www.zxrworld.co.uk

I have a zxr400l racebike with a zx636shock with a k-tech spring on it and its rock hard, I have it backed off on everything spring is wound out as far as it will go, I can barely get it to move even if I jump up and down on the pegs, what spring rate should I be using on a very light ZXR400 with 12 stone rider.............cheers
p.s I see some people use H2 bottom link on an L model , does this help and do you use the dog bones off an H2 or just the Knunckle/link.

Dog bones should be the same it's just the rocker that is different. Do you know what weight spring is on the shock? I've got a 450 lb spring on the rear and I'm 210lbs without gear or 15 stone.

Hi spring is a K-Tech 55/58-195-85 I dont know what that means but all I know is its rock hard, its a zx636 C1h shock

looking at the Ktec site it appears that the spring rate: 85 N/mm or (486 lbs/in). Based on that fact that I'm much heavier than you I'd say you need a 75 N/mm (429 lbs/in) spring or lighter if your going to get any significant movement for your weight..

Thanks, I looked at K-tech sit but couldnt find a 75nm spring, I have emailed them.
I can get hold of a H bottom link are H1 and H2 the same......
Cheers

Other springs will work as well, ohlins, hyperco, etc... You just need the correct length and diameter and of course spring rate. Another buddy who was about 185 lbs ran a 400 lb spring.

I drew a blank at K-tech, not very helpfull to say the least.phoned ohlins petty much the same response, does anyone have a soft zx636 c1h spring I can buy or even try, and still looking for an H2 bottom link, cheers for all your help so far.

Any suspension guys at the track, local shops that service suspension? They should be able to help you out, doesn't need to be a new spring. I'm sure I can find something here pretty easily, my local independent shop has an assortment of springs since they service both road, dirt track and motocross. There are a couple springs on ebay UK, one listing is from Brook suspension, I'll bet they can assist you.

We fitted a 636 shock to one of our race bikes, and it was rock hard. We sent it to maxton and they resprung it perfectly for £70. Just tell them what bike and what you weigh.