I have a ,recently reparied, xj6 divvy f. After the recent repair my back brake seems very 'soft' to push down but more alarmingly it locks up very easily? Could someone give me an idea what could be the caused as I now nothing about bike repairs?

Is this a hydraulic or mechanical brake system?

If it's hydraulic, try changing the fluid and thoroughly bleeding it to get rid of any air.

Also, what condition are the pads in?

You may want to clean out the caliper... or have it done by someone who will teach you (if you're interested in such things).

Lastly (or possibly firstly, if this is a post-crash repair), have the alignment checked and make sure everything is securely bolted where it should be.

Sounds like air in the system and piston lock.

Overhaul the caliper and bleed the brake line.

thanks guys, i'm going to put it in to yamaha

on some calipers under the bleed nipple there is a ball bearing

if the bearing fell out an someone thought they found it but it was actually a different sized bearing this could be it or it may not be there at all

just a thought

Well that shows how much i know about bikes:

Yamaha took it for a quick spin and diagnosed .......... brakes are fine but I had a worn tyre

My uneducated eye looked at tyres and saw loads a tread on outer sides and didn't really noticed the centre

I find that hard to believe twinky" be cautious , till your shure its ok,,, canna see the tyre making wheel lock up, or spongie feel to pedal,,

Scary thoughts just ran through my head,how the hell did you pass your driver test if you cant tell the difference between a worn tire and a good one.

Or the difference between worn brake parts and tire grip? Do you even use the front brake?

I am not trying to insult you but you need some more rider training to learn how to brake if it truley was just a worn tire.Or this wont be your last spill due to poor braking skills.