The issue with the gear on this model is as follows.
First off the main door rams are just too thin and weak. I replaced mine with a pair of Jet 1a big boys which work great.
Then the actual gear itself was a pain to get retracted, even though on the ground they worked fine. I sort of cured this by doubling up on the large air bottles for the gear only ( Increase volume of air ) and ran 130 PSI This worked better but still had the odd issue in the air.
What it turns out to be is the speed at which you are flying when you cycle the gear.
I found it on the big Skygate hawk. If you left it too long after take off and the speed built up then no matter what pressure you had the mains would just not go away. Even flying inverted ( Which normally gets any troublesome gear away ) did not help. I think the slightly outward facing doors attached to the main gear cause so much drag that as the speed builds up the restriction is too much. So now what I do is take off, as soon as I am off I throttle back a bit, slow down and then cycle the gear. Hey presto 110 PSi and it works every time.
Hope this helps?
Regards Al