GpZ550 Turbo Clutch Upgrade

ZL600 clutch cover is needed to clear the 636 clutch . See last pic
The 2 dowel pin locations on the cover need to be moved to match the 550 engine case. Counter bore the 2 correct bolt holes.
The 6 spring ZL clutch would also be an upgrade for the 550, and together with the ZL clutch cover, it's basically a bolt on option.
Since the ZL600 uses 63/28 primary gears and the 550 uses 65/26, you either move the 550 clutch gear to the ZL clutch OR replace the front smaller gear with the 28 tooth from a ZL or ZX600.

ZL600 clutch cover fits nicely and with the oem ZX550 cable routed on the right side, clutch action is perfect.
The three 636 clutch springs make for a nice light pull at the lever. With springs so light the "assist" feature better work or it's gonna slip like crazy.

Waiting on replacement rubber clutch dampers from Turbosteve84@verizon.net
He makes them for both the 550 and 750 and are $45 plus shipping.
Rivets get drilled/punched out so the gear can be removed, then the holes are threaded M6-1.25 and special ultra low head screws are used for reassembly.

The ZL clutch cover got cleaned and painted while I wait.
AFTER oven curing the paint the unused ZL dowel pin holes were filled with epoxy. The two bolt holes that match up with the 550 engine case were counter bored for the dowel pins.

Ready for road testing.

OEM 550 clutch pull rod and bearing work perfectly with the 636 clutch.
Release lever angle is correct and the stock zx550 clutch cable provides a bit of adjustment so it can be easily removed.

Should provide all the grab needed. Stock 636 dyno runs show around 106 hp but that clutch works with modified bikes as well.
I estimate my power at around 125 hp which is comparable to a stock naturally aspirated gsxr750. I will eventually get it on a dyno but in the mean time I can compare to my coworker's 2012 GSXR750. The only other 600 I've ridden was a 05' CBR600RR. This turbo build would smoke it

My 1250 bandit put out 123hp at the rear wheel and this bike is easily as fast but without the massive torque.

First Test ride is complete.
Clutch is a success and with the new rubber clutch dampers the transmission is smoother than I could have imagined.
I highly recommend replacing the old shrunk and/or possibly cracked dampers in our old bikes. The difference is night and day.

I also like the new ratio from using the ZL primary gears.
Definitely tames it down a bit and with the 17/39 sprockets, 55mph in 6th gear is 4000 rpm.'

I pushed it as hard as possible on the road and as adjusted, the waste gate will allow 13 lbs boost. The throttle must be wide open long enough to hit 13lbs which rarely happens. I think I detected a bit of clutch slip at 13 lbs boost but for now I'm not worried about it. It's much better than the 550 clutch.

Thanks for posting this project.
That is a mighty tidy turbo install.

Thanks for sharing. Great build.

So I installed new friction plates ( in the 636 clutch and so far haven't made it slip.

BUT I'm not done.

I've decided to add 1 more friction plate for a total of 9, and put it over the top.
The 636 outer steel plate is special and only comes in 2.3 mm but the 7 other steels can be 2.6, 2.3, or 2.0 mm.

I did some checking and found the KLR250 uses 5 of the 2.0 mm steels Same part also fits several other bikes including the 70's era 750 2 stroke tripple.

Anyway I bought a Vesrah aftermarket steel KLR250 kit for $27 (delivered) and 2 more NOS steels off ebay.
Together with the OEM 636 outer steel plate I'll have 8 steels and space for 9 friction plates.

Together with the "assist" feature the clutch should handle all the power and wear very slowly.

Should have all the pieces by this weekend.

Just an update.
I did finally rebuild the clutch pack with seven 2.0 mm steels and the one special 2.3 mm outer steel plate that locks into the pressure plate.
So 8 steels and 9 friction plates.
No problems with assembly at all. Stack height is virtually the same.

This is the final clutch upgrade as there's nothing left to do.

BTW. The friction plates are the same used in most ZX10 years as well as most GSXR 1000/750 and the newer YZF R1.
The ZX10 uses 10 friction plates to handle all that power and the new model also has the "assist" feature with 3 soft springs.