Another rebore job produced the D5, which was similar to the D3. D7 benefited from better frame, forks and guards. Engine runs okay if used mildly, but small-end, rings and lubrication problems turned up when thrashed or tuned. D10 sorted most of the obvious problems, had relatively modern chassis, much improved suspension and brakes. Tuned motors mean plenty of caution needed but the D10 has a certain amount of charm.
