Apparently not. I tried Googling a bit but didn't make out any better than you. I did come across a place to ask Northern Tool questions but it didn't work for me.
I would call Northern Tool and ask them for some direction. Or maybe some small engine repair shops. The stupid manual I downloaded lists "check valve lash" as a once a year maintenance....but doesn't list specs!!!!
If I were going to give it a shot in the dark I would go .004 intake , .008 exahust.
IIRC...That's the older Predator specs, I believe the newer ones are .003" for both.
Wait!!! I know someone that HAS to know!!! Can you speak Chinese?
---------- Post added at 11:48 AM ---------- Previous post was at 11:21 AM ----------
You do have some leeway in valve lash anyway. As long as there is
some clearance at operating temperature....even a very very small one...(while running) ...the engine will work just fine. Factory specs have a little extra for saftey...
I learned that those in the know set the valve lash on Toyota 22re engines a thousand tighter than minimum factory specs. If you think about it: that will make the valve open a hair sooner and give it a hair more lift.
Conversly, the opposite will happen if you are a couple of thousands loose, but the engine will only loose a very small amount off peak performance and still run very well. It may wear a little faster, but if it runs well and the rockers aren't noisy...It's probably fine.

to the forum and please fill out a profile location when you get a chance. This place is more fun when you do.
Oh...forgot to mention what happens if you get too tight or loose...(so you can play with it if you wish) : too tight on the intake and it will cough out of the carb. Too tight on the exhaust and it will pop fire out of the muffler. Too loose on either will make noise. But it's best to find those factory specs. Good luck!