I'd really try to rebuild the original Brake Cylinder. I have an old M.G., and after buying 3 that leaked, I just honed the old one, and let the seal swell up in some Brake fluid for 5 minutes (Brake fluid makes some rubber swell). It was a real p.i.a. to get in, but it hasn't leaked in 23 years.
A forum community dedicated to Kawasaki Motorcycle owners and enthusiasts. Come join the discussion about performance, modifications, troubleshooting, maintenance, off-road, touring, street bikes, and more!