Rated: Sigma slipper clutch for Kawasaki ER-6


Tested by Adam Child, MCN Senior Road Tester

Time tested three months/ two racing weekends at Oliver’s Mount

What’s good? My Lightweight TT bike is producing just short of 90bhp and the standard ER-6 clutch can’t take the strain, not to mention that but there’s no slip action on the stock clutch meaning that there’s the potential for the back wheel to lock during hard downshifts. Sigma have resolved this problem with a six-spring clutch rather than the standard five which means you don’t have to preload the springs. You can use the standard friction plates, but with one added spring. I’ve used it at the last two meetings at Oliver’s Mount on my Lightweight race bike and it’s cut my lap time by around a second; really impressive. Now I can slam down the gears and let the Sigma clutch control the back torque to the rear wheel. It’s transformed the bike on the brakes and  it allows me to free up brain power to concentrate on other aspects of my racing.

What’s not? Not a huge amount. I’ve been brutal with the clutch and had no problems, even after two hard race weekends. 

Quality rating: 3/5

Value rating: 3/5