OK then, call me a newb if you will but ive never performed a valve check or compression test you guys have any pointers? does it require me to take the engine out... again? I'd really like to get it on the more practical. Believe it or not i am actually studying mechanics! I wish to be wise on all aspects of motorbikes...

Luke there are going to be loads of opinions on this but here is my take;

Firstly you need a manual for your bike and a basic understanding of what is involved in a valve clearance check.
A copy of the factory manual can be downloaded on line but I would highly recommend the Clymer manual for the FZR600.
It is so near to the 400 (of which there is no hard copy manual in english) that it makes little difference; but mainly it is excellent for generally talking you thru a procedure;where the factory manual expects the reader to know the basics.
Here is a cheap copy;http://www.ebay.co.uk/itm/Yamaha-FZR600 ... _71wt_1012

You can do the valves in the bike but it is awkward.
On the bench is much, much easier which is why when building them and the engine is out it is foolhardy not to check.
I know for a fact Boris does it this way also.

I use the compression tester to see if the valves are at least closing fully.
It is by no means a guaranteed method (too many other things influence the reading) but it can save major teardowns.
At this point you need to read Mang's thread "Won't start".

Here is a link to a shim job on a 400;
http://www.gtamotorcycle.com/archives/s ... -on-FZR400

Checking them is much less involved than actually having to change the shims.

online works manuals;

http://www.carlsalter.com/download.asp?p=1299

http://www.fzrarchives.com/ipb/index.ph ... opic=36294 (download all parts)

Ok well a pretty hands on job at hand then! I will have a gander at that link and find that thread Always was a little bugger to start, dont get me wrong it runs... but isnt easy to start, lets say it gets the blood flowing and pressure up hopefully soon i shall get to the bottom of it once i've cleaned the shed up! thanks alot for the advice, been a great help, both you guys