Pumping up a stock 60-or-so horsepower motorcycle to 80-, 90, or even 100-plus horsepower with torque to match, with those basic Stage 1 or Stage 2 modify kits and a cam swap, opens up a whole new world of motorcycling. But all that new found power won't mean much if it doesn't get where it belongs, to the rear wheel. A high-performance engine needs a high-performance clutch, and the average standard motorcycle is equipped with a basic clutch, also the average motorcycle owner in Thailand seems to be a bit heavier and ridden two-up, would be well served with a clutch upgrade, too. Regardless of the engine's state of tune.
So what's the smart move, the most bang for money? Besides making sure you already have a clutch that is properly adjusted with a little freeplay at the lever, do you replace that original equipment clutch entirely, the hub, basket, plates, the works? There are some great aftermarket race/performance clutch replacement kits available for most modern (and some older models) motorcycles.. All of these aftermarket clutch replacement kits probably get the job done, banishing worries of clutch slip or fade in even the biggest performance motorcycle. This kind of performance comes at a price, though, anywhere from 20,000 THB to 50,000 THB or even more. It's a serious commitment, but in some cases one that's absolutely necessary.
Most street-performance riders, however, can shave that investment considerably and still get the needed clutch upgrade, easily 80 to 85% of the time, all that's required is a stronger diaphragm spring and a switch to better friction plates and steels. Assuming, of course, that the original equipment clutch is still in great shape, which they usually are. Those replacement diaphragm springs, significantly strong than the original equipment ones, coupled with upgraded frictions and steels are in most cases more than enough to harness the output of a street-ridden modified machine.
The feel of the clutch pull at the lever won't change much either, something that can get problematic with a max-performance racing clutch replacement kit, especially in heavy traffic. And best of all, the cost for all this, which basically becomes a routine maintenance job, won't cost you a small fortune.
Those heavy-duty diaphragm springs can be had for anywhere from 1000 to 2000 THB. And they are typically complete kits, with a new spring, and friction plate, and with steels made from superior grades of metal and machined to tolerances much closer than original equipment run.