Gs1000 motor into a 750

[jb]

Hi just wondering if anyone on here has fitted a 1000 motor into a 750 frame and what sort of a job it is...... 

I know the gsx is an easy conversion from 7 - 11 but don't have as much knowledge with the gs 

[kiwi]

Its not easy but is doable, iirc big pain to squeeze engine in and out, plus fuel tap needs re-positioning as close to carbs, but all problems can be overcome. 

The picture is a friends race weapon similar problem but gsx1100 engine.

[gs7_11]

Yes, I've done it. It's not too bad a job, but you'll need new mounting plates.

 

[wraith]

A mate had a gs7/10 for years, told me it was a strate swop, just needed to tweek the mounts/ swop/interchange/mixup the 750 and 1000 mounts, he was even using the 750 airbox as it was a all year round bike.

Not done it myself so only repeating what I was told, as I was thinking of doing myself when I had a spare 1000 motor.

[gs7_11]

Depends how you define 'fit'!

I wanted the job done right and where I worked had access to facilities to get some heavier duty brackets made, with the right joggles in and such. I've still got the drawings I did. Not knocking anyone else's work, but I found none of the 750/1000 brackets to be good enough for me. Each to their own though.

The 750 Airbox does fit and work though, as does the 1000G Airbox if you have CV carbs. I've had both on mine.

Edited February 20, 2023 by gs7_11

[jb]

Thanks for the advice, much appreciated......new engine mounts and moving the fuel tap sounds good, no frame tubes to cut and shut.....gives more chassis options 

[Swiss Toni]

9 hours ago, gs7_11 said:

 

I wanted the job done right and where I worked had access to facilities to get some heavier duty brackets made, with the right joggles in and such. I've still got the drawings I did.

How about putting them up, and the mods maybe 'Stickying' them for future reference? Can't have too much info. 

[gs7_11]

4 hours ago, jb said:

Thanks for the advice, much appreciated......new engine mounts and moving the fuel tap sounds good, no frame tubes to cut and shut.....gives more chassis options 

I don't think you need to move the fuel tap. I haven't, with both standard and Pingel taps. Loads of room.

 

3 hours ago, Swiss Toni said:

How about putting them up, and the mods maybe 'Stickying' them for future reference? Can't have too much info. 

Sure no probs. Shall I put them in this thread or is there somewhere else?

[Swiss Toni]

I think this thread's ok. If not, mods will move it to where it's better served! Maybe in 'The Vault' somewhere? I was always under the impression, the 1000 motor was both slightly smaller and lighter than the 750. So should be no bother in the transplant. There again....?

[gs7_11]

4 minutes ago, Swiss Toni said:

I think this thread's ok. If not, mods will move it to where it's better served! Maybe in 'The Vault' somewhere? I was always under the impression, the 1000 motor was both slightly smaller and lighter than the 750. So should be no bother in the transplant. There again....?

I found it easy enough. It's certainly lighter and shorter, front to rear, no kickstart. I think it's taller however.....you can't get the head off in the frame without undoing the engine mounts.

You can see when you fit the Airbox that the engine is *almost* a perfect fit, but not quite, if you look at the line between the side panels and Airbox.

[gs7_11]

On ‎16‎/‎03‎/‎2018 at 12:45 PM, Swiss Toni said:

I think this thread's ok. If not, mods will move it to where it's better served! Maybe in 'The Vault' somewhere? I was always under the impression, the 1000 motor was both slightly smaller and lighter than the 750. So should be no bother in the transplant. There again....?

As suggested, here's the drawings  for anyone who might find them useful. Usual disclaimer..... they worked for me and I had them done nearly 20 years ago, bike's still going strong, but try them at your own risk.

 

Edited March 17, 2018 by gs7_11

[Suzunki1989]

Hi, does anyone still have the motor mounts pictures? I cant download or view them. Much appreciated. Thanks!

