Jake brake adjustment

[Wiseman]

I hope this will help you to understand why this small clearance needs to be adjusted by rotation of the rocker shaft .
When the rocker is held by the detent you have to be sure the roller doesn't ride on the camshaft lobe and you have enough clearance. And this have nothing to do with the 7mm which is adjusted with rocker out of detent position.
Now about the +/- . Even from the factory not all valves have absolutely identical height due to factory tolerances when valve seats are grind . There's small differences from valve to valve and from cylinder to cylinder. With time valves tend to sink into the valve seats and that's why we need to make valve adjustments because they are getting tight. Some more some less . Here's where turning the rocker shaft comes to play and you make all 3 rockers when in detent position to have enough clearance for the rollers not to ride on the camshaft lobes. The 7mm have nothing to do with . First you do the 7 on all 3 , then check clearance and rotate if necessary. 7 will still 7 .
If impossible to make all 3 within speck your engine head is shot because the valve/s have sunken already enough irregularly from cylinder to cylinder into the valve seat/s and ready to brake do to seating on its very edge .

If Rawze wake up in a good mood and responds with manufacturer cover up don't be surprised.
Either way keep the fire extinguisher as close as possible.
He wrote about this . It's somewhere in the treasure chest.