noisy transmission

[shortfuse]

I'm getting some grinding noises from my Fazer, most noticeable at lower revs when gently applying the power. They are accompanied by some light knocking.  Coming down through the gears all sounds normal. Having read the 'Gear and Bearings' paragraph in here http://www.ehow.com/how_6535630_troubles...ssion.html my view is that the problem is probably one of the countershaft bearings.
Does anyone agree with this diagnosis and if so do you know how easy/difficult it would be for a willing novice like me to have a go at fixing it myself?

Thanks