You will need to start over from scratch on the timing part on the distributor.....make sure the firing order is correct and once you verify that it is correct, I would start out 15 degrees BTDC on the number 1 cylinder compression stroke, look at the rotor button and start from there for your firing order and then try to run it, then once it runs (it will run like crap for a few seconds) try to rev the motor to 3000 rpms and turn the distributor back and forth to wherever it needs to go to get the 32 degrees total timing then let it idle and shut it off. Double check your carbs....make sure they are truly synced out and I mean perfect and that can make a huge difference on how it idles and so forth, also check you intake gaskets, they can make the engine run like crap out of nowhere when the nuts comes a little loose and lets air in that way without noticing. I have worked several buggies like this and it has been the best route I can find to get to the bottom of these issues on the running/idle problems. This will also help to see if your main problem is in your ignition or your carbs at this point. I have ran my MSD for a little over 5 years with zero issues besides the rusting part in the distributor and still using the same one today, I change the cap and rotor button once a year regardless if it is good or not and I keep the old ones for a spare after I check them to see if it is still good to use, if I see a hairline crack or some corrosion on the button and/or cap, I throw them away and buy a new set.
This is the timing light I use and it is perfect.....
http://www.jegs.com/i/Equus/390/3568/10002/-1I just set the timing on the readout at 32 and use the tach on it to rev it to 3000 rpm and see if the TDC is right on the line where the case comes together.