I've been tinkering with this machine for the last couple of months, fitted a new bobbin tension spring and using the two excellent videos (below) by Uwe Grosse I have been through all the adjustments, re-timed the machine and it seems to be sewing very nicely.
One thing that still baffles me is that the bobbin thread is not in the "correct" location. The thread exits the top side of the spring as opposed to in-between the two prongs at the end and it seems to limit the precision at which you can adjust tension. I've had feedback from others that their machine behaves in the same way, so perhaps this is actually how it's meant to be? Is there any way to get a definitive answer to this?
I'm beginning to think that I prefer the design of the Pfaff 545 I used to own which has a bobbin case that is easily removed without a screwdriver. Much easier to adjust bobbin tension.
Whilst following Uwe's video and adjusting Fwd/Rev stitch balance I noticed a couple of other interesting issues.
I got the point (10:30) in the video where you loosen the screw and adjust the block to balance the stitches, the problem is that on my machine that connection is pinned to the shaft and cannot be moved.
I managed to get the stitches balanced using the under body limiter to limit Fwd and the reverse lever limiter to limit Rev.
The only problem with this approach is that the reverse lever was travelling so far upwards it was hitting the machine casting. The lever is attached to the shaft with two grub screws, one of which locates in a keyway on the shaft. The only way to rectify this was to adjust the lever, which means the grub screw no longer locates in the keyway.
I don't see any way to fix this issue, am I missing something here? It sews well but it bothers me that the lever is not located correctly on the shaft.
When I set the hook timing I did have to adjust the gear mesh of the hook assembly one "tooth" over, could this have put the reverse lever shaft out of phase somehow?
Any help would be appreciated, thanks!
Jeremy