Whenever we GSX-nuts have nightmares about engine breakage, we are usually thinking of holed pistons, dropped valves, snapped camchains, and other such tragic events. But how many of us think of broken clutches?
Well, we should. Because the fact is that once you've started hotting up your GSX donk, and you've been beavering away and slotting in all sorts of goodies (oversize piston kit, hotter cams, better exhaust, bigger carbies, etc.), you just kind of forget about the clutch. Until it starts slipping. So then you stick in some heavier springs and forget about it, right?
Wrong. The original Suzuki clutch basket backing-plate is made up of a thin piece of steel (ie. only 2.5mm thick might as well use alfoil) that is going to bend, buckle, and in due course BREAK. Take a look at the old backing-plate I pulled out of my Katana's clutch...
... and you'll see that the wretched old thing was starting to bend adjacent to each of the three rivets. So, what happens when one of these things breaks? Well, the backing-plate pieces will gouge the gearbox casing wall at around 43 meters per second, or a bit under 100mph (this is calculated on the breakage occurring at a conservative 6500rpm). Let's just say that a lot of damage is going to happen in a very short time. But that is only the beginning of your worries, for in the next split second the hardened metal springs (which are there to absorb the shock from the primary drive) will also be released into the metal maelstrom and graunch their way into the oil pump gears and then the primary drive gear, sending showers of unforgiving shrapnel into the proceedings and naturally RUINING THE ENGINE beyond feasible repair. You have been warned!
The solution is a new clutch basket backing-plate, complete with heavy-duty springs and thicker rivets for good measure. It's all fairly easy to install you just need to pay attention to how things have been assembled as you dismantle the old basket. And dismantling is easy to do; just take the heads off the old rivets with an angle-grinder.
That done, I drilled slightly larger rivet holes in the clutch basket (a 7/16" drill gave the perfect 11.1mm required) to accommodate the HD rivets. Then it was just a matter of clamping the backing plate onto the clutch basket with all the springs in place, and getting the rivets TIG-welded to the backing-plate. Whacked it all together with a new clutch hub lock-washer, clutch cover gasket, and I am happy to report that the awful clutch rattle has disappeared. Noice!
And where do you get one of these kits? Falicon and APE seem to be the main producers. I ended up getting my Falicon kit through S&K Racing as their price was quite reasonable, esp. compared to the prices being asked in some eBay stores.
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Naturally, it got me thinking: the GS1000's clutch was a bit rattly. But, as it doesn't have anywhere near the amount of grunt of the Katana, it wouldn't need a new backing-plate, I thought. Just pull it apart, take up any slack in the springs with washers, press it all back together and TIG-weld the rivets. What could go wrong?
So I did exactly that. Upon pulling it all out, the 6 springs in the back of the hub were indeed rattling around like there was no tomorrow. So I got out the trusty angle grinder, carefully took the heads off the rivets, and knocked them out with a big hammer (my 2½ lb ball-pene knock-o-meter dubbed "Big Al") and a punch. Then I was able to pack the springs with some