Valve adjustment on the Breva 750 is straightforward. The main problem is lifting the rocker covers far enough out of the way so you can do the adjustments. They have oil lines attached to the back which restrict movement. These are held on by clamps which, in my case, weren't very tight so the lines came off. I simply pushed the lines back on but later replaced the factory-fitted clamps with proper radiator-type clamps.

The gaskets are very brittle so get a couple of new ones before you start. To date I've only had to replace one. I used some gasket gunk to keep the gasket attached to the rocker cover when it is lifted off, and smear some grease on it when the cover is replaced.

Here's a link to a pdf file - about 1 meg - with pics and description of how to do the adjustment.

Pexi's Breva 750 Valve Adjustment