GS tranny in a GT750 box

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water cooled
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Re: GS tranny in a GT750 bo

Post by water cooled »

R, it's my experience that you can push a lot more through the stock clutch. The basket actually sees bhp (crank HP). My bhp is about 145 and I've had the same basket since 2008.

The BDK application is a sidecar used in road racing. Two men plus lots of extra weight around corners etc. that's very different from drag racing which explains the basket failure on their site.
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Re: GS tranny in a GT750 box

Post by old racer »

tz375 wrote:Thanks guys.

I was already figuring that straight cut gears are a must above a certain level of power. On the BDK site there's a picture of a shattered basket and they say that above 120 HP the clutch ain't goi'n to take it any more.

Nice to hear that the twin triple could deal with all that torque without spinning the pressed on gear or shattering teeth. That gives me a lot more confidence and reduces the amount of work needed to fit the GSX750 trans. Did the double motor have a dry clutch and straight cut primaries or did it run a more or less stock trans? And how did you get past the huge 1-2 shift gap?
I use stock trans in everything,
1-2 shift gap.are we talking ratio if so not noticable.
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tz375
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Re: GS tranny in a GT750 box

Post by tz375 »

Thanks guys for all that input.

Yes the 1-2 reference was to the enormous gap between ratios on a JKL transmission - unless the motor makes power further up and doesn't fall in a hole. Mine is very mild and when I change from first to second it drops below the bottom of the power curve and takes a while to get back in its stride. I can always rev it past the top of the power curve and that brings revs up a little in second to help it move.

Maybe I should use clutch for 1-2 shift. That never occurred to me. Duh! :oops: I use an electric over air push button shifter. Until I get a different transmission in there, that might be the solution. And it's less work that swapping the transmission or building a second motor. I may just have to try that on this street bike. I built it to be great on the street not for the strip and the mix of parts and state of tune are not really suitable - but it's fun and nothing and no one is getting hurt, so why not.

Kevin, Good luck in GA later this month.
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tz375
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Re: GS tranny in a GT750 box

Post by tz375 »

Doesn't time fly.

Time for a tiny update.

GS750 trans slips in with the mods that Dave and Allan describe and have much better ratios

GSX750 is almost identical but a couple of ear dogs have changed and the output shaft is slightly longer than the SOHC model and it drops in with the same mods..

GS1100E. Same transmission as a 750 but slightly different dogs. Looks like it will slip in with the same modifications and a marginally taller/closer first gear.
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Re: GS tranny in a GT750 box

Post by Suzukidave »

Time does fly :( so ... which tranny are you going with ?
the older i get the faster i was
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Re: GS tranny in a GT750 box

Post by tz375 »

GS1100 I think. In each generation of gearbox, Suzuki changed a dog design or something else, so I will assume that the 1100 is the best of the bunch, but for a street motor any of them would work. The real difference between SOHC and 16 valve output shafts is the length of the splines. Either will work, but the 16 valve has more scope for working with really wide wheels
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Re: GS tranny in a GT750 box

Post by MikeD »

Any chance the original contributors can go back through the early posts in this thread and fix the links to the broken photos?

Just bought an 2001 GSX trans for the long output shaft I need (main shaft, counter, shift forks, and drum) for $18

Anybody in the US offering their machining services in exchange for some "green gease"/$$?
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Re: GS tranny in a GT750 box

Post by Suzukidave »

Hummm , not too sure that will fit in , we were useing the 77~78 GS 750 tranny but in the process of this posting others were found to fit in .
the older i get the faster i was
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Re: GS tranny in a GT750 box

Post by MikeD »

Suzukidave wrote:Hummm , not too sure that will fit in , we were useing the 77~78 GS 750 tranny but in the process of this posting others were found to fit in .
tz375 wrote: GSX750 is almost identical but a couple of ear dogs have changed and the output shaft is slightly longer than the SOHC model and it drops in with the same mods..
ordered it based on the above. we'll see I guess, but it would be my luck...

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Re: GS tranny in a GT750 box

Post by Suzukidave »

Looks like a 6 speed , if it works this will be a new trick :up:
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Re: GS tranny in a GT750 box

Post by Suzukidave »

MikeD wrote:Any chance the original contributors can go back through the early posts in this thread and fix the links to the broken photos?

Just bought an 2001 GSX trans for the long output shaft I need (main shaft, counter, shift forks, and drum) for $18

Anybody in the US offering their machining services in exchange for some "green gease"/$$?
Sorry about no pictures to the early links , i lost my server .. still have the pictures but on a different server .
the older i get the faster i was
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Re: GS tranny in a GT750 box

Post by MikeD »

Suzukidave wrote:Looks like a 6 speed , if it works this will be a new trick :up:
"if" being the huge qualifier...
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Re: GS tranny in a GT750 box

Post by tz375 »

MikeD wrote:Any chance the original contributors can go back through the early posts in this thread and fix the links to the broken photos?
Just bought an 2001 GSX trans for the long output shaft I need (main shaft, counter, shift forks, and drum) for $18
Anybody in the US offering their machining services in exchange for some "green gease"/$$?
What bike is it from? Is it a GSX750R by any chance? A GSX-R trans is too wide by about 7mm IIRC.
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Re: GS tranny in a GT750 box

Post by MikeD »

tz375 wrote:
MikeD wrote:Any chance the original contributors can go back through the early posts in this thread and fix the links to the broken photos?
Just bought an 2001 GSX trans for the long output shaft I need (main shaft, counter, shift forks, and drum) for $18
Anybody in the US offering their machining services in exchange for some "green gease"/$$?
What bike is it from? Is it a GSX750R by any chance? A GSX-R trans is too wide by about 7mm IIRC.
2001 Suzuki Katana GSX750
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Re: GS tranny in a GT750 box

Post by tz375 »

Please measure it across the gears on both shafts and I'll see if it can fit without resorting to conversion to full cassette style trans.
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