my rock shox pike have about 20mm of travel, can anyone give me some tips on servicing as i want to do it myself

Depends on your mechanical knowledge, there are videos on YouTube that take you through step by step. Remember to factor in the cost of the damping fluid, syringes, grease and seals (£30 for the seal kit alone).

Sounds like your fork needs a thorough service though, if you're at all unsure it's worth sending it to TF Tuned who'll charge £79 to do a top class job.

They are very simple inside – sounds like the oil from the damper has gone into the fork leg and given you hydraulic lock so presumably a seal / o ring has failed.

There are exploded diagrammes / instructions on on the net as well

thanks for the advice going to have a look on you tube.will have a look at tf tuned £79 sonds ok to me

Just factor in the postage on top of the £79, £20 pounds picked up and returned using their courier (which I'd recommend). That said I had brilliant and quick service from them (3 days door to door). If the damper fluid is in the bottom of the left leg (which as TJ says sounds likely) a service may not permenantly cure it, there are manufacturing issues with Rockshox forks in this area. Good news though is TFT have their own parts they normally fit if you have a PUSH service but they will fit the appropriate parts as a repair during a normal service as well.

Service instructions here if you want to do it yourself, you'll need the motion control damper kit.

It is also a warrenty job if they are new enough to be still covered, however you will be without your fork longer