900 motor in my Sport?

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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ducinthebay
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model: 750 Sport
year: 1990
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900 motor in my Sport?

Post by ducinthebay »

I have a chance to pick up a 900ss motor with some mods done to it for $400.
I have heard that it drops right into the frame. Has anyone else done this? What other mods do I need to do to it? I know the charging system is a match, and the ignition system will require a bit of work. Can I get those stock 900 carbs inside the Sports frame?

Any input or advise is welcomed.

Cheers,
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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jcslocum
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Re: 900 motor in my Sport?

Post by jcslocum »

I "think" it will fit. But I can't give a deinitive answer. There are others here that will know tho. Gerhard???

$400 is cheap so don't miss it!!
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paso750
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Re: 900 motor in my Sport?

Post by paso750 »

can`t give a definitive answer either as I have no personal experience. It`s definetely possible to fit it, but the question is if it needs any modification.
A friend of mine with a Cagiva Elefant changed his 750 with a 900cc engine. The engine fitted with no mods to it or the frame required. If the bike and new engine are from a similar model year there are no problems he says.
I can say that the bolt of the front engine mount is smaller on Supersport and Monster compared to the one on the Paso. I`m using a 780cc kit for SS/Monster and the thread had to be made larger. No problem though.
The only point I`m wondering about is the swingarm mount on the engine. If you want to put a SS/Monster engine in a Paso you need to machine a piece of the engine`s swingarm mount as the Paso swingarm is not as wide as the swingarm of the newer models.
So for me the only point to clarify is if the engine`s swingarm mount of a Sport has the same width as the one of a Paso or not. If it`s not it`s likely to be the same as on the Supersport which would make things easy.
The inner width of the front section of the Paso swingarm is 15,4cm, with the spacers in place 14,2cm. So now you can check your Sport swingarm and compare.
Mikunis don`t seem to be a problem, there are some guys here using them in their 750S.

G.

PS Jon, why do your recent posts show Oct.8 as date in the main forum overview ?
Tamburinifan
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Re: 900 motor in my Sport?

Post by Tamburinifan »

Exhaust pipes generally don´t match between 750-900, could be a problem.
750 pipes are also thinner, you need the 900 pipes.
Gert

907 I.E. -91
M900 -97
MTS 1100s -07
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paso750
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Re: 900 motor in my Sport?

Post by paso750 »

some aftermarket companies name the same exhaust can model number for 750 and 900 engines so this may work but Gert is right you`ll need a different header as the cylinders are higher.
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ducinthebay
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Re: 900 motor in my Sport?

Post by ducinthebay »

The swingarm issue can definitely be a sticking point, but fortunately, the Sport swingarm is basically the same pattern as the SS, so putting an SS swingarm is an easy swap with the motor. Shock mount is the same, and shock length is the same, so no problem. My bike was already modified to have an SS swingarm, so I already have one.

I picked up a set of stock headers with the motor this morning, and the ignition boxes.

He didn't have carbs, so I will probably just use my 36 Dellortos for a while and see how they work.

Cheers,
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.
Tamburinifan
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Re: 900 motor in my Sport?

Post by Tamburinifan »

If you could share the swap w pics, comments etc it would be nice to follow
& helpful to others! :thumbup:

Best of luck!
Gert

907 I.E. -91
M900 -97
MTS 1100s -07
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jetboy
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Location: oakland, ca, usa

Re: 900 motor in my Sport?

Post by jetboy »

if you need a second pair of hands give me a holler -

and i may be wanting that radiator mount plate if your keeping yours up front - ill trade ya my plate, its all buffed out and shiny!
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ducinthebay
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Re: 900 motor in my Sport?

Post by ducinthebay »

Hey jetboy, I'll gladly trade you cam covers. Did you get that 900ss oil cooler?
Anyone take an oil cooler from an SS motor and hang it on a 750 motor?
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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jetboy
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Joined: Sat Nov 08, 2008 3:51 am
model: 750 Sport
year: 1990
Location: oakland, ca, usa

Re: 900 motor in my Sport?

Post by jetboy »

guy in hayward has one, said 50 bucks but i got to call him and arrange a time. i work all tomorrow so maybe during the week i can pick it up
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