[gs7_11]

On 2/17/2023 at 11:25 AM, Suzunki1989 said:

Hi, does anyone still have the motor mounts pictures? I cant download or view them. Much appreciated. Thanks!

I can repost the drawings, but they're on my PC and we've got a power cut here at the moment so you'll have to wait 

[Mike711]

On 3/16/2018 at 12:55 PM, gs7_11 said:

I found it easy enough. It's certainly lighter and shorter, front to rear, no kickstart. I think it's taller however.....you can't get the head off in the frame without undoing the engine mounts.

You can see when you fit the Airbox that the engine is *almost* a perfect fit, but not quite, if you look at the line between the side panels and Airbox.

I had a 1000 motor in my 750 then swapped it to an 1100ET & can confirm the head & barrels can be removed in situ without touching engine mounts.

[Duckndive]

Yeap the original 7-10 did it many moons ago 

Very old scanned pic from USB days 

[gs7_11]

On 2/17/2023 at 11:25 AM, Suzunki1989 said:

Hi, does anyone still have the motor mounts pictures? I cant download or view them. Much appreciated. Thanks!

Here's my drawings, attached.

 

1 hour ago, Mike711 said:

I had a 1000 motor in my 750 then swapped it to an 1100ET & can confirm the head & barrels can be removed in situ without touching engine mounts.

I can't on my 1085 engine. Don't know how the 1100 differs, or maybe depends on the exact mountings?

[Suzunki1989]

Thank you for the drawings! I have a 1979 suzuki gs750. It runs and drives really well, it's all original. But I have 2 GS1000 engines laying around so I might upgrade her a bit :-)

[TonyGee]

41 minutes ago, Suzunki1989 said:

I might upgrade her a bit

you won't regret it 

[Crabbypants15]

This thread has been amazing, I recently got a '79 engine in my '78 frame, but I think I'm running into fuel/air/exhaust issues. Mechanic said it was running rich, does anyone know if the carbs need to be rejetted? I'm also using a 750 Delkevic exhaust system, not sure if that is part of my problem too...

[Jonny]

On 2/20/2023 at 1:32 PM, Mike711 said:

I had a 1000 motor in my 750 then swapped it to an 1100ET & can confirm the head & barrels can be removed in situ without touching engine mounts.

Really? That’s interesting because I have an 1100ef motor in a ‘78 750 frame and the engine has to come out to take the heads off. It’s about an inch too short on clearance.

Edited July 29, 2023 by Jonny

[Mike711]

On 7/28/2023 at 11:48 PM, Jonny said:

Really? That’s interesting because I have an 1100ef motor in a ‘78 750 frame and the engine has to come out to take the heads off. It’s about an inch too short on clearance.

 

[wraith]

On 7/28/2023 at 9:25 PM, Crabbypants15 said:

This thread has been amazing, I recently got a '79 engine in my '78 frame, but I think I'm running into fuel/air/exhaust issues. Mechanic said it was running rich, does anyone know if the carbs need to be rejetted? I'm also using a 750 Delkevic exhaust system, not sure if that is part of my problem too...

Can you expand on this, a 79 engine? 1000/850/750/550???

78 frame again which? 

What's the carbs ? 

Small bits but stops use guessing on wether you put a gs1000 engine in a 750 or the other way round and if the carbs are 1000 or 750 and if they are CV or slide and are you using airbox or filters is the exhaust open race type or quite street all the above will/could affect the jetting etc

[gorbys]

Would be interesting to compare these drawings to the ones I have for my gsx1100 into a gs750 frame swap. Perhaps they're the same? 

[Mike711]

11 hours ago, gorbys said:

Would be interesting to compare these drawings to the ones I have for my gsx1100 into a gs750 frame swap. Perhaps they're the same? 

The mounts are the same, I originally had a GS1000 in my 750 but swapped it for an 1100et without any problems.

[gs7_11]

Well, each to their own. Maybe it depends in how you line the engine up or something? But I can confirm that using my mounts, you definitely can't get the head off without loosening the front mounts.