Recently had purchased a 600 grizzly that had been sitting for a couple of years , rebuilt the carb and the machine ran great other than being hard to start sometimes.
NOW, it will start normally , let it idle on choke for a minute, take it off choke , idles fine.

But the moment I hit the throttle it falls right on its face and will backfire a couple of times before it dies . It appears to be something wrong with the ignition/ timing but I already tested it with a timing light and it checked out good. Replaced the ignition coil, and tested the resistance of everything I could test. The one problem I found was that the source coil was about 10 ohms over the limit, but I don’t think it could be the problem seeing that the repair manual gives it such a big window of 60 ohms (270 ohms- 330 ohms).

Checked out the boot for the carb to the motor and could not find any cracks or holes.

I am wondering If a bad CDI box could be doing this because it would suck paying $200.00 for a new one and see that it changed nothing. Is there any possible way to test a CDI box other than by process of elimination?

I am stuck and have nothing else to test without throwing more money at it. Any help would be GREATLY appreciated.
Thank you for taking the time to read about my troubles.