GSXR gearbox issue

[jmw76]

Hi Guys,
Does anyone know whether you can put GSXR 1127 gears on GSXR 1052 shafts in a 1052 box?
Cheers

[DCRacing]

I don't see why not. just as long as you don't stuff with the primary ratio. I will have a look at the gear sets I have in the shed and find out. I thnk as long as you are keeping them matched you should be ok. I think Deano is the man to talk here tho

[jmw76]

Thanks for that.
Deano, any thoughts?

[Deano]

the 1052 has different shafts compared to the 1127. the 1127 gears are different compared to 1052. the selector drum and shifter forks are allthe same,

you may find it will go together but i couldn't say unless i had it all in front of me. the differences between the shafts and gears may be quite small but i really cant say for sure if it will work,

[jmw76]

Thanys guys.
I will have a play around and see what I find.

[jmw76]

Another thought.
I have read in numerous places of 750 6 speed swaps into 1100s. The general opinion seems to be that the 1100 gears are stronger, so don't do it! Does anyone know of or have experience with 750 gears breaking?
If so what breaks? The gear teeth or the drive dogs?
Does anyone know of the width of the gears in the Busa and GSXR1000 boxes? I would suspect that these are similar to the 750.
I would like to explore the 6 speed close ratio option for my race machine.
Any thoughts welcome and greatly appreciated.
Cheers

[Deano]

i spoke to a guy that was runnin water cooled 750 gearboxes in his 190hp gsxr1100w side car. he said there were 2 gearboxes in the 750w, 1 with 4 drive dogs on 1st and 2nd gears and one with 3 drive dogs.

he was running the 4 dog setup. he said that the drive dogs were the issue and if he didn't use the 4 dog gears the dogs would round off. once he changed to the 4 dog setup (and probably undercut them) they worked a treat.

you will have to use the 1100 clutch and 750 gearbox shafts, the 1100 clutch will either have to be converted to cable (easy) or drill the gearbox shafts to take the hyd setup (not as easy)

i am about to convert my gsxr race bike to cable clutch so i will let you no how it goes.

[DCRacing]

Hey Deano

I just converted the 86 GSXR race bike to a cable clutch, as you said easy, except i did it the hard way......drill and then die grinder to finish it all off, man those aluminium fillings get every where! but works great.

i was going to ask if you were running the 6 speed box or 5 as i have only the 5 and the 6 to compare back to back, which for obvious reasons isn't much use.

I do have the shortstroke 750 box but it is still in the motor at the moment. and only got a long stroke box out.

[jmw76]

Great advice.
Thanks a lot Deano.

I will hunt around for the right box.

I will probably have to drill the shaft as I am already set up for the hydaulic clutch (pedal in a car).
Cheers

Cheers

[Deano]

quote:Originally posted by DCRacing

Hey Deano

I just converted the 86 GSXR race bike to a cable clutch, as you said easy, except i did it the hard way......drill and then die grinder to finish it all off, man those aluminium fillings get every where! but works great.

i was going to ask if you were running the 6 speed box or 5 as i have only the 5 and the 6 to compare back to back, which for obvious reasons isn't much use.

I do have the shortstroke 750 box but it is still in the motor at the moment. and only got a long stroke box out.


i have a couple of 6 speed water cooled engines under the house. both fucked but good boxes in them. i personally dont see the need to put in a 6 speed box. with the torque of the 1100 it i always in the right gear. i did a track day on friday and i was running final gearign that would top out and about 240km on the limiter in 5th. i only saw a top speed of 226km according to the veypor but the point i am getting at is that on the track i was at i had only 5 gear changes for the whole track and that includes up and down the box. cant complain about that i think. if i had a 6 speed then it would be quie different. learing to ride better will out perform a 6speed gearbox comversion everyday of the week.

i rode my mates k4 600 track bike and apart from the rearsets and levers been in the wrong spots the thing handled so much beeter than the 7/11. i guess 12 years and 60kg weight difference will do that for you. as i get faster my bike will tend to want to run a little wide. i have to hang off more and man handle it more to get the result but it don't fill me with confidence. i guess i should look at adding a little more prelaod to the rear shock and see if that makes a difference

[Jazdiver]

Hey Deano, were you at the Island on Friday or Broadford?

