Slipper clutch conversion project

[ashdricky]

Yes, Dogma got it right...The Kiwi who did that clutch conversion had way too much time and CNC machining available to him....

The shaped insert answer like he used - but simpler shapes - is probably the way to go. Aluminium inserts for the gear bored to match the pitch circle diameter of the 3 basket retaining fasteners should be do-able.

You're dealing with a lot less torque and horsepower than the TL so three 10mm retaining bolts will be adequate IMO. You may want to look at Button head or even countersunk head fasteners as room at the back of the gear will be limited. If you use the original steel back plate from the 550 gear and redrill for the new hole location, after assembly the bolt/screw heads can be spot welded (TIG) in place for security.

So I was able to drop off the basket at my local race shop (Fast by Gast) and should get the opening in the basket enlarged so that the primary gear can be fit, once I get those pieces back I can look into locations for the bolt holes. I'll be sure to post updates ASAP.

 

[AJ]

I'm sort of wondering why in the world you feel a wee 550cc four cylinder engine needs a slipper clutch in the first place.

LOL! That's exactly what I was thinking.

Still, I admire the desire and the engineering initiative.

 

[GregT]

I'm sort of wondering why in the world you feel a wee 550cc four cylinder engine needs a slipper clutch in the first place.

There's no doubt that slipper - or back torque limiting - clutches have changed how you can ride in roadracing. Even the 550 has enough crank mass that corner approaches are done with some restraint - change down. run the revs down, change down again etc....Slipper clutches simply allow the rider to bang down the appropriate number of gears for the corner without worrying about rear wheel lockup or over revving.

Whether they're appropriate for Vintage or Post Classic racing is an argument which is just being aired here in NZ. Personally I say no as part of racing these dinosaurs is having to ride them in the fashion they were originally.

The OP here does not appear to have to worry about race regs at this point so i'm happy to offer advice. And of course if they do become legal here in NZ, I've seen some of the problems.....

 

[ashdricky]

Update: I stopped at Fast by Gast yesterday and the clutch machining is in line behind several other jobs. On a side note, I am leaving the country on Sunday, and will be over-seas for six weeks, So I don't foresee any developments on this project until I return.

Im a little surprised that Dansofield hasn't noticed this project as a BTL clutch would be a nice addition to the 550 he is racing in the UK.

 

[ashdricky]

So I have been in Europe for 6 weeks now working for my father, and the other day I got a call from my friend back in the states who picked up the clutch basket from the machinist. he then sent these photos, I appologize for the poor quality. Also GregT has informed me that the splines on the input shaft for the gear box are the same on the larger bikes as well.

k

 

[GregT]

You should really confirm the spline interchange with Agemax. If they are tha same all it means is that the late GSXR600 clutch hub is a starting point for a slipper conversion. I can confirm that the GSXR1000 spline is quite different to the early GS's.

What is stopping a lot of us from going ahead are the sanctioning body rules....Given that the ZX7 appears to have been the first sportbike marketed with a slipper clutch - in 1988/89 - no body I know of will yet accept slippers in forgotten era/pre 82 or whatever name it goes under where you are....

 

[ashdricky]

You should really confirm the spline interchange with Agemax. If they are tha same all it means is that the late GSXR600 clutch hub is a starting point for a slipper conversion. I can confirm that the GSXR1000 spline is quite different to the early GS's.

What is stopping a lot of us from going ahead are the sanctioning body rules....Given that the ZX7 appears to have been the first sportbike marketed with a slipper clutch - in 1988/89 - no body I know of will yet accept slippers in forgotten era/pre 82 or whatever name it goes under where you are....

I didn't take road racing into consideration when I started this build, the next bike I build might be track only, this bike is just supposed to be my road bike, maybe use it for Alpine club rallys or something like that. Mainly these odd projects are for educational purposes, and to have something that Jay Leno dose not have.

 

[Agemax]

You should really confirm the spline interchange with Agemax. If they are tha same all it means is that the late GSXR600 clutch hub is a starting point for a slipper conversion. I can confirm that the GSXR1000 spline is quite different to the early GS's.

What is stopping a lot of us from going ahead are the sanctioning body rules....Given that the ZX7 appears to have been the first sportbike marketed with a slipper clutch - in 1988/89 - no body I know of will yet accept slippers in forgotten era/pre 82 or whatever name it goes under where you are....

i dont know how i can help, but i will if i can!

 

[ashdricky]

Agemax, I believe that at some point in the past you posted that the retaining washer for the gearbox input shaft is the same part number for all models, indicating that the splines are the same for the different motors.

 

[Agemax]

Agemax, I believe that at some point in the past you posted that the retaining washer for the gearbox input shaft is the same part number for all models, indicating that the splines are the same for the different motors.

i remember now, that was the clutch hub washer, yes it fits multiple models but it is not splined, just a round hole.....

 

[GregT]

i remember now, that was the clutch hub washer, yes it fits multiple models but it is not splined, just a round hole.....

Okay, that's the heavy, slightly conical washer. i thought you were referring to the lock washer which is splined.
If someone has a part number for that one it should give a pretty good indication of how many models use that spline.

 

[Agemax]

Okay, that's the heavy, slightly conical washer.

it is actually flat, with grooves in it. but anyway it doesn't matter now...

 

[salty_monk]

If I recall correctly I used an 1150 clutch hub nut on my 78 1000E & that was the same as my 83 750E...

 

[ashdricky]

Dose someone have an old clutch from a 1000 that they would be willing to donate or let go for a reasonable price? And are the clutch specs the same for the 1000-1150?

 

[Agemax]

i replaced the clutch plates on a Aprillia RSV Mille yesterday. the slipper clutch design on that bike is so simple and would be an easy mod to do on any GS with a bit of machining.
as long as it has the "pushrod through the shaft" set up, rather than the actuator in the clutch cover.

i am toying with making one for my GS1000, as i have the hydraulic clutch conversion so there is no actuator in the cover itself.

 

[ashdricky]

Is there any chance that the drive splines are similar to the GS?

 

[Agemax]

Is there any chance that the drive splines are similar to the GS?

you use the complete stock clutch, you will need to machine the stock GS clutch cover to fit the Aprilia end cover.
it works by vacuum. a big diaphragm is bolted to the centre of the clutch pressure plate, on the release pushrod. the end cover is sealed with a tube attached which connects to the vacuum ports on the inlets.
when you throttle off the vacuum in the inlet tracts pull on the diaphragm and disengage the clutch just enough to allow it to slip slightly.

sounds too simple but it really works

 

[ashdricky]

I am back stateside and have made more progress on this clutch, here are some photos I took today.

I must now machine the backside of the slipper cam as well as the inside of the hub to get the retaining nut to thread down all the way, then I can machine the back of the basket to have the correct spacing from the primary drive gear.

 

[ashdricky]

you use the complete stock clutch, you will need to machine the stock GS clutch cover to fit the Aprilia end cover.
it works by vacuum. a big diaphragm is bolted to the centre of the clutch pressure plate, on the release pushrod. the end cover is sealed with a tube attached which connects to the vacuum ports on the inlets.
when you throttle off the vacuum in the inlet tracts pull on the diaphragm and disengage the clutch just enough to allow it to slip slightly.

sounds too simple but it really works

I was thinking about what you said in this quote regarding a vacuum operated clutch, did you actually test fit this on your splines? as for my project I had to machine the BTL Cam shorter to get everything to fit correctly. also I was wondering about the ease of tuning GSX-R lift pins to adjust slip percentages vs tuning the amount of slip from the vacuum operated mechanism.

 

[Agemax]

i dont need to test fit anything, as it will work with the stock GS clutch assembly