If you want to tune it on the cheap, piston seal from maccari in the US, POK! on here for the spring (if original spring is good then re-use), send the lot to someone like UK Neil for spring guides / top hat & to button the piston / size the piston seal.
www.savedeathrowdogs.co.uk Very urgently need homes for: Male staff cross, approx 1 year old, will be neutered, very loving but not great with other dogs. Stuck in pound. 2) 2 year old male choc lab. 3) 2 year old cockerpoo. 4) 20 border collies .