There were Kohnis on my 2002 Plus 8 when I bought it. To adjust they would need removal and bench to adjust, but a problem was that internals could break so adjustment from the setting at the time was not possible. Not a huge range available anyway. One of mine (rear) failed so I replaced front and back with AVO's from Tim Ayers. There then followed a period of adjust and test until I was happy. Definitely an improvement with everything checked ( rear leaves lubed, front springs looking correct, tyres/pressures set etc)The next job was to fit Rog's bump stops but didn't get round to that. We have speed bump breeding areas here so they were a consideration!
I forget the settings I ended up with but rears tended to slightly softer side of mid point. Fronts unsure of clicks used. Test on hardest then softest to see the extremes then mid point and small tweeks from there. Regular route to reduce variables.
The AVO's were a definite improvement.
