Just in case there is any doubt, the plan is that the bike is a keeper. I enjoy working to improve my bikes and value function over form. I'm also too much of a cheapskate to follow fashion for the sake of it. If making the original forks work sufficiently well is significantly cheaper than replacing them, then that is the path I will take, providing I can make do with the GS wheel. It does however seem a shame not to try to make use of a perfectly good Excel wheel which is next to worthless here on Cyprus because there are so few GasGas bikes.
While I wouldn't claim to be a suspension expert, I am able to set up the suspension on a bike, within the limits of oil height and damping adjusters for forks, preload and damping on the rear. Stripping down a set of forks to replace seals and bushes is no problem at all and I have no doubt I could dismantle the shim stacks in a set of forks and replicate a known good setting. Beyond that, it is time to call in the experts.
I read a thread about the GS forks on ADVrider yesterday which suggested that the compression leg only really affects compression damping towards the end of the stroke since the damper rod is tapered - sort of an anti bottoming out feature - and that the rebound leg actually provides the main damping in both directions. It also described how damper rod forks provide progressive damping - not by the amount of compression but by compression speed - the faster the compression the greater the resistance. The description continued that what is required is divergent damping - plenty of damping of slow speed compression to resist fork dive but less resistance to high speed compression to allow the wheel to respond over bumps. This is provided by modern forks, and to an extent by fork valve emulators, and allows the front wheel to float over hard bumps while maintaining enough damping to control fork dive under braking.
The description seems to match what I am experiencing, The compression damping feels about right under braking but whenever I hit a bump the impact is sent straight through to my wrists, one of which is recovering from scaphoid surgery in November. Based on the description above, I could fit softer springs and attempt to reduce the damping further but to get the forks to work as I want I am going to have to consider either cartridges or cartridge emulators.
Gold-valves are the cheapest option but only fit to one leg, don't adjust rebound and must be removed from the fork to adjust compression. I also came across
these which appear to get round all of those issues while still being half the price of the cheapest cartridge inserts. Conveniently I have friends in NZ so could probably avoid the VAT on import.