750 Sport engine swaps? (swingarm bearing trouble)

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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pasomatic

750 Sport engine swaps? (swingarm bearing trouble)

Post by pasomatic »

Hi All,

I'm a new member, just found this board. I've got a blue '88 Paso that's been to almost every state in the US, an '88 Paso with custom bodywork for track use, and a '750 Sport (1990 I think?).

I got the 750 Sport for cheap as an insurance job from a friend, for bodywork damage, bent subframe, and a bent wheel. I fixed the bodywork, straightened the subframe, and had the wheel straightened, then found out that the previous owner had tried to keep using a totally worn out front sprocket until he could sell the bike, and had the chain tightened enough that the swingarm bearings are worn out, giving enough play in the rear wheel that it's pretty obvious when you ride it.

It's been sitting around for a couple of years now, waiting for me to do something about it, either splitting the cases myself or paying someone else to do it (you have to split the crankcases to replace the swingarm bearings on this engine).

I've seen some engines go by pretty cheap on Ebay, maybe cheaper than paying a shop to do the work for me, although I haven't had the job quoted.

Does anyone know if any other engines will fit a Sport? The Paso uses the same cases, but they're not machined to carry the swingarm bearings in the crankcase.

I would consider something requiring minor frame modifications, but I've got too many projects already, so anything radical (like a 748, which I assume won't drop right in) is out.

Anyone have any suggestions? Anyone ever had to replace the swingarm bearings in a Sport? I haven't actually priced the job out, but I'm guessing that a total tear down and reassembly isn't cheap.

Any advice (except "sell it to me cheap") is appreciated.

Thanks!
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samandkimberly
Posts: 149
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model: 907 I.E.
year: 1993
Location: Boston, MA

Re: 750 Sport engine swaps? (swingarm bearing trouble)

Post by samandkimberly »

Don't change the bearings, ream them out and change the pin! It's even possible that Ducati sold an oversize pin for this at one point. You'll need a cheap adjustable reamer (probably $30.00) and an oversized pin. A machine shop could probably custom grind one for cheap - it's a very simple part.
User avatar
samandkimberly
Posts: 149
Joined: Thu Apr 03, 2008 4:38 pm
model: 907 I.E.
year: 1993
Location: Boston, MA

Re: 750 Sport engine swaps? (swingarm bearing trouble)

Post by samandkimberly »

I double checked this. The F1 Ducatis used the same swingarm pin setup in many, if not all models. P/N 066749040 is for a standard pin, xxx9045 is .03mm over, xxx9046 is .05mm, and xxx9047 is .1mm. There were oversized thrust washers available too, to compensate for side play.
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