Recy G sent me the link to the old thread about this mod:
I knew nothing about it as I was away at the time but I thought I'd give it a go, so here it is.
You will need:
1x flat head screwdriver
about 50cm of thin locking-wire
So here is the lever which moves the flap:
And here is the flap inside the left pipe:
Firstly you will need to use the screwdriver to pop the lever out of the hole in the actuator arm so it looks like this:
As was pointed out by siu00adg (post #73) if you leave it like that the flap could quite easily close itself. More than likely the flap would turn around completely and end up about 170 degrees from the closed position (i.e. the flap nearly closed but facing the opposite way) and stay there.
Not only this but the lever arm sits just where you would like the actuator arm to sit and would still be moving as normal so would push the actuator arm out of position.
I decided I would use some .457mm locking wire to tackle the issue (I only had 2 sizes in the locker and the other was too thick):
I tried a couple of ways of routing the wire to hold the actuator arm in place but this is how it ended up:
I started by wrapping the wire through the hole in the arm a couple of times. I then put in a few twists to keep the wire secure. Then I looped both ends around the mount from the front to the back and then tied them off together against the first section of wire.
You may find a better way to do this but the idea is there.
The flap position is not perfectly flat but I would have thought it's free flowing enough anyway:
I have not had a proper drive to try it out yet, only drove back from the workshop to my room, 1/2 mile at 20mph limit. I will be going out later to get some food so I will post results then.