The rear is easy as you can get the cam cover off (which you have to do to get the right tension)
The front is more tricky as it is not as accessible, but I found that by taking the carbs off too I could get to the bolts from the top. As long as you don't fiddle with them you can just replace them abd they won't need rebalancing or anything.
A methodical and fairly simple job - DON'T overtighten the cam cover pillar bolts. Some idiot I know
