UKH

I have a Planet X Jack flash 29 hardtail with a Rockshox Judy 130mm fork. I’ve been thinking of upgrading the fork to a Pike or equivalent, but wondering if I should increase the travel to 140mm? 
 

I don’t do anything too crazy on it mostly trails and the odd downhill (usually BPW Blues). Any thoughts on which travel would be best? Also any other form recommendations? 
 

(Alternatively do I just get a full sus 😂😂)

Can the frame take a 140mm fork?

Doing so will raise the front end.

Is the current fork lacking, what do you expect a Pike to do better than a Judy? and will that be noticeable by yourself. 

Only you can decide which will be best.

140mm Pikes should go nicely on that.

Most bikes can easily take +/- 10mm travel without noticeable difference, it's something like 0.5° at the head angle an a couple of mm BB height at most.

Id recommend a pike with the rct3 or rc2 damper rather than the basic charger RC which is rubbish. I've just upgraded my damper which was quite pricey Vs buying one already fitted.

Id save the money for a new bike later or lighter wheels. It doesn’t sound like you’re maxing out your current fork on blue trails. Most people have way too much bike for what they ride.