i converted my rear disc brake suzuki s40 to a dual disc brake, two piston calipers on each wheel on my trike conversion. installed a proportioning valve, bled the system 3 times, spilled some fluid on the wheels and cleaned it off with brake cleaner. the problem is the rear brakes are only strong enough to hold bike in place at a red light or stop sign. will stop from an idling speed w/some effort. any ideas would be appreciated.