[Deano]

broadford mate

[jmw76]

Hey Deano,
Interesting notes about your track day.
226 in 5th. I see about 218 in 5th at the island and I'm pushing 340kg and lots more drag I would suspect.
I just feel that 6 speeds will give me a better choice of ratios out of the turns so that I can keep it all on song.
Ran lap sim (a Bosch motorsport program) just to see if it gives any improvement. Lap time difference to 5 speed is likely to be marginal but is just in front.
What exactly is required if I need to go to cable conversion.
It would be nice to get rid of the push rod that gets damaged when you break a chain.
Cheers

[DCRacing]

I would think in a cart setup you would be able to make up a hydraulic slave cyl for it, you could rotate the clutch throw out lever on a cable clutch around and bolt on a bracket to some where on the motor and it would be all a go, might need to work out the travel on the slave from you master cyl, but a little playing around would soon have it.
and as far as the spacer for the clutch cover, i got a bit of alloy and placed the clutch cover on the alloy, clamped it and then scribed out the shape, then while it was clamped i drilled the holes using the cover as a guide for the angle, then usind a gasket on the other side of the alloy traced around it to complete the spacer, then i drilled a few holes cut out the bulk of the material and finished off with the die grinder.
with the bigger clutches you will need a bigger spacer on the 750 i only needed about 10mm the one i have on the 1100 is a bit bigger but i haven't bothered to measure it, will get around to it and let you know, i will take a few pictures of them both and post them for you.

[Deano]

quote:Originally posted by jmw76

Hey Deano,
Interesting notes about your track day.
226 in 5th. I see about 218 in 5th at the island and I'm pushing 340kg and lots more drag I would suspect.
I just feel that 6 speeds will give me a better choice of ratios out of the turns so that I can keep it all on song.
Ran lap sim (a Bosch motorsport program) just to see if it gives any improvement. Lap time difference to 5 speed is likely to be marginal but is just in front.
What exactly is required if I need to go to cable conversion.
It would be nice to get rid of the push rod that gets damaged when you break a chain.
Cheers



for your application i would say that 6 speed would be a useful modification, on a bike i am not so sure.

dc - i was just about to ask you what thinkness the spacer plate had to be.

any more info would be appreciated

[jmw76]

A 10mm spacer. Ouch!!!!
I have metal chassis tubes running down that side of the engine that hold all the rear suspension in place.
I don't like the prospect of removing the engine just to take off the clutch cover.
I guess I will have to drill the shaft.
Anyone tried this? I gather the shaft is quite hard. I have a lathe so should not be any real problem for me.
As for under-cutting the drive dogs. Anyone done this. What angle is the undercut? The 1100 box is already undercut to a degree. I have never had problems with it jumping out of gears. I would assume that the standard 6 speed is undercut also. Any ideas?
Cheers

[DCRacing]

http://www.streetfighters.com.au/forum/upload/1008265290269219.jpg

[DCRacing]

http://www.streetfighters.com.au/forum/upload/1008265290198735.jpg

[DCRacing]

http://www.streetfighters.com.au/forum/upload/1008265290265722.jpg

[DCRacing]

http://www.streetfighters.com.au/forum/upload/1008265290225572.jpg

[DCRacing]

These are the spacer plates that i have on the oil cooled gixxers, the 750 is 8mm because it has a smaller depth of clutch pack, the 1100 is 20mm due to the bigger clutch pack, i think it is a bit of over kill on the 1100 tho. i don't think they need that much space, essentially you only need the clutch to disengage which requires a relatively small amount of movement on the basket before the plates will start to slip, if it were in a daily ridden machine it might be a problem as it would spend a fair bit of time with the clutch in and the plates sliding, but on the race setup it would not get much sliding or riding of the clutch over all.
i did the 750 the rough way, you could probably get Azrael to cut 1 out with his water cutter and it would be perfect straight up.

[jmw76]

Hey DCR,
That is a big plate on the 1100.
I am not sure I have that much room to play with.
Drilling the shaft might have to be the trick.
Deano, you said you had some 750 box bits.
Are these surplus to your needs? I might be in the market for one.
Cheers

[Deano]

not really surplus unfortunately. you never no when you may need a new gearbox. sorry mate.

i am not sure it could be done that well on a water ject cutter as they actually have to be cut on an angle. i guess if you were to make a jig of some sort to hold it at that angle then happy days. i guess the only other thing is to no if the head ot the water jet will raise as the ally plate inclines up the jig.

thanks for the picks

[jmw76]

Yeah, no probs Deano. No harm in asking.
I will check elsewhere.
Any idea what year 750s have the 4 tooth dogs?

[Deano]

i think it is the later model w/cooled 750. 94/95 mod

[03gixxerpilot]

jmw76 im going to be pulling down a 86 gsxr 750 and a 96 gsxf750 today i will let you know what i find tonight

[03gixxerpilot]

Ok i have decided against pulling the gsxf apart but i have pulled down a '86 and '90 gsxr 750 both gearboxes are for all intensive purpuses the same, the input shaft having 4 dogs the the gears and the output shaft having 3 dogs on the gears. hope this helps.

[greg mulligan]

Iam just finished a hyper 1100 fitted with a 750 gearbox,got the gearbox shaft driled and gear undercut works fine .Ive had a few oilcooled and watercooled gsxr1100s fitted with 750 boxes in ireland and they all worked fine

[jmw76]

o3GP, what did you find you stripped those boxes?

[03gixxerpilot]

quote:Originally posted by 03gixxerpilot

Ok i have decided against pulling the gsxf apart but i have pulled down a '86 and '90 gsxr 750 both gearboxes are for all intensive purpuses the same, the input shaft having 4 dogs the the gears and the output shaft having 3 dogs on the gears. hope this helps.



as above, both boxes were in good condition with no signs of excesive were or problems, so much so that i wont have to replace any part of the gear boxes when the motor goes back together.

i have decided to use the gsxf motor without stripping it (there is no need to as it has good compression and good oil pressure)

[jmw76]

So.
It looks like there is a growing opinion that you can actually reliably use a 750 6 speed box on an 1100 provided that you ensure all the gears are under cut and that everything else is in good condition.
I believe that even the early 3 tooth dog boxes can take a bit more power than they were designed to (and probably shit better than the 4 tooth dog boxes).
1st gear on the 1100 5 speed box has only 3 teeth on the drive dog and they are not undercut.

I have read of an early turbo 1100 used for many years in land speed attemptes that used a 1987 6 speed box. (no idea what modifications were done)

Does anyone know of a good, cost effective place in melbourne that under cuts gears?
Has anyone attempted to undercut the drive dogs themselves?

Cheers

[jmw76]

Oops
That should have been shift not shit!!!

[jmw76]

Greg,
Did you get the gears on the output shaft undercut or did you just run as standard in your 1100 machines?

[Deano]

2nd gear seems to be the problem most of the time

[greg mulligan]

as far as knoow all gears wee done.makes a very smooth gearbox

[jmw76]

Yeah.
I can understand that 2nd would be the main problem.
You really do not use 1st all that often.
2nd is likely to be the gear that is most likely abused.

Anyone got any good advice on where to get undercutting done?
There doesn't apear to be much metal on some of the gears to undercut.

Cheers

[Deano]

powerflow or proflow (one of the 2) in geelong mate

[jmw76]

Thanks.
Any further clues. Cannot find them.

[Deano]

it popped up in a previous thread about a month ago. booster knows for sure send him a pm and he will tell you the exact details

[jmw76]

I think I found them.
Bruce @ Powerflow in Geelong, 03 5281 9388.
I will give them a try today.
Thanks guys.