Ive not been on here for a while
Im back now ad I've recently picked up a 89 nc30 and want to change the rear shock .

My question is do any other rear shocks from other bikes fit ?

Depends on budget.

A lot of things can be made to fit depending on your tools and ability.

The S1000RR shock seems a popular option with a spring change lately.

It also depends on your intended usage and ability level with the bike.

For example, replacing a tired old 89 shock with something newer will feel instantly better.

But depending on if the shock is a good match for the bike and rider it might not be as cheap as it seems (revlaving etc can cost a lot)

However, a skilled trackday rider will soon notice that it isnt performing quite right due to it being a mis-matched shock, but for an average rider it will feel great as they arnt likely to push it to the limit.

If you have the time and money I suggest saving up for a proper shock built to your bike and weight, i.e. a nitron.

You'll be able to set it up very precisce depending on the riding conditions.

Thanks for your reply .
I think it would be best for a nitron shock then :-)