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Posted

Sorry to put a spanner in the works guys but,

GSXR1100wp.

Big end journal 41mm. Crank pin 39.9mm.

GSXR750wr.

Big end journal 37mm. Crank pin 33.9mm.

Figures from Factory manual. :|

  • Like 1
Posted

Thats what i wanted to know. Bugger!  New crankcases then. Grrrr. 4mm too big. Maybe bore 750 case out to 1100 size but i expect be much cheaper to get second hand 1100 cases?

Posted

what if a guy used the 750 bottom w/ crank and the 1100 top? I know Madb said that the 750 gear box would hold up to the torque. I am just trying to work with what I got at home with minimal purchases. I have the 1994 750 motor and a 1996 1100 motor. crack in cylinder wall on 750 and crack in 1100 case. any ideas? 

Posted (edited)

Cheapest option would to source another barrel and matching pistons for 750. Use that till you can source 1100 casings. Or have 1100 casings welded?

Edited by Madb
Missed words
Posted
21 hours ago, bluedog59 said:

Sorry to put a spanner in the works guys but,

GSXR1100wp.

Big end journal 41mm. Crank pin 39.9mm.

GSXR750wr.

Big end journal 37mm. Crank pin 33.9mm.

Figures from Factory manual. :|

Main bearing diameters are the same between 1100 and 750. Crankpins are matched to conrods, so 1100 rods must be used with 1100 crank, and 750 rods must be used with 750 crank. You have to transplant all the 1100 gear in the crankcases to the 750 crankcase to use them. Done it, raced it, no problems.

  • Like 2
Posted

Cool. So mains are the same thro the range. Brill. Thought bluedog59 were refering to mains!. I new the big end were different on the 900/1100.  So still a go on swaping internals from 1100 to 750 casings. Yay! 

Posted
14 hours ago, mrgreen98ski said:

on a 900/750 what all is used. the whole rf900 but the head?

If you use the rf900 engine then its just means using the 750 head on the 900. But do use rf900 head and base gaskets.(y)

Posted (edited)
6 minutes ago, bluedog59 said:

So what combo did you run ? 

750 runs 18mm piston pin

1100 runs 20mm piston pin.

1100 crank rods and pistons with the 1100 gearbox and clutch. Just swap everything over to 750 cases.

Edited by Madb
Spelling. !!
Posted

I see. I'm using a 750 in the frame I'm making but have both so I was curious about what combo's I could do in the future. I'm using the 1100 sump and hoping to convert to 1100 hydraulic clutch to tidy up having a cable hanging out in the breeze. 

  • Like 1
Posted
1 hour ago, FJD said:

so - are the crankshafts interchangable between 750&1100 cases ?

Yep!  It seems so. Just make sure you match up your main bearing shells. Just waiting on comformation from mrgreen98ski.

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