I am having a stalling problem with my Rekluse Z start clutch. It seems to occur when the engine is under heavy load at lower rpm. The clutch does not disengage properly and the engine stalls. I have checked the installation clearances and tried altering the spring tension in the perch adjuster. The spring tension change does work as expected. Increasing the spring tension increases the rpm at which the clutch engages. The problem is that in tight technical sections at low rpm the clutch does not disengage properly and the engine stalls. Recently I had to walk the bike out of a real nadgery bit and the clutch engaged and disengaged correctly with no stalling so the problem appears to be load related. Playing about on a flat surface where the engine is only lightly loaded does not produce stalling. Has anyone else had this problem? I am using semi synthetic oil and the light spring as described in the instructions.