix of stuff on that bike. The swing arm pivot looks like the 28mm pivot pin and front of the swingarm looks like the Sport series, but the rest of the swingarm looks like the aluminum one from the 900SS. Someone else mentioned this odd swing arm in some other post. Not quite sure where that particular model was ever sold.

Cheers, Phil
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
Andrew2
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Re: Swingarm? WTB

Post by Andrew2 »

Steve ( the original owner ) had it welded up locally.I just went and had another look at it and it's pretty rough.What year steel swingarm did you use and what mods needed to be done to do it.I'm thinking I might keep an eye out for a used steel one for later.

Cheers
Andrew
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ducinthebay
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Re: Swingarm? WTB

Post by ducinthebay »

Andrew2 wrote:What year steel swingarm did you use and what mods needed to be done to do it.I'm thinking I might keep an eye out for a used steel one for later. Cheers Andrew
The steel swing arm I have was from a 750 SS, any year, they're all the same. But trust me, its not a simple modification. It requires cutting parts off, machining, a lot of welding, and some good fabrication skills. I'll take some photos and describe how I think it was done, although I don't know who did the actual work. I can't recommend it unless you are a good welder and fabricator. In general, the steel swingarms are cheap, so just keep your eyes open, and you can pick one up for less than $50, and get your welder primed with beer.

Cheers, Phil
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
Andrew2
paso grand pooh-bah
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year: 1988
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Re: Swingarm? WTB

Post by Andrew2 »

Thanks Phil.

Cheers
Andrew
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ducinthebay
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Re: Swingarm? WTB

Post by ducinthebay »

OK, Here's one way to put a steel SS swingarm on a Sport.
The big difference is that the Sport has a 28mm pivot pin, and about 155mm wide cases, and pivots on a bronze bushing in the cases.
The SS series has a 19mm pivot pin, and cases are about 190mm (?) wide, and pivots on two sets of needle bearings on either side.

The bushings in the cases are pressed in place, then reamed to reach alignment, so the holes in the cases are not necessarily aligned.

- So, take an SS swing arm, and cut off the forward arms at the major cross brace.
- Machine off the flanges around the pinch bolts, and weld on a little more meat for good measure.
- bore these assemblies to 28mm
- Assemble onto your pivot pin to get them to align, and set the inside dimension a couple mm's wider than your cases. You need to shim it anyway.
- First tack, then weld up the arms onto the cross brace. Confirm that the pivot pin and rear axle are aligned and parallel. Adjust with a hammer before finishing welding.
- With sheet metal, make some triangle fill pieces to brace in the outsides.
- Add some side plates to close up the sides.
- No need for paint if the seals leak. It just gets covered in oil and preserves it, sort of.

Image

Image

Image

Image

Good luck.
Phil
Last edited by ducinthebay on Mon Apr 15, 2013 4:31 am, edited 1 time in total.
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
User avatar
ducinthebay
paso grand pooh-bah
Posts: 1323
Joined: Sat Sep 03, 2005 12:00 am
model: 750 Sport
year: 1990
Location: SF Bay Area

Re: Swingarm? WTB

Post by ducinthebay »

And the real reason I am searching for a new swing arm.

Image

The sprocket bolts beat the tar out of the inside of the swing arm. I will be taking a torch and hammer to it this weekend in hopes I can get the chain adjuster to slide in the arm again. Stay tuned.

Cheers, Phil
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
Andrew2
paso grand pooh-bah
Posts: 574
Joined: Thu Oct 27, 2011 7:47 am
model: 750 Sport
year: 1988
Location: Wollongong,Australia

Re: Swingarm? WTB

Post by Andrew2 »

That's a lot more work than I expected.Thanks for taking the time to explain mate.

Cheers
Andrew
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ir_joep
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year: 1989
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Re: Swingarm? WTB

Post by ir_joep »

That is not realy a bolt-on conversion :D .

In the mean while I have taken a look at my swingarm 750 sport '90 and can tell you that is has the bracing in place. Looks original to me.

Strange enough my alu swingarm from a post 91 ss does not have any bracing whats so ever.

Just for the record.

Cheers Joep
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