My suspension is very stiff, I would like to know why and how to make it better for my size. My bike is a 24" Muddy-Fox Impact hard tail. I went to a trail with friends and they were OK but I was not, please help! I have tried putting oil on the outside even trying to breakdown the suspension by letting my big friend ride it but did not work.
Second site lists this at £160 so its firmly in low-spec price range. Most likely the front fork is based on elastomer and/or a coil spring.
Some questions that discuss the internals of a fork:
and this question states typical sag values which you should measure on your bike.
If you get on the bike and the suspension doesn't sag by 10-25% then you're simply too small and light for the suspension, and softening it could require removing some elastomer or replacing the springs with softer ones.
A more expensive option is to replace the fork with a better one, but this will cost significantly more than the rest of the bike.
As a pseudo-fix you could try adding weight to the front of your bike, with a handlebar bag, front drink bottle cage, or even just getting off the saddle and leaning forward more.
I tried quite a few things with my hard-tailed bike. I put on a seat post with suspension. I got a big cushy seat with springs. I got soft cushy handle-bar grips. They all helped but nothing really did as much as getting another bike with full frame suspension. How much do you like this bike? Is it heirloom? Moderate to unpleasant vibration is kind of the nature of the beast. However, if you are not sentimentally attached to this bike and you want a more comfortable ride I would recommend a full suspension bike.