Uh Oh Low Compression

Ok The results are in.
I ended up going to 2.00 shims on the 2 and 3 intakes. I think there may be a valve job in my future but for now I have the proper clearances.

I did a compression check while the carbs were off and got a consistent 135-140 across all four. Hurrah! I have not rode it yet but it starts easier and idles much smoother. I also took the opportunity to clean the carbs and replace the intake manifold boots and one of the airbox boots.

So far so good. However I noticed I have pressure from the right side crankcase breather. I checked the reeds (although not closely) and did not see any apparent cracking.
What would cause this?

Congrats! 135-140 is pretty dam good. I have no idea about what the standard / service limit compression is for your bike. But I would assume these are good numbers. Balance the carbs and it will run even smoother. Certainly doesn't sound like new rings and valve jobs are required just yet.

Good job man, Your compression is as awesome as mine now!! I can't even fit my smallest feeler gauge in to check the clearance on the Exhaust valve for cylinder 4. Good god.. valve adjusting would do wonders for my bike. Glad yours is running good.