Slipper clutch conversion project

[JEEPRUSTY]

What a grand project.
Pics are an awesome thing so keep em coming.

[ashdricky]

Here is the GSXR clutch next to the Transmission out of a 78 GS550.


And here is the actual Back Torque limiting mechanism,


The splines match perfectly....

[ashdricky]

By Friday we will have another 550 clutch and then I can match up the baskets and sort out the possibilities.

[ashdricky]

the 550 clutch is here now and within a few hours I should have photos up for comparison, anyone have any direction or place to start now that i have both? My bike is in storage temporarily so I cant test fitment yet, but i figure that the 550 clutch should give an accurate perspective

[GregT]

Did the center hub fit the splines of the 550 mainshaft ? Looking at one of your pics it would seem so...
Don't change the basket/primary gear just run the slipper center in the 550 basket. Use 550 steel plates and the GSXR fibers.

Looks like it's all feasible. I was half expecting the GSXR center to have fine splines like the air/oil cooled motors.

[ashdricky]

Did the center hub fit the splines of the 550 mainshaft ? Looking at one of your pics it would seem so...
Don't change the basket/primary gear just run the slipper center in the 550 basket. Use 550 steel plates and the GSXR fibers.

Looks like it's all feasible. I was half expecting the GSXR center to have fine splines like the air/oil cooled motors.

Thanks Greg I am in the process of assembling what you just described,
The GSXR clutch is possibly 24mm taller than the gs clutch so Im not entirely sure how I will fit everything

[ashdricky]

So I have assembled the parts as suggested, ant there are several issues that I came across;
1) The gsxr clutch has 8 friction discs whereas the 550 only has 7, which would require an additional set of friction plates to be purchased so the gap can be closed.
2) Eventually when the plates and friction discs wear down it will cost 3x what a usual replacement dose as a gsxr plate set is required in addition to the two gs sets.
3) The metal discs from the gsxr clutch only make contact with 50% of the surface area of the 550 friction plates.
4) The slipper mechanism prevents the inner portion of the clutch from resting properly within the basket.

What if i Swap the drive gears and can align the gsxr clutch correctly?

[GregT]

The simplest solution is to make the GSXR center fit in the 550 basket - Can you post a pic of the two centers side by side so we can see the length difference please.
It may be possible to simply machine back the outer edge of the GSXR center hub.
A pic of the 2 types of steel plate would let us know where the diameter difference is too.

Thanks

[ashdricky]

I am watching a friend's house for the weekend, Ill take those photos as soon as I can get back home. hopefully Monday.

[Nessism]

I'd remove the aluminum basket assembly from both hubs (need to grind off the rivets and punch them free). Next you need to figure out how to get the GSXR basket mounted to the 550 gear.

Good luck figuring out how to get the clutch cover back on with that tall hub. The drag racer guys machine a spacer when they install certain types of tall clutches. Seems that something similar is in order here.

[ashdricky]

I'd remove the aluminum basket assembly from both hubs (need to grind off the rivets and punch them free). Next you need to figure out how to get the GSXR basket mounted to the 550 gear.

Good luck figuring out how to get the clutch cover back on with that tall hub. The drag racer guys machine a spacer when they install certain types of tall clutches. Seems that something similar is in order here.

Ive come up with a solution for the tall clutch, I would mill a circular recess 26mm larger than the diameter of the gsxr basket in the clutch cover, making sure it is centered properly with the clutch axis. Then mill through the cover creating an opening 6mm larger than the clutch. Now I would have a "shoulder of 10mm on each side and then a gap of 3mm between the clutch and the cover as it continues through the cover into now open space. (I think this is the simplest way as I need to retain the kick start, therefore cannot easily move the entire cover out ~50mm) then I would mill an aluminum cover to fit over the opening and use the 10mm shoulder to mount the cover. Greg what do you feel about this idea rather than the hybrid clutch? I was thinking the gsxr clutch assembly is more developed and probably more robust than the 550 unit, which I will need when we start looking into developing power.

Here are the two hubs side by side to give a perspective of the height difference.

[ashdricky]

so after several hours of working with the machinist, we came to the conclusion that a custom basket had to be machined, almost identical to the gsxr basket, but with the correct dimensions to accept the 550 drive gear and springs.

[GregT]

It's difficult to make any judgement without the parts in hand...

As far as the 550 clutch goes, it's over engineered for the std output and I'm pretty sure it would accept up to 90 plus HP. The GSXR clutch has a couple more plates and will we know accept over 120hp...
The GS1000 clutch - which I am intimately familiar with - will take well over 130hp in pretty much std form...better springs of course. The 550 isn't much smaller.

My own first instinct would be to try and mod the OE center to accept the slipper bits but without handling it....I just don't know.
Is your machinist worried about the thickness of the OE hub after machining ?
The whole "new basket" scenario is potentially difficult too. If you can use the GSXR basket on the 550 primary gear, that's probably the least work.
Spacing the cover out is the least of the problems.

As an aside, I understand there's a remit going forward here in NZ banning slipper clutches in our Vintage racing....

[ashdricky]

It's difficult to make any judgement without the parts in hand...

As far as the 550 clutch goes, it's over engineered for the std output and I'm pretty sure it would accept up to 90 plus HP. The GSXR clutch has a couple more plates and will we know accept over 120hp...
The GS1000 clutch - which I am intimately familiar with - will take well over 130hp in pretty much std form...better springs of course. The 550 isn't much smaller.

My own first instinct would be to try and mod the OE center to accept the slipper bits but without handling it....I just don't know.
Is your machinist worried about the thickness of the OE hub after machining ?
The whole "new basket" scenario is potentially difficult too. If you can use the GSXR basket on the 550 primary gear, that's probably the least work.
Spacing the cover out is the least of the problems.

As an aside, I understand there's a remit going forward here in NZ banning slipper clutches in our Vintage racing....

We removed the primary gears from both baskets with the idea that we would fit the 550 gear to the gsxr basket, we got hung up when it came to the spring configuration, which is radically different.
Ill be sure to take photos when I get home.

the thought of doing all of this just to be banned from competition makes me ? the project, but for now we will continue to move forward.

[ashdricky]

I just had a thought, what would be the results of an unsprung clutch? what if I just fastened the 550 primary drive gear to the gsxr basket without dampening springs? Clearly the clutch would behave in an abrupt manner, but would it be to the point that the bike is unrideable? We are also running a quick shifter and will not use the clutch on upshifts over 7000 rpm.