I have been through the forums and have not really found any similar problems posted so though I'll start a new thread.
I am currently working late shifts (retail management between 6pm and 3am) riding from my place to work is lovely and steady no real problems but upon my journey home I have odd issues.(its only at home time during the day there are no problems)
I leave my bike to warm up as its normally cold around this time in the morning after its warm (usually 5 mins or a little longer) I'll ride off but when I come to junctions or roundabouts I'm unable to gear down in a normal force its almost as if its stuck. When i've managed to gear down my bike also pulls down (as if I'm braking hard on the front brake) but with a little revs its okay.
I'm not 100% sure if I'm at fault for not letting it warm up long enough or if this is a known issue, I've had 2 do a lot of work on this bike as the previous owner didn't look after it so I'm not affraid to get my hands dirty

any suggestions as to what it could be would be great.
many thanks for looking and any suggestions you've given.