To ride or not to ride??? Well, let's see what would/could happen. If you're just a little too lean, then the motor will get hot, and potentially you'll get detonation (pinging) and we all know that's a bad thing. If you only put a pipe on, but left the airbox lid on, then likely it would run a bit lean at sea level to about 1500 ft elevation. If you're in the 1500 to 3000 ft elevation, your jets may not be that far off.
If you're REALLY lean, then at first, the motor will bog under full throttle at high rpm. You'll quickly find that you won't want to ride like that. If you do, and you ignore the grenade explosions that severe detonation will cause, you better plan on major engine repair.
I would literally play it "by ear" if you MUST ride. Take it easy and listen for knocking/pinging noises. If it happens, STOP RIDING! I would bet that if you just want some mellow break in time, you won't have much of a problem, but remember the risks. Is it worth the expense of possible damage?
If it were my quad, I'd rip the bowl off the carb, pull the main jet, go buy a few larger jets at a local shop and fatten up the jetting until it runs well on top. Raise the needle until it runs well in the middle and turn the airscrew in a turn or so for idle and low rpm. In the end, I'd have (and always end up with) a bunch of extra main jets for high elevation operation. Heck, a handful of jets is a lot cheaper than a hole in your piston...