I see alot of members have problems with drive sticking on Greenfields, I just went to change drive belt and noticed one of the bearings had been spinning on main shaft as it appears grubscrews were loose. I got a new shaft and changed over all clutch drive parts then reassembled. This is where my problems started with drive sticking in forward. I made sure that forward and reverse clutches were on correct sides and all shims in original location,before reassembly so I thought I hadn't changed anything. After some head scratching and staring at clutch I found the problem. I noticed the way the belt drive pulls on main pulleys they are not parallel to each other being around 5mm wider at front than rear . I took drive apart again and found clutch plates although still in good condition were worn uneven measuring 3mm at thickest point and 2.4mm at most worn side. Logic told me to clock forward and reverse pulleys so high points were opposed to even things up, how wrong I was and this made things worse. So I decided to put both worn sides in line on square shaft. This solved my problem and it is now running perfectly again . Looking at it now I guess this is the way they have worn in and when you put pedal in neutral the clutch finds this position by itself. Sorry for long post but hope this may help someone. I guess my tip would be to mark both pulleys before removing so they can be reassembled in the same location to